ML19208D495

Reactor Basement Concrete Second Testing Program.

ML19208D495
Person / Time
Site:	Wolf Creek
Issue date:	02/27/1979
From:	Shideler J AFFILIATION NOT ASSIGNED
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Text

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Report to DANIEL INTERNATIONAL CORPORATION Strawn, Kansas

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WOLF CREEK G1;NERATING STATION REACTOR BASEMAT CONCRETE SECOND TESTING PROGRAM by J. J. Shideler Submitted by CONSTRUCTION TECHNOLOGY LABORATORIES A Division of the Portland Cement Association 5420 Old Orchard Road Skokie, Illit.ois 60077 February 27, 1979 1050 217 7 9 09 280 WJ

geg,truction = =o- ~ =~ - - - -= -

technolegg Reboratone, P00R01,Gh,p e Ms om et tw PCRTLAN3 CluENT ASSOCAtlON February 27, 1979 Mr. Glenn L. Koester Vice President - Operations Kansas Gas and Electric Company Wichita, Kansas Re: Wolf Creek Generating 'Jtation Reactor Basemat Concrate Second Testing Program Mr. Koester:

We have completed the testing program outlined in Mr. W. R.

Waugh's letter of January 12, 1979, to you and authorized by your letter of January 19, 1979, to Mr. Hitt.

The attached reports together with this covering letter com-prise our recort.

The Petrograohic Services Recort (Appendix A) gives results of:

1. Microscopic examination of the cylinder remnants to determine:

- general quality of the concrete,

- paste-agg regate bond,

- evidence of deleterious reactions.

2. Compressive strength of 2-in. cubes cut from the bottom remnants of previously tested 6x12-in. cylin-ders, and comparison of cube and cylinder strengths.

3. Air content determinations by the method described in ASTM C-457.

4. Deviation. _ sm planeness of the bottoms of the tested cylinders .

The Chemical Services Reoort (Appendix B) gives results of cement content ceterminations on the designated cylinder remnants, and compressive strengths of ASTM C-109 cubes for four cements designated as CUT-15, -18, -20, and -21.

Principal conclusions are given on the first page of each of these reports.

1050 218

l ccwtsuction tschmdo99 aborotoe*w age February 27, 1979 Of major interest is the relevance of the strength of. 2-in.

cubes cut from tested cylinders in estLaating the strength of the cylinder and the in-place basemat concrete.

The attached bibliography "Effect of size and Shape of Soecimen on the Comoressive Strenoth of Concrete" (Appendix C) gives principal ref erences on this subJ ect, and some of the papers list as many as 128 additional references. Much thought and research has been given to this subject, but I do not find any reference to the relationship between cubes sawed from tested cylinders and the strength of the cylinder. .

I have reviewed the conclusions of several of the authorities on the subj ect in the attached summary " Ratio of Strength of 2-in. Cubes to 6x12-in. Cvlinders" (Appendix D) . The general conclusion is that the strength of cubes should be reduced by a f actor of about 0.80 to equal the strength of 6x12-in. cylin-ders. In all cases, the data are based on molded cubes and cylinders.

The attached memorandum "Possible Causes of Retrogression of Strength of Concrete" (Appendix E) lists and discusses several possible causes of retrogression of strength. None of these apply to the composition of the subject concrete or to its environmental exposure. In my opinion retrogression of strength of the subj ect concrete can be totally discounted.

It is my belief that the erratic reported compressive strengths -

of the 90-day cylinders, both with respect to sequential and companion cylinders, was due to some combination of improper testing procedures. The most probable circumstances. include the large number of cylinders tested in a given day; improper capping of cylinders, possibly due to temperature control of capping compound or contamination by oil from the capping jig or plate, sometimes "f rozen" head of the testing machine, and lack of proper alig,t int of cylinders in the testing machine.

Sincerely,

, , 4 JjG.fhideler , Director Admi6istrative and Technical Services JJS/md CT-0407 Copy to- f W. E. Kunze E. Hognestad 1050 219 L. M. Meyer D. H. Campbell

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APPENDIX A PETROGRAPHIC SERVICES REPORT O

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9 1050 220

Petrograohic Services Report Proj ect No.: CT-0407 Date: February 27, 1979 Re: Daniel International Corporation Remnants of 48 6x12-in. concrete cylinders, previously compres-sion tested at age 90 days, and four samples of cement were delivered December 13, 1978, to the Construction Technology Laboratories from Daniel International Corporation for addi-tional testing and examination relating to a reported problem of low 90-day cylinder streng ths. The concrete represents materials used in a nuclear reactor basemat at the Wolf Creek Generating Station. K.G. & E./ Daniel have certified that concrete cylinder remnants delivered to PCA are representative of concrete in the subject basemat. The present report covers compression tests on 2-in. cubes cut f rom some of the received cylinders, petrographic examinations, and determination of air contents of selected cylinders. This investigation was directed primarily to those cylinders that had reported strengths of less than the specified 5000 psi at age 90 days.

Findincs and Conclusions

_ 1. Compressive strength tests of 2x2-in. cubes cut from previously tested 6x12-in. concrete cylindern indicate an average corrected strength of 6690 psi, with a range of 5340 to 7930 psi. These reported values are 80 percent of actual measured compressive strengths of the cubes. .

2. Measured air contents ranged from 4.0 to 5.9 percent, averaging 4.9 percent. - ,

3. The paste is hard and firmly binds the aggregates.

4. No evidence of inadequate mixing was observed.

5. No evidence of paste- aggregate reactions was observed on freshly broken or lapped surfaces, or in thin sections.

6. These data strongly suggest that the concrete is of

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high quality, the materials being properly propor-tiened, batched, and mixed.

Test Methods After initial photography of all received cylinder remnants, those from which one or more 2-in. cubes could be cut were listed. Each cylinder was examined and the exposed fracture

_1_ 1050 221

surface, from the previous ccepression test, was described. A square was laid along the side of the cylinder and across the bottom, and using a depth gauge-vernier caliper, the unevenness of each remnant cylinder bottom was measured and recorded.

Cylinders from which cubes were to be cut were selected in consultation with W. G. Eales of K. G. & E and W. R. Waugh, consultant (see Mr. Waugh's letter of January 12, 1979 to G. L.

Koester and Mr. Koester's letter of January 19 to W. E. Hitt).

The cylinders selected, in most part, represented those giving low strengths at age 90 days. Thirteen of these had strengths below 5000 psi, and six below 4500 psi.

From each of the 18 cylinders dasignated to supply a 2x2-in.

cube, a longitudinal side piece was cut and the cut surface on the body of the cylinder was used as a " reference surface" for the remaining cuts to produce the cube. An arrow indicating the longitudinal direction of each cylinder and the cylinder number were placed on each cube during its preparation. Each piece cut f rom the cylinder was also labeled with the cylinder number. Af ter the cubes were cut, measurements between center points of opposite top edges and bottom edges were made in order to calculate surface areas. The minimum surface areas were used in the calculation of compressive strengths, af ter correction of surf ace areas for those cubes showing slight damage (missing edges or corners) due to sawing. Cube height was also measured. All of the remnants from which cubes were cut were bottom remnants.

The cubes were checked for obvious cracks, using a stereomicro-scope and alcohol, then placed in water for at least a 48-hour soak for determination of tinit weights. The tops and bottoms of the cubes were lapped te insure smooth surf aces.

Coreression testing of the cubes was accomplished in a Southwark-Emery Testing Machine, Serial Number 57271 of 75,000 pounds capacity. The machine was recalibrated immediately following the tests and found - to be in compliance with ASIM E74, Standard Methods of Verification of Testing Machines (see attached Calibration of Testing Machine) .

After testing , each cube was weighed and placed in an ovan at 1050C for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> in order to calculate absorption for use ,

in chemici.1 tests.

Lapped longitudinal sidepieces from 11 remnant cylinders designated by Mr. Waugh (see again Mr. Waugh's letter of January 12, 1979 to G. L. Koester) were used for determination of air contents (ASTM C-457, Standard Recommended Practice for Mic;oscopical Determination of Air-Void Content and Parameters of the Air-Void System in Hardened Concrete) and petrographic examinations (most of which is. covered in ASTM C-856, Standard Recemnended Practice for Petrographic Examination of Hardened Concrete). Thin sections were prepare? by drilling a one-inch 1050 222

diameter plug from a 5 elected area of each lapped sidepiecer the plug was then sliced and placed on a glass microscope slide with epoxy resin and reduced to a thickness of 25 microns for determination of aggregate and paste mineralogy, and paste microstructure with a transmitted polarized-light micrcscope.

Numerous f reshly ' broken surf aces and the lapped sidepieces were also studied with an ordinary stereomicroscope.

Results and Discussion Accrecates Coarse aggregate is crushed limestone of various types (fos-silif erous, microcrystalline, sandy, pyritic, with minor amounts of dolomite and clay) . Fine aggregate is a natural sand composed of grains of quartz, feldspar (microcline and plag ioclase ) , metaquartzite, and chert. Aggregate dust occurs in trace amounts, indicating properly washed materials.

Aggregate distribution is uniform and no occurrences of segre-gation were observed (Photog raph 1) . Aggregates appear prop-erly shaped and distributed, and of moderate hardness. Coarse-to-fine aggregate ratio is approximately 55/45 to 50/50.

No evidence of paste-aggregate reactions was observed on freshly broken or lapped surf aces, or in thin sections.

Paste The paste contains normal hydration products (primarily calcium silicate hydrate and calcium hydroxide, abbreviated as CE) and is evenly distributed in all samples observed. The paste is hard and firmly binds the aggregates, as indicated by numerous ,

sheared aggregates both on freshly broken surfaces and on those present on the cylinders (as received) .

Thin-section data on the concrete pastes are presented in Table 1. Percentages of unhydrated portland cement clinker particles (UPC's) range from 12 to 26 percent of the paste (see example in Pho.tograph 2), the data presented included a reassessment of thin sections from cylinders received in March 1978. UPC's are comprised of normal clinker phases (alite, belite , aluminate , and ferrite) with the ferrite phase being dominant, as expected because it is relatively slow to hydrate.

Residual alite (impure C 3 S) shows prominent rims, a common f eature in most concretes.

Calcium hydroxide (CH) occurs mostly as small irregular, micro-crystalline masses in the paste and as narrow aggregate fringes.

Blade-form CH is common.

Abundances of UPC's and relative scarcity of CH suggest a moderately low water-cement ratio (w/c) for all the cylinders

_3_ 1050 223

examined by thin section. A w/c of 0.45 to 0.50 appears to be a reasonable interpretation.

The amount of unhydrated cement clinker observed is not detri-mental to the compressive strength of the concrete. As a matter of fact very high strength concrete generally would have consid-erably more unhydrated cement clinker than observedin these samples.

Concentrations of UPC's around coarse aggregates were not observed in significant amounts; thus mixing is judged to be adequate.

Fractured Surfaces on P.eceived Cvlinders and Mold-Bottom Imoressions The type of f racture surf ace on the received cylinder remnants was described (Table ?) before preparation af the respective cubes. As Table 2 indicates, most of the cylinder remnants have a strong tendency to display diagonal f racture surf aces as a result of compression testing. A typical diagonal fracture is illustrated in Photograph 3. The diagonal f racture, a departure from the ideal conical fracture, may suggest a problem with the testing machine or procedure. Most broken surfaces on the cylinders expose cross-fractured aggregates.

Measurements of maximum relief on the bottoms of the received cylinders (Table 3) shows considerable variance. The cylinder botto=s are generally uneven with a central, relatively "high"

' point. Some of the- bottom surf aces were warped. The cause of mold warping is not apparent, but its eff ect was to produce an uneven bottom surface on the concrete cylinder. The effect of the unevenness may have been eliminated by the sulfur capping compound. A plot of 90-day cylinder strengths vs. maximum -

relief shows no observable correlation (see Fig. 1).

Cube Comoression Tests Cube compressive strengths (corrected) range from 5340 to 7960 psi, ave. aging 6690 psi, with a standard deviation of 675 psi (Table 4). These reported values are 80 percent of actual compressive strength of the cubes. A plot of corrected cube strengths and 90-day cylinder strengths as a function of cylinder number shows similar patterns of strength variation (see attached plot) .

Areas used in calculation were corrected if small portions (edges or corners) of the cubes were missing due to damage in sample preparation. After the cubes were sawed, inspection revealed that cubes f rom Cylinders 6558 and 6767 were cracked and these were not compression tested.

1050 224 Air Centert Data from linear traverre (ASTM C-457) indicate a range of air contents f rom 4.0 to 5.9 percent, averaging 4.9 percent, with a standard deviation of 0.58 percent. These, and other air void data, are given in Table 5, which also shows unit weights and absorpticas of cubes for which the cement contents were deter-mined. The range in air contents, although known to have an eff ect on cylinder strengths, is not of a magnitude to cause the strength fluctuations reported by Daniel. There was no correlation between. determined air . content and reported com-pressive strength of cylinders. The volume percent air in voids greater than, or equal to, 114 microns is slightly higher than normal air-entrained concrete, but is judged to have no signifi ance with respect to compressive strength.

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D. H. Campbe , Supervisor Petrographic Services Technical Services Section DEC/md CT-0407 Copy to-J. J. Shideler L. M. Meyer O

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TABLE 1 - MICROSCOPIC EXAMINATIdit " * ~l n

(Thin Sections) j Cylinder Percent Percent No. UPC s* CH** Miscellaneous 6540 12 - 15 10- 14 Fringe and blade CH** common 6546 16 -20 12- 15 Blade CH scarce; largo inter- <

paste CH 6551 22- 26 10- 12 Common, blade CH; trace E**

6558 18-22 10-12 Common, blade CH 6599 22- 26 12- 16 Common, blade CH 6606 22 -26 10-12 Common, blade CH 6659 16-20 10- 12 Common, blade CH 6671 22-26 10 -14 Voids contain traces of E and CH; common, blade CH 6696 22-26 12-16 Common, blade CH 6767 16-20 10 - 12 Common, blade CH and carbonation 6785 18-22 12- 15 Common, blade CH -

• 6444 16-20 12- 15 Common, blade CH

• 6503 16 -20 10 -12 Common, blade CH

• 6784 12 - 15 12- 15 Common, blade CH ,

• 6850 12-15 12-15 Common,. blade CH

• Percentages of the paste estimated by comparison with per-centage diag ram; last f our cylinders re-examined. (Pre-viously examined per our report of 4/19/78.)

• • E ref ers to ettringite CH refers to calcium hydroxide CT-0407 1050 227

T. ELE 2 - FRACTURE SURFACES OBSERVED ON CYLINDER REMNANTS (As Received)

Cylinder No. Type of Fracture Cylinder No. Type of Fracture 6527* D/L/T 6659* D 6533 C 6660 D 6534* D 6671* T/L 6540* L/T 6683* D -

6546 D/L 6689* D 6551* D/T 6690* D 6552 D 6695 T/L 6557 D 6696 T/D 6558* (cube C 6713 L/T not tested) 6563 D 6714* D 6575 D/T 6720 D 6576 D 6725 D 6582 D 6726 D 6587 L/D (?) 6731* L 6588 D/T 6737 T 6594 D 6744 D 6599* L/T 6761* D 6605* D/T 6767* (cube D not tested) 6606 D 6772 D 6611 D 6773 D 6629 D 6779 D/T 6636 D 6785* D/T 6642 L 6790 L 6648* D 6845 D .,

"Cyllnoer from wnich cube was cut.

D = diagonal C = conical T= trans verse L = longitudinal CT-0407 1050 228

4 TABLE 3 - MAXIMUM RELIEF ON CYLINDER ENDS From Highest Point to 90-Day Cylinder Y #

N*

Lowest Maximum Relief S trength , (psi)

(inches) 6527 0.122 4700 6533 0.061 4810 6534 0.050 4660 6540 0.046 4320 6546 0.044 3270.

6551 0.097 4290 6552 0.049 5110 6557 --- No bottom surface 4180 6558 0.042 5380 6563 0.067 4620 6575 0.029 5600 6576 0.036 5090 6582 0.072 5130 6587 0.050 4670 6588 0.048 4970 6594 0.074 5310 6599 0.046 4010 6605 .0.061 4350 4340

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6606 0.071 6611 0.039 5180 6629 0.095 6270 6636 0.135 5620 6642 0.069 5460 6648 0.065 5150 --

6659 0.053 5390 6660 0.035 5530 6671 0.135 4370 -

6683 0.027 4990 6689 0.113 4830 6690 0. 1 15 5940 6695 0.035 4650 6696 0.043 4280 6713 0.051 4630 6714 0.052 4370 6720 0.031 4950 6725 0.076 4800 6726 0.030 4950 6731 0.034 5620 6737 0.090 4520 6744 0.056 5080 6761 0.067 4710 Continued on next page. . .

CT-0407 1050 229

TABLE 3 - MAXIMUM RELIEF ON CYLINDER ENDS (Continueo)

Cylinder From Highest Point to 90-Day Cylinder Lowest Maximum Relief Strength, (psi)

(inches) 6767 0.112 5850 6772 0.052 4990 6773 0.041 4780 6779 0.057 4970 6785 0.067 4830 6790 0.047 4700 6845 0.067 6010 CT-0407 1050 230

i TABLE 4 - CUBE COMPRESSION TESTS Southwark-Emery Machine (Ser. No. 57271)

January 30, 1979 Corrected 0-Day Corrected Minimum Load Cyli nder No. Area Iloight (in.) (1bs)

Sf [gth Strength (801) f fo[ tj Comments (sq.in.)

pgg) (Daniel (psi) data)

No Visible Defects 6527 4.00 2.03 28,800 -7,200 5,760 4,700 6534 4.18 1.90 34,700 0,301 6,640 4,660 6540 4.39 2.07 34,200 7,790 6,632 4,320 6540.II 4.06 2.20 20,300 6,970 5,576 4,320 6551 4.16 1.99 31,800 7,644 6,115 4,290 6599 3.98 2.02 31,400 7,889 6,311 4,110 6605 3.80 2.04 29,900 7,868 6,294 4,350 6659 4.20 2.03 37,300 0,000 7,104 5,390 6671 3.94 1.99 33,400 8,477 6,781 4,370 6603 3.37 2.09 22,500 5,677 5,341 4,990 Small area 6689 3.98 2.00 36,700 9,221 7,376 4,030 6689 II 3.66 2.00 33,000. 9,234 7,387 4,830 Small area 6690 4.18 1.99 41,600 9,952 7,961 5,940 67 14 4.24 2.03 35,600 8,396 6,716 4,370

__ 6761 4.08 1.91 32,000 0,039 6,431 4,710 CD 6785 4.35 2.01 36,800 8,460 6,768 4,830 ty3 6785 II 4.14 2.01 35,300 8,527 6,822 4,830 CD DJ II indicates second cube from given cylinder.

CM CT-0407

TABLE 4 - CUBE COMPRESSION TESTS (Continued)

Southwark-Emery Machine (Ser. No. 57271)

January 30, 1979 Corrected Corrected 90-Day Cyli nder Min imum Height Load' Sff((gth Strength g{fe gt! Comments No. Area (in.) (lbs) gpgt) (80%)

(Daniel (sq.in.) (psi) data)

Some Broken Corners and Edges (areas are corrected for these) 6527 II 3.99 1.98 31,400 7,870 6,296 4,700 2 Bottom Corners

(-0.25 in. 2) 6534 II 4.03 1.95 29,100 7,220 5,776 4,660 Possible Crack 6640 II 3.61 2.01 34,900 9,668 7,734 5,150 Bottom Edge

(-0.25 in.2) 6640- 3.86 2.01 34,300 0,886 7,108 5,150 Lower Edge

(-0.3 in. 2) 6683 II 3.08 1.89 27,600 8,961 7,168 4,990 Bottom Corner

(-0.25 in.2) 6690 II 3.92 .l.97 35,800 9,132 7,306 5,940 Dottom Edge

(-0.25 in.2) 6714 II 3.99 2.00 30,200 7,569 6,055 4,370 Lower Edge

(-0.25 in.2) 6731 4.01 2.03 37,300 9,302 7,442 5,620 Upper Corner

( 0.25 in.2)

[f3 6761 II 3.90 2.00 35,300 0,069 7,095 4,710 Lower Edge c3 (-0.2 in. 2)

Ave. 6,690 4,790 bJ S.D. 675 519 LN Cracked (not tested)

N 6550, 6767 CT-0407 i

TABLE 5 - UNIT WEIGIITS , ABSORPTIONS, AND AIR-VOID DATA Cube cube specific Unit Number V lume %

Cylinder Absor ption Percent Surface Spacing No.

Weight Percent Air V Id8/ Factor

• v0id8 - ll4 lbs/ft 3

of dry wt. inch (in.2/in.3) microns 6527 147.4 6.3 6527 II 145.6 6.2 6534 145.3 6.1 6534 II 146.7 6.5 6540 146.9 5.6 4.5 7.0 624 0.0065 52.0 6540 II 147.2 6.4 6546 146.6 5.6 5.0 7.0 563 0.007 52.0

, 6551 145.3 6.9 4.5 6.6 509 0.0075 52.7 6550 146.3 6.3 4.4 7.2 652 0.0065 52.7 6599 140.5 5.4 5.7 0.5 597 0.006 53.6 6605 146.6 6.2 6605 II 145.6 6.5 6606 146.6 5.0 4.6 4.9 424 0.010 65.8 6640 147.4 4.7 6648 II 147.5 4.9

__ 6659 145.9 5. 9- 5.9 8.8 600 0.0055 49.0 c3 6659 II 146.9 5.9 en 6671 146.7 5.6 4.0 6.7 682 0.007 5'4 .1 CD 6671 II 146.3 5.5 6683 144.4 5.2 bd 6683 II 145.1 5.4

[jj6689 150.0 5.5 6609 II 147.9 6.0 6690 148.3 5.2 6690 II 147.0 6.2 6696 144.8 6.0 5.1 6.4 506 0.000 55.6 6714 147.3 5.2 CT-0407 -

Continued on'next page. .

TABLE 5 - UNIT WEIGilTS, ABSORPTIONS, AND AIR-VOID DATA (Continued)

Cube be to W gl t Abs p lon Percent o{ds} S{ufae Spacing V lume &

YO Factor

• lbs/ft 3

of dry wt. inch (in.2/in.3) m rdns 6714 II 145.6 6.2 6731 147.6 5.8 6761 145.9 5.2 6761 II 148.1 6.2 6767 145.6 5.4 5.3 9.1 604 0.0055 50.3 6767 II 146.0 5.4 6705 145.6 5.0 5.0 0.2 657 0.006 40.3 6785 II 145.6 5.3

• 20 percent paste assumed

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cenpressien tests. 1050 237 C~-01.07

9 4

e e APPENDIX B CHDiICAL SERVICES REPORT

'O e

e O

1050 238

Chemical Services Repor,t  !

7 184I L P roj ec t No. : CT-0407 Date: February 26, 1979 Re: Wolf Creek Generating Station (Daniel International Corporation)

Our Chemical Services report details the results of tests for the cement contents and approximate water-cement ratios, of 11 samples of hardened concrete. Also included are the results of mortar cube cc=pressive strength tests obtained with four samples of Ash Grove Type II portland cement. The samples of cement and concrete were delivered personally to us on Decem-b er 13, 1978, by Mr. W. G. Eales of K. G. & E. Daniel /K. G. &

E. bave certified that concrete cylinder remnants, aggregates and cements are representative of the concrete and concrete materials used in the basemat. This work is intended to sup-plement that already performed relative to the strength of concrete placed in the Reactor Basemat.

Conclusions

1. The cement contents of all the samples of har'dened concrete we analyzed were at least comparable to that specified in the concrete mix design (564 lbs/yd3 ),

The actual range of determined values was 550 to 620 lbs/yd3,

2. No correlation was observed between the reported cylinder strengths and the determined cement content. .

3. In general, the aporoximate water-cement ratios (w/c) of the hardened concrete samples were below the level of 0.49 obtained from the concrete mix design. One sample (Specimen No. - 6551) showed a slightly higher value (w/c = 0.52) , but this was not considered significant.

4. In general, the cement contents and approximate water-cament ratios obtained with the latest samples of hardened concrete compare f avorably with those obtained from the previous set of samples (PCA report by J. J. Shideler to Daniel International dated April 19, 1978). These observations suggest concrete batching procedures produced a relatively uniform grade of concrete.

5. Tne compressive strength s of ASTM C-109 mortars made with the '.our sa=ples of Ash Grove Type II portland 1050 239

'l-

cement exceed the minimum strength requirements speci-fied in ASTM C-150 (Standard Specification for Portland

. Cement) through the age of seven days.

Results and Discussion A. Determination of Cement Contents and Approximate Water-Cement Ratlos of Hardened Concrete The cement contents and approximate water-cement ratios of 11 concrete cylinder remnants, identified as Nos. 6540, 6551, 6558, 6599, 6659, 6671, 6767, 6785, 6546, 6606, and 6696, were deter-mined. These specimens were recommended for such testing by Mr. W. R. Waugh, Consulting Engineer (consultant to K. G. & E.).

All the cylinder remnants, except Nos. 6659 represented concrete involved in the apparent low strength problem. Specimen Nos.

6659 and 6785 exhibited 90-day cylinder compressive strengths above the corresponding 28-day values. Spechnen Nos. 6558 and 6767 were especially of concern, because their 90-day average strengths apparently were less than the 28-day average strengths. Analyses were performed on three cylinder remnants (Nos. 6546, 6606, and 6696) using samples carefully selected from each. The remaining cylinder remnants were analyzed using the 2-inch cubes prepared from each by Dr. D. H. Campbell for his compressive strength determinations.

The cement contents of the concrete specimens were determined using the Sulfur Trioxide (S0 3) Method. The 503 level used to calculate the cament contents is an average value (2.09%)

obtained f rom chemical analyres performed on previously sup-plied samples of Ash Grove Type II portland cement (see again PCA report by J. J. Shideler dated April 19, 1978). These sam-ples represent the cement actually used in the Reactor Basemat '

concrete. The results of the tests are presented in the attached cement content analysis report by Ms. D. L. Glochowsky and Mr. A. A. Alonzo.

The results show the cement contents of all .the concrete cylinder remnants were comparable to, or slightly higher than, the quantity of cement specified in tb' reported mix design (564 lbs/yd 3). Two of the cylinder ramnants (Nos. 6546 and 6696} exhibited slightly high cement contents, 610 and 620 lbs/yd3, respectively, but they were not retested. The cement content of one cylinder remnant (No. 6599) appeared at first to be slightly lbw (initial test results given in paren-thesis), so it was- retested af ter preparation of a new and larger size sample. The retest showed the cement content was close to the proper amount. The anticipated accuracy of the cement content test, in this case, is + 30 lbs/yd 3, The amoroximate water-cement ratios of all but one of the 11 cylinder remnants were less tnan the level indicated in the 1050 240 concrete mix design (w/c = %0.49). Specimen No. 6551 exhibited a slightly higher value (w/c = 0.52), but this was not consid-ered significant with respect to "over-watering" (excessive re-tempering) of the concrete mix. The other w/c values ranged from 0.38 (Specimen No. 6606) to 0.47 (Specimen No. 6558).

Determination of the approximate water-cement ratios is considerably less precise than the determinatica of cement contents, because of other variables (concrete unit weight, absorption, and cement content and absorptica of aggregates) .

A comparison of the cement content and approximate water-cement ratio values with reported cylinder compressive strengths revealed that no direct relationship could be established.

There were no significant differences observed between the higher strength and the lower strength cylinder remnants with respect to cement content and water-cement ratio.

B. Determination of Compressive Strength (ASTM C-109)

Four samples of Ash Grove Type II portland cement, identified as C-UT-15, C-UT-18, C-UT-20, and C-UT-21, are currently under test to determine mortar compressive strength according to ASTM C-109 (Standard Test Method for Compressive Strength of Hydraulic Cement Mortars). The purpose is to ascertain whether or not these samples comply with the strength requirements specified for a Type II portland cement in ASTM C-150 (Physical Requirements) .

The test results , which are reported as average values repre-senting three individual tests in each case, are given in the table below. For purposes of comparison, the appropriate ASTM C-150 strength requirements also are shown in the table. An -

extra 2-inch cube from each cement sample is available for testing at some later date should that prove desirable.

Cement Sample Comoressive strength, psi (ASTM C-109) 3 Days 7 Days 28 Days C-UT-15 2460 3565 5365 C-UT-18 2485 3390 5340 C-UT-20 2035 2885 5015 C-UT-21 2290 3315 5400 (ASTM C150-78) 1500 2500 4000 These data show all four cement samples have surpassed the mini-mum strength requirements specified in ASTM C150-78 (Physical Requirements) for a Type II portland cement through the age of 28 6 ys. It is our understanding that the cement to be used in this 'roject needed only to comply with the less stringent ASTM C150-74 strength requirements for a moderate heat of hydration 1050 241 Type II portland cement (based upon chemical limitation) . The sample identified as C-UT-20 is somewhat lower in strength than the others.

f. M L. M. Meyer, Manager Technical Services Section LMM/md .

CT-0407 .

Copy to-J. J. Shideler L. M. Meyer A. A. Alonzo/D. L. Glochowsky 1050 242 Page 1 of 4 Project No.: CT-0407 Completion Date: 2 13 79 Sulfur Trioxide (SO ) Method 3

Concrete Cylinder No.: 6540 6546 6551 Cement content, lbs/yd 8: 575 .

-610 -

560

% SO: (oven dry weight basis): -

0.32 0.34- 0.32 Unit Weight, lbs/ft8: -

S.S.D. . 147.1 146.6 145.3 Oven Dry (6 105'C) - 138.7 138.8 136.0 Free. water content, %: _ 5.i 5.3 . . 6.4 (S.S.D. weight basis) -

Combined water content, %: 1.8 1.9 2.1 (Oven dry weight basis)

Total water, lbs/yd ': 8 295 280 330 (Free water + combined water)

. Approximate W/C: 0.44 0.39 0.52 (Corrected for aggregate absorption)

Total dry aggregate, lbs/ yds: 3100 3070 3035 Comments:

(1) Concretu and aggregate SO: contents determined gravimetrically in duplicate (modification of ASTM Cll4). Aggregate SO: content was negligible.

(2) Cement SO: content 2.09% (average of Type II Portland Cement samples C-UT-16 and 17) .

(3) Overall aggregate absorption 1.25% (average absorption of a -

50/50 C.A. to F. A. mix with respective absorption values of 1.8% and 0.7%).

1050 243

.} t Page 2 of 4 U us t U ll U I11) L, CEMENT CONTENT Project No.: CT-0407 Completion Date: 2/13/79 Sulfur Trioxide (SO ) Method 3

Concrete Cylinder No.: 6558 6599 6606 Cement content, lbs/yd 8: 570 550 (510) 580

% SO3 (oven dry weight basis): 0.32 0.31 (0.2 8) - -

0.32 Unit Weight, lbs/**8- -

S.S.D. -

, 146.3 145.6 (148.5) 146.6 oven Dry (0 105*C) - 137.5 137.6 (142.0) 139.7 Free water content, %: 6.0 5.5 (4.4) 4.7 (S.S.D. weight basis) -

Combined water content, %: 2.0 1.8 (1.8) 2.0 (Oven dry weight basis)

Total water, lbs/yd 8 : 310 285 ('24 5 ) 260 (Free dater + combined -

water) ._

Approximate W/C: 0.47 0.45 (0. 39 ) 0.38 (Corrected for aggregat,e absorption) .

Total dry aggregate, lbs/yd 8 : 3070 3095 (3255) 3120 Comments: _.

(See Page 1) 1050 244

, , Page 3 of 4 s UUs Ull UJI11"LL CEMENT CONTENT Project No.: CT-0407 Completion Date: 2/13/79 Sulfur Trioxide (sos) Method Concrete Cylinder No.: 6659 6671 6696

~

Cement content, lbs/yd 3: 555 555 620

% SO3 (oven dry weight basis): 0.31 0.31 0.35 Unit Weight, lbs/ft 3:

S.S.D. -

146.4 146.5 144.8 Oven' Dry (@ 105'C) -

138.2 138.7 136.7 Free water content, %: 5.6 5.3 5.6 (S.S.D. weight basis)'

Combined water content, %: 1.7 1.7 1.8 (Oven dry weight basis)

Total water, lbs/yd 3: 285 275' 285 (Free water + combined water)

. Approximate W/C: 0.44 0.42 0.40 (Corrected for aggregate absorption)

Total dry aggregate, lbs/yd 3 : 3115 3125 . 3005 Comments: '

(See Page 1) 1050 245

Page 4 of 4

" UlllUI CEMENT CONTENT .

Project No.: CT-0407 . Completion Date: 2/13/79 Sulfur Trioxide (SO ) Method 3

Concrete Cylinder No.: 6767 6785

^

Cement content, lbs/yd*: 570 560

% SO3 (oven dry weight basis): 0.32 0.31 Unit Weicht, lbs/ft8:

S.S.D. -

145.8 147.2 Oven Dry (@ 105'C) -

138.4 139.5 Free water content,..%: 5.1 5.2 (S.S.D. weight basis)' -

Co=bined water content, t: 1.7 1.7 (Oven d:.91 weight basis)

Total water, lbs/yd 8: 265 270 (Free water + combined water)

Approximate W/C: 0.39 0.41 (Corrected for aggregate absorption)

Total dry aggregate, lbs/yd 3: 3100 3145 Comments:  :

(See Page 1) 0W d . d. .hWho D. L. Glochowsky A. A. Alonzo u Assistant Research Chemist Associate Research Chemist 1050 246

APPENDIX C BIBLIOGRAPHY No. 231 "EFFECT OF SIZE AND SHAPE OF SPECIMEN ON THE COMPRESSIVE STRENGTH OF CONCRETE" T

1050 247

ggggggggqlng u2a o,a ccen ,e n ,a. Su.w.. un 1, won . an. c 2,2nsu2ao teehnolegg EQb@fCIOflC# i

...._ _ _ _ P00R ORGINnt EFFECT OF SIZ'I AND SHAPE OF SPEC'afEN ON THE COMPP'.SSIVE STRENGTg ri CONCRETE 10./; 1976 LDf1TED BIBLIOGRAPHY NO. 231 By Joseph J. Shideler Director of Administrative and Technical Services and Marilynn LaSalle Librarian February 19, 1979 CONSTRUCTION TECHNOLOGY IABORATORIES R&D Library 1050 248

, y. .._s ._ ,. ..._......-..;........s.

P00R ORT

...<-.,_s..,.;..,...,..,;.

M g.39_. .;:,

,.y M

1976 j;.m. L/ A-2.

Pamphlee Serial File - h-

.in,. Anon.

4,x .Y.

~ Concrete Core Testing for Strenzth * '

~

$ Ct. Brit., Concrete Society Technical Riport No.11, 44pp (1976)

MJ. c'1JKeywords: ..

Q f,q reco:nmended procedures; cIompression tests; concreta .~

t, cores; samples; test procedures; cores; ^'

Concrete Society T.R. No,11 i ga.

p .

Q 'Ihis report provides recoc r -fed procedures for obtaining and the '

g coc:pressive testing of concrete cores and for the interpretatic'n $

h of the results. Evidence from pzaatice and research is provided i g$. for ~t he forculae and conversion factors reconnended. '

ad 4

N J Z j (de e e c ~rs ? e .; +

RP-1-6-1 AM-42-2 hW [p' 5/20/77 - 886 - mt h

,{

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$$$W.YWCS=$NN $ NI.nE:dsfi5AS'~EC. 2 S5 v

.=:n: m-e-::.L n M w n - M W - M yp2 et*~~:; w a % 3- w *x w :+ W m wg;.

.n .

p 4;;..>

N 1975 M"O~ '

Fa=phiat Pa=phiet Fila h (Faggett, Edvard) { ~~

j Faggett, Edward g;

e... Deter =ination of the Relative Co=oressive Strenrth of Concrete Fd.i.

S. Cores of various Sizes and the 6" x 12" S**"dard Test Cylinder Texas, Univ of Texas. Thesis. 116 pp (1975) %e

-)3

. 1:;

Ma Keywords: co=pressive strength; cylinders; spec 4-= M.;

4 *,

By atte=pting to control all other variables such as capping of f 3 specimens, curing conditions, Was ti

ne, apecimens' moisture 2 -

condition during load testing etc., this research was intended ;p j$ to provide information on the core size to strength relationship. j

$? Stre=gth correction fanto: s were deter ^ad. y

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_ 1050 249 h

P00Rg,. ORRINAL g

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au -+ - -u.: , u.. - nn:.gmg. gy, u,.g33gy.

x .3 Q '

%y.4 N 1974 (4 A ~O-1 Pamphlet Pa=phlet File V llQ 9 (LoPez, Robert V.) h3 3 Lopes, Robert v.

g Apparent Coc:oressive Streneth of CNerete Cvlinders as Related to Soecimen Size. . ' .  %

d , ,

E Texas, Univ. of Texas at' Arlington. Thesis.' lOl'pp (19.74) N-p:

s% .

Keywords: con:pressive strength; specinens; cylinders ~

y -

7 S ,

..e . ,

C By testing 30 cylinders of 3 different sizes for a given design y@ strength, and statistically validating the apparent concrete .

5

$ strength for each size-design strength, correction factors are }$

established for concrete strengths of 3" x 6" and 4" x 8"

$ cylinders.  :~-

These correction factors c.ay then be applied to con- i

]M pressive test results of these cylinder sizes to establish a [

correlation with tne standard 6" x 12" cylinde=. f Ph.i E-d AM-42-2 AH-40a  %

[2

% 2/13/76 - 359 - mt M to

-m c

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1972 4 W- 4' *. Pa=phlet seriel File

&W m

? @

4 Lewis, R.K. n > -

3 The Cc==essive Strens;th of Concrete Ceres. Ys

/3 Australia, CSIRO, Dept. 31d6. Res. Report L-18, 34pp (1972). 'S u

&s Tests have been done en the~ cc=rmison of concrete cores of $g iy various diameters with standard concrete cylinbrs. The results W 3 confirm that the ec=pressive strength of cores frc= vell-cured 3

% concrete slabs is less than the strength obtai ed frcn the gy h standard cy'4 ders. The variation in ec:pressive strength cf $

concrete cores is also greater t% " in cast cylind**s, but the hi_

5 3 variation in ccre strengths was not related to the diameter. ,

m 4

i AM-42-2 E

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4/5/74 - 744 - =t n g

a =P s s d S...

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k 1972 O O ' N " Pa=phlet'-f Serial File p .

y; 2 ?cceroy, C.D. . E y The E*fect of Curi-g Conditions and Cube Site on the C::unh4 g b y Strenrth of Ccncrete. ..

.. :c yd

,e Gt. Erit., C&CA Te< %4 cal Report 42.470',16pp (Juy 1972).~;* 5-

.s m :.. -

ca 1 L.. -

., . S

] Cubes frcrs 50 to 150 2:::s were used. ?cr vet-cured specimens, there h q is a subste.utial decrease in ernak4 g stren6th as the cube size @

g is increased for the strc=6est ni:::es used. The dr/2.g history 5 es is shavn to affect the size relat6caships: pre--ture d W of $

] c=all cubes before hydration has progressed far, 7 4-dts the @

g stre:gth develop::ent and reduces the strength as surface cracks 5 g are for=ed. The result is that s=all cubes are up to 20% vesker --

R w than la.e~ e ones. 5a

,4 n

+.

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@tr 11/14/72-1353-nt 2

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Periodies1 ku

.q -

5 ,

T2 Levandovski, R. . kf '

d R-lationshit Betveen Cylinder and Cube Ccx:: ressive Strenrths of M i Ce=ent (In Ger=:an s-ith Ecglish Abu wet.) J.:

lj Betenstein zeitung 32 (9) 562-566 (sept.1971). f.j c

p N Wat relationship is there between the strengths ascertained of  ![

C test cf d da-s of r*,Am d*,mensicas and the cube ecz::gressive L ea it; strength of concrete? Ch test cyldn' s of the slenderness h/d = M

$ 1.0, the cube ccepressive strength cra be deterinea direct, pro- s d vided the cyldna*= dis =eter is & = 15 c=; on specine=s of d = 10 j,;

N c are found values which are by apprc:r 5% above the effective j

'h s=trength. Even under u= favorable conditiccs, the eenversion y

~

N facters deter. ined ellov sufficie=tly correct state::ents fer fiaV y.

M a:plications. t

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AM-42:4-J

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1050 251

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g 1970 /rM- $ ' 1- >

Periodica1 ..

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r,

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h, ^au11etin Du ci=est 38 (3) 1-4 (March 1970). J..  :/ . b.. .. . t <

y . , % -3 M . . ' ' . ^ . ;- k .-: .

^

Fig. 1.

,i-Cc=parison of_cc=pressive strength of 3 cm dies

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@ j

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o% psww.w w: -m-;.-~ :w , -v.>=

.- m-m ~ -wp;d.n.% p

.s p;i h

are 1969 AM- Ka-1 Periodical %4 L '

M*4-4 ger, R. C. Q*

'S I*fect of the Cc e Din =eter on the "w.nured Strencth of E,,,

e cen=r-te. m srisiss) -

si aee_s:a Mrc 2 (3a) 34-69 (xay/- 969). [

k A 16-in.-deep slab a=d a 16-in. .,h2c1 vall vare constructed, 5 j:$ meist-ci .ed fcr 3 months, a then ec cd to obtain 2,4, ani 6 in.- y j dia. specimens. 'Ehe 16-in.-1c=g con: vere sawed dnto 2 by E, 4 by $ .

~

@j S esi 6 by 12 in. specine=s fer e==pressica tests- e of the 5

.'s ceres v .re seeked in rater,40 to W h; the others vere 4 ersed  :~c I:j fer 23 days before testing. Also 4-in.-die =eter , cores ve e U"ed 3 .

10 in. i= e the ,ran sper

• en and brcken cut; the resu1t'=g ccres 3

@dn.

vere te_r.=ed to E by 8 is., scehed 40.to 4 h, cud then tested 4-

e. , in cm essien. Heithe.r the difference in ccre sizo ner the + .

.;. . bran'" I cut cf cores effected the reasured strength siE- '*ir -"tly. Y:

m

, . =_

. x AM-h2-2 2 3=-

@ s/2s/69-256s=: +

m

h. , ,, . nMm.c.ummuwwmamame. usa.. =k, .

1050 252

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P00R~0R E L s --

ti.- w ~- x. ..e w.-p.ygg>eg ,. .

1967 ,4 74, gf7, Periodical 693 303 346 s 9 .  ;

-s Albrecht* W. - -

n -

y

b. '~re E*fect c' the Relatir- +'s of Sa==le Thir1-ess to M-rdm:n

's

,4 Pr.rticle Die =eter c=d the Effect Size of Sa= ele en tht. Cc=:ressive j di Strenzth of Concrete. -

Q 3r:cs: Eerste11u=g Veiva-d"- g g (3) 173-178 (May 1967) (In Ge: .n .

Q

-3 ".th E=glish su: es:y). , , , , , , ,. . . . . . p

. . _ - . . - ~

m$ . In the evaluatica cf Ws on teste and in the testing ca concrete Q is taken frca structures, in v' ich test pieces necesse.d.ly occur,in

% varicus sizes and fo:=s, the e*fect of the size of se=ple en the. ]!

~

? stre:gth =ust be taken into accou=t. In se=ples taken frc= struc- &

M, tures the relatio: ship of the ss=ple thi+~ss to the largest part- i G icle die =eter is eften extre=ely <---11 The effect of this ratio k

$?,; on the c=::pressive strength is to be taken into account. The cube  :;

b.s so fer preM~d"ted as the se=ple shspe for ec=pressive s'e-.sth 'E

'A testi:g but the cylindrical shape with various diameters is gr*,4-- I l3 in i=pertar.ce. The general use of cy14~'ers for the proof cf 7,'

5 strec"' th cust, therefore/ elso be keet ~

in ~*"4. E 5s AM-42-2 2430- I

1. ~37-1 I@r:..- . 6/30/67 .i N, F.! h=f4 M 3 Yi C E N W 0 9 M B $ % E SIf 2 5iE:hi$357545~-5.9G555 WP

_ $.% .- N- *e. **  % - . _ **

4

x. %w.,.

[h! 1967 A y , v3. ,,,. Periedical c 691.305 'Am3 3.1 y -

n -

Yc E : rgave, Jite=dra K. t2

$ Disntssian ef:"A Ge::eral Reis'*m fer St:m-ths of C=cerete Smeet.-

3 ce*- c:f Differtet SFA.xs and Sices,." by A. M. Nav' 11e. '

{ij!

J. A=. Cc=:r. Inst., Pro =. n (6) [Pt.2j 1%1-l%) (3uce,1967).

r3 {

gi -

DE. An'.2=r has used a value c* O.91, taken from ASIM Standard C k2-64 -

.y in arrivir.g =t a fscter of 0.83 for ec=rimrting the s'%-th cf n k 3 6 x 12-in. cylinder to that cf a 6-in. cube. This is cet e=e -  :

g in the ; resect case be em:(1) t& ASnt. v=lue is fer r eWs al-

~

S leves:e for the ratio et length to dian c:f drilled cores, vben - I

[$ 0~2 len5th-diam. retic is coe;(2) these eceffs. e.1,a not valid for'

~

'y% dry c:= crete, which eny differ;.eocsidera'.ly...The reletten between cylinier esd cuba.stre=Cths els.o depeeds co the st:ength level cf 5

% to: ec= : eta. Ae:crding to 1"Ee.r. '.t's for=ula, used by the -

M C thers the eccVersico fe:ter can very fr::n 0 76 to 0.86 over -

1 y tha raegs cf eccereta st.c=gths fres 3000 psi. to 8500 pai. . ,

J'.0 (Abstr. hy }c)

• AM D2-2 -

I 0-$ CM-1-1-2 -

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.: g 4.# t -

. y; 2 .

un .

4 Ce=pbell, Rir 5 mi H. acd Tobi=, Robert 2. . - .. .../. :... 1 Si Core e=1 Cy1Nar Strensiths of Naturel *'A lim-'tes!ght CEE[mte. 3 Q

n J. A=.

Concr. Inst., Proc. g @) 190-1% pyr.19o7.)._. ,.. _. ;

5 s

. ^. - ' . - .

- . '- . . ~k i qi ), ' . w.- ?.- ,,: Ba ~=T, .

f. .'

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-, ~

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g._ The ev psssive strength of lab. cured a=d field'eureicy1*M_ers k

=

y . are compared with y Necrly 500 sa- "-=4ofand =atural6 in. e=d dian.lightweight cores at ages up to 84 deys.

coccretetunder. .- ~ L h

~~

si=ulated . job ccnditic=s aboved that all cares at comparable ~_ . j -

1.p ages tested lower th .n cy1*M-n. - -

J W .

S;

. y.-m n@ =

-3  ;

m. -

3

• 3 Ag-5-3 R4 E2 -

is 6

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$" 1967 AM-42-A

'+

9 . Periodical 4 E-3 Fineiro, Heises; Ja s, Jose; Valensuela, Sergio e=i Genta, Jose Cemressive Strens;th of Cencrete-Relationship Between cylindriesl y ' -

M.r E

? mmd Cubical.Stre=gth. (IN SPAhT.SE). t D}

m Revista del Idie= 6 (3) 141-156 (Dece=ber 1967).

'1 *

$ In crder to study the.r:lah;ie'p between cylindrieni a=d cubical ,D:

N strength for conditic=s of =cre practical interest, the followi=g  ;

9 factors vere consider'ed: nat=e of ege N,.t e , -= + - size, age p_

,g-and type of ce=e=t. Statistical analysis showed.th.t those facters vere not siWicently i=portant. A relatienship is preposed

}

4

'3 .

betseen cylincrical and cubical strength censisti=g of two i=ter- g

$ secting st-aignth lines: the first ene Re 1,,,= 0.86 3 cub, up to kg/c=2 cubical stre=gth, a~* above 403 Sg c=', Reyl = 0. "

$ 'd

,b + p$

?O 152. The recults of sc=e other i=vestigators are ==Cy.-  :;;g ks AM-k2-2'* - $,

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.3 ."a_hics, Sander (Pref., Lept. Civ. Eng., Aubu:r.1 Univ.) k g Relatic:s 3etween Vericus Stren:;ths of Concrete. $

~4 D

Eighway Resecre Boerd. -SecordHo.210pp.67-94(1967).

. . , JG . . :k

• 31-3 Analysis of published experi= ental data shows certain ec=ela. N'%

3 tions between cyl4*A-r, cube, and c;odified cube strength; $

q between co=pressive, fle:r.:ral, direct tensile, and splitti=g g hj stre=Sths; and betwees torsion, shear, and other stre=sths. W p Por=ulas related to these co=elatio:s are discu.ssed. Howeveri ji their 5::eral cyplication rec.: ires cautien because they would cat 5 4.

.-} necessarily hold for testa carried out t:=dt.: differe=t co=ditic=s. $

m  :-

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fe. 1965 A M . v.7,. 2, Feriodical n- 691305 A=3 w%.

a .

k a' 2,

.; rm111e, u m u. -

3 5 a A General s u s a1 st:as. Relatics far Stren ths f Com re'~~ Smci: secs of Diffu. mt L

,h J. A=.

e

- Comer. wt., Proc. Q (10) 1095 mO (Oct.1966). $,

Y.

-a N..

,g It is abovn th=t the strer.sths of c.mmte test spec 5 m (cy11s. -

y g ders, cubes, n=d pris:s) can be reinted to one another by .si=ple -j J,5 exprtnsio=s. Subste=ti '* s test results. cre presented. Be  ?

g secondary da"hr.nce of the fineness =odulus of egg:ep on this y 4 reln.tio! iS discussed. U 1 .

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g C===:ete Stre==th Mansure=ent ' - Cores Versus Cy1*- h s. -

Q A.S.T.M s Proc. 5 pp.co3-OSO [vith c11sc.J (19o3). . . :.7 -r E '

M Nat'1. Sand.& Gravel is dat'1. Reedy Mix. Con =r. Ass =. JRL Publ.15 3:

M P.. Ws.2ive strength tests .re.re -*-la ec=parh' Wha cy7 ham 1:

N, with cores dr*'7 ed :Eren u_ el-size, al-ta of the seme cc:s i

$ ., crate. Vezinhies i==1uded: con :=tes.lmsde with 3 types of eggre h

7* - g=tes, *~N't c=i por field curing, ' flat n7 ek= cored vertical - 5

. ;ly =nd colu=ns cored h=.-1:csta117, specims locati=n, ==d treet. 5

~

h,(. ===t c=d =se of specimn...Cc

es drilled =t 91 days ed tested in

• Cr#-~ e with AS2M Heth:ds C 42 b=d strengths 10 to h0% 1c.cr 3 g- thun 'ded cyid- 4-s der *"dd g cn type of specimen, curl =g ==i

}

Q other fc=tw . Soaki=g cores ES hr pricr to testing did =ot in- E

]

pr== n o. w.t with cy'*-a--s. Cores dried f== 7 d=ys g=ve th:

best inite= tion of in-situ centrete stredsth... Strength of cylis-

)

i ccrs cu: ed for 2: c':rJz US eleted veil vi,,: ='.r-dr.*co core speci- A i

M;;; ren: a:"M cf ct E1 . '.cy=. 7~ , =cidad cyl:'.::.icrs c = :i to si ..:lete [.

y cc:iithms is c:ncret =tr.::mrcs ==y b= u=ed to indiente  :=rir==. <

m .::s .1_::ffcci: cu st:...g;th-. S tend 6-e . e.' . c--l'.=Cc- = c: e rf.3 , f M- : .itrJ:.l.: . .;r c::ec , t :nce tests .

. .91:!2-2 . . . 2*il' /66 *: ; $

s.

'br,f5%?%% ~%WM u-=DW5 t:'-E-%#5'3;%CCi;ich,'MMM WJ.di'-% bi&-&

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mu

'h 1955 A P1 . s -' -

peric.Y.c=1 691 305 h3 heb -

.$.4 - ~ 7..

Ecghes, 3.P. b %%~rd an, 3. 5 Cube Tests a=d the ""4 s"-d'a7 E

Ei C===ressive Stre=:sth of Ccrr d.c

$, Mass =ine of Cc=irete Research, E(53) pp.177,.2f:2 m n. (Degt=:bcr 1563} $..

. ~ . v.

3 L 5/6/66- 15o0 d The c=le is u=d:nbtedly the most conve=ie=t speci=en to use v5.en . i M large "- kans of crushi=g tests are requi -ed for ecocrete e=:rtrol Z

4 pt.-poses:- The cyl* *, or prim, on the other had can give n. 7.-

-k batter esti= ate of the W d' e g essive m g .h of- y '-

-;f3 con =::ete.

• paper shovs that variable diffe.rences can occu::-

$ between the cube ern=%',3 strength and n -Wa7 r cr-- essive - -

M .: %-th, a=d then indicates hov these Ad*ferences can be  ?.

3

- great 2y -+ M ed by a s=1tehle e- .** *1catics of the testi=g j 5 te 54dque. ". ts cd=ple modificatics to the, enbe test --%1as

- s fi$ the *e--*cl w %th to be deta:--*--d very :-=^"'y. Se

...t.6-ly cc=v==1ent cube cpeci es crn therefore =cw be used fc

. t- ':=ial cc:;;:nceive at: e::sth detemi=stic=s c= va21 as fc--

?

~

D  : r- ' cc= tral p.::poece. T.m . : . i: ned use of '.12 cube cs

% ".7 e : e..dr_- d rc:::: c: tc=t :: ::':;.:.. : t.hcr: fore Oca .:::e6. t 2Aih

.4?.2.y.=. +. v.?:=;-r tw.m~:. >= . n:-- =.=-~=r -a . ~.~=

- ~ - .=- "

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_ ,_ 1050 256

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w m . - - -_ - : -_ w . - . . .~r: u :

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c. \ ge,w-Feriodical -ex

,h 1965, p, 4 g9.<> 691.06 B45 {C 4 ... . .. -

g h- Bad"m^-an,' Sri S.

{

P E*fect of the Size of the Soeci=:en on the Cc=:ressive Strar-th of .*

d w ce===ete.

• g

. . w.= , . .... ~. - . .

E R.I.L.E.E. Bull. 26, p .81-83 (Mar.'1965). I2 g .

y 1.. .

v h Cubas of 4" and 6" as well as cy14"A--s 6" dian. X 12" height cre $

-i c<- '1y ado :ted for conducting cA cssive strength test on con-3-  %

crete.. .The phys. chsracteristica .of fine a=d coarse aggre5 ate as I-3 vell es the grading e % -ts are given... Table 4: Showing the ste-g dard deviation and coeff. of veristion of test results...Conclu-i

$ stor.: the size of the specinen affects the co=pressive strength of %E y _ ecnerete, the general tre:;d being that the recorded strength of 3 3 the cube is len.ered by about 4% for every 2 in. increase in size .I

..'n sterti:0 fTn 4" cube enva:ds.

9 t

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4 w .9 ta 1962 j g g ,g ?ericiical 691.06 R43 S Ecssen, Z., KiC ->nd, /.. , Nielses, E.3.C . and '7,'"1_ws, S .

E B,i C.7:s:sive Strength of Cc crete - Cube cr Cvlinder?

4 w RILD3. Dulletin (17) 23-30 (Dec.1962). ,  ;

LT3 E y *'n hen '431 in 1956, and the Ccnite Su opeen du 3eton, in 1937, 7

).3 resolved to give preference to the cyld- d-- for research tests I pH of concrete, the fi-st i=portant step vas taken to;.crd intro- s 3

,;i.i

• • "-in_ en u=iversal test. shape fcr concrete tests. In this article the cathes have reviewed.the varicus facters by which -

9; c'.:bes e.ni eylinders :::ey be judged. The authors e,~.,.2 tend t!.at q cylinde s should be preferred for cc= rete testin:;, for ressc=3 p;

lis .ei in the article. '.

4 -

M gE's -

AH-42-2 (4 II

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% Dse, Inge and Johansen, Pr-w'- '

1..t .. .%. #

M An I=restigation en the Rah'* +4 3 k Strengths of Co==retec <. .9 3etzteen the Cube ". A Cyli' A- - . E -

g N. .--!f'

~

R.I.L.E.M. Sulletin. (14) ~125-153 (Par.1962). ~ . * . . ;- bi h 4 . . . .r m . _.: . . - - - - -

g _ ,

Sis investigatics presents the results of ch:st 850 tests of ec=cre1 $

cubes and cy'4-d- s. Every precautics vas.taken fer . securing direct g

g c--g-isen betarem the various sizes and skapes of the test speci. h ,/

g, n*ns. De results sh::7. red that vi'S* ' the field of this i .ves*@- 6

~

7.g tion the size of the test speci= ens did not have a::7 effec

• um the t g; stre:gth, and that the cyld-A stre:.sth (standard vertical cy14-dam:di g

3 vas ebent 86% of the cube strength fer all the differe=t strc=gths og e C2*'. rete.

Sere is tW ., no rensen rer pre;cz one g g

'y c. ,ast spe-1:en for ancther c=e as far as strength results are cen. 5 W cernea, but one shape (the cube) =.sy ksve ec=sia.-chle practical 9 Qw c:~entages in the fia'A as v=11 as in the 1 berateries.

6

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.$w-a 1962 AM-G Periodical 691 305 M 5 %4 ..

3 Petersons, Nils ,

y 5 Relatics Between Strengths of 15 en Cubes .e=115 I 30 Cyli=ders. 71 T3 (7H SiiEDISH, vith M4 au su::c=ry) E Q Nordish Bete =g 6 (2) 159-170 (1962).

y; r -

.g 3 '

I An account is 51vpn of the results obteined in strength tests en 9 I:5 k 15 c= cubes and 15'x To en cyl1=ders. Both cube e=d cyli::aer spee- j

.I 4--"s were unde on ec=

rete taken from the se=e batch *"4 cest-in 3

.a -

3 steel : olds, v'ich vere provided with flat-s cu=d end plates and g .

f.u partition plates. St:essth ce=sistency end cur 4=g ceniitic=s of the concrete vere varied. Test results vere sub:itted to a stctis- :.

f v ,-

.W., tical n=alysis...when the strength was high, but elso when it ves j-6 cc=peratively lov, the cenversion factor for reducing the cyli= der + -

iq strength to the cube str_ngth ver.* ed d. thin vid= ' d-f ts depe= ding' f g en the cethod of treat ===t of test specime.ns. For the seeze ,e eie J of co=: rete, the differences in the observed values of the ulti- y y's

. =ste strength ces be e.s high cs 25%.. . Tests also shoved that the * '

~-t ec=pressive strength of 15 en cubes ex.hibited a dts7 ::ics which ~

~'"

v=s sis =1ficently s-'iler than that observed in the c=se of 15 vi: X 30 c= cy11=ders. . .elso the 15 en cube: cre si==ler to cehe

~ i'

. .-en, end to hs=dle. AM k2-2 . . 8/8/62 y ss .w. .. w . m w w w . - - - r= - .. - ~

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g 1960 f: H 'y.) - 2. ,Pe-iodical . 691303 n73  %

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+

~

5 h-=en, Henry; Kiel'a-4, A.vid; Eielsen, X:2nd E. C. and -

j  % 7 %, syen . .. ,

(.;. n ; . c. -' . . .

E

$ C= cressive Stren..,th of Oc= crete - Cube er Cyld-A-? -

A

?4 sordish 3ete=g M 305-320 (19eo). (Is scau.As,vith 2:n;1.. t

~

M su=s.) f-d $. A review of the pros and cens of the t:ro types of test speci-. E 3 'r. ens, cubes end cyld"'- s, concludes that friction betaees {

n the loaddag surfaces is the prd---'y cause of the varying re- . :t

.laticsship between cube a ' cy'd a - stre=gth. "-*s relation. $

['g

. .is also effected by defwticas in the heads of the tas'".=g j k m-S' e. Ecirever, both sources cf error can be ald--*"eted. e Frictic: can be ceu= tere =ted by M-*-- the spead~ .suffi - $

5,M 'ciently tall (h/d = 2.0); test head errors ces be croided f; 5 .by *d-- the hecis su.*f.*ciently rigid. Adrsstages of cylin- i

q. ce spe:w- cre e=-- _-:ea. 29 re erences. s; u

s J.

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j Conente

• Centrol Tests es a Measure of the Prc:>erties of Concrete. fp Qj Great, __--1t ain . Cement & Concrete Assn. Sy=p. on Concrete Quality, G 19pp. e r5 h yt.n...e f(n=v.1964). r e

g Fed. ors effectd=g defor=stion and failure of concrete co=pressics E

-g speed--ns show that the cuba and cylinder strengths are strongly y

{g. dependent on the state of stress induced in the specimen, its size 3 g and co=dition a=d the meth:>i of applyi=g the load...results from i

.$ the stn 4-d control [ tests are co= pared with data obtained from }

j$

exsre f =2de= ental tests under t'

'a edal and co= plex states of stress.

3 Cc=pressics tests en cylindern and pris=s, vith a ratio of heieM. E

'Q to dic=., or to vidth, gre: der then about 2j, are direct censures . .

p of. the unicxial co=pressive strength of en--- ete, rherees cube tests. t g are a censure cere of the resistence of concrete to tricxial cc=- $

g pressica. The cylinder splitting test is a direct nessure of the g "-*--del ter.:ic: strength whi.le he fler.:ral bec= test gives en in- "

dicatics of the fler.:rcl tensics strength of con mte...

(q.?pg (exte: ive data] AMkCa,AWh2-2..1/6/63h3 4

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- y 3

5., 'lhe ?"~"* ==tal Lavs Gove:: d - the Infl"---e of- Size and Vnit---

(m oms) v

? g e of ce== rete se--=s fcr ce=ressic= nsts.-

c oest. z= gen.-Arch. Im p/2) 22-w (1re4). Abstr. in Ay31. need. - .

r, .

nevs.,18 (4) Abst:::- r.o. 2137 (A--d' 1965).: --::ce .. '.

w M .-

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R M A ' great "--N:: of test se=1es 15:rs the literature are ec=: pared by - 3 O plot:i=g the ec=:p:sssive M.-qhs er**"4 the vo'-a of the. test ' 3 spe " e , usi=g logar1+'-*c scales alc=g both axis. A relatively - 7.

L v 4 c 2 veln=e 4 "v-e-is 4-d* cated. A general discussics is  : C 9 given cr--er 'ag the d "'"_nce of the size, the degree of harden- -

G

] i=g and the type of come: rete en the d add rated. tre=d. .

Os vi c, 1 '

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V M.

M ce 1963

.s s. n . >

Periodicel _

-CL -f -?53n ,

$J3 i:'d W, --

y, Wagner, W. K. .

(S,, E*"est of Se== ling and Job Curim.:; Procedures en Cc=pressive g

, ' .'ij S ren:; h of Cocerete. . 9 fi Materials Res . & S--"'*- .".a 3 (8)'629-634 (Aug. 1963). {

mes . .

c

~,.

w . t

] M::re '5 -" 1700 field c =pressive strength . test vere e@:ed ove . {

'i M a period of 8 years on no-da-1 30CO-;si concrete of 2 aggres=te ,.

9 . sizes. Co=parisons of contractor - de cylinders with leb.-nede% 5 g L by' d ' rs ab:nr t.bs.t values reported on con = rete itproperly se= pled, f

! v,, . cureds -

• tested een cause c==siderable doubt as to the cu 11tvs of t (2'; the product. Other test data, coveri=g a period of 16 months, ces- i results of 6- = 12-in. cy' d ~ia-s at 7 -~1 28 days with a d

@A h- x 8-9: 'dic=cni drd '7 ed cores taken f. a the sa~- concrete after pere the,E. I h 23 dzys'of field cri.=g. I= this specific cese the core strer.gths C vere ce=sistently b?lov these c' the cyli.uiers at ep;rox. the sc=e 2; uN t%

ag-~ '"'-- 2 sets of test data r*-,-mtrate the "=.~~-tance of proper f

} ca=p'.ing c=i curing of fieli speci=ers for reelistic evalustics of 1 3

the test results. AM-22-3, AM-42-2 i-

+..s '. 8/19/63-3742 ,P

. 'q&gx== n e w m .e m e 2~m w=>= w == m

~

1050 260

?00lrDRC Vit

. , . . . _ . . .~- . . . . -

-....n-

. -- --.n-~-

v. ~= w ;=o.

w 1962 pe=phlet seriel pile ' gm

[// M2 -2 N..

e$

M, . asede, n:rt * ~

s-3 _Cu the Effect of Size of Speci n=s on the Cube Co=cressive SW.h.

]-] of Con =re e. (I5 GIPv85, with Z.;gl.ish %)

()

r4 Ge:= cry. Deutscher Ausschuss f~=- Stahlbeten. Heft 144, pp.49-83' .. .

3 jj u

(1962). . ,

~a . ,a p,, . , ,,

.. . . . . r y .

q _

'The tests i=dicate that the appare.nt ec=pressive strc=gth of -cos-9 y crete does not decrease ith en i== =sse in size of spec *-= as i:

%j lo:s cs cu specimus cre eeually esd n=ifernly ce=ps:ted, c=d' es g' ic=g ca the be: ring blocks'of the testing m -' N are sufficiently *- ; 2

. stiff. Hr.reTar, if the eps

1= ens are cest e== rdir.g to DIN 1048 g

p the fir:t 4-e===t is not fulf471ed so th:t the cyplicatien of (4

the relcticcship betveen cube strength ez:d size of specian is' justified. I PD

w 4

w ys5,8 .

s-g y .

AM-h2-2 y

a . 4 g ~

ol2/6s

- - R a

w

. .n-r-. .

RQt &TE M M M .%~'M%N 2 W 5T$N D'?-5Y5 25W W S 0

\~.. gam.-,m-~.-.:::w.

-~ , =. .< a yg.gs. -.-y.- rra.=;.u-s.c, 4_m - m.=-;.p'i1@~.i%.:RS%Ve

. w-& n-

. : .w

" ~ - - esg *2 22.19.".L;

.n y Te

{9.:ff1957

.n g p; d 2. 2 Periodical l 69130$ C33 -

! g,; -

~ q ,

% Rar=z.n, A.3. et al. ' ..

f O$ Discussica of "The Tr. fit.ence of Size of Cencrete Test Cches on R E.~E Mean Strc . th z=d Sta=dc ti Deviation",'y c A.M. Sev' 'e. 'E m

9 Maga:ir.e of Co.x:rste Research 9 (25T 5?-55 O'>.r.1957).

71 b-s43  :-:

~

$sq of cube size en the uMr. Earnan ly furti.rr information en the effect a .d th . Aln cyd e. 4 escion test tesults. A brief cocWsen i

$ is given of lateratory data with field date. A table.gives results '

O.5 of nean deviation in kg/so..c=. for.three different sizes oft _.de !

'  ?

Q:.3

and =ortar pr.sms, the ,

'er of speci= ens bei=g 80 and 160. }

n% . e.*-

9 -

AM-h2-2 6

@ ?0?-9-1-1'

- 5x

• • • , *.,& a l * [. w e-

- *e .:.

p r.9

.: .i

+.

' . 'g. .

i ft h"5.K.T,.].' . . . .~ ; .~ . . ~. .a .

a= ~ ~ - U M Y ' d - * " ' - ~ ~ '"'

,3 - 1050 261

P00R ORIGNL

~.-_. -

m.- ..... - <. m ,. -- - .~ - ~ .-- ..-

__-? -.c mg-g_$ w.~

'0 q s

..e,.....x l  ::~,.~ c:,:

.;m

. s3>.

T@ w a 0 1 i e

a fTh - kn e-- -D I s.t t

a.-

.3 Neville, A. M. . - "

M The I=.fluanece of Size cf Generste Test Cubes on Mean Struneth ani.' >l Q btandard Def atton. - -

EJ

.;-- Magazine of Concrete has,earch 8 (23) 1Cl-110 (Aug.1956).' # J',' @ .

-a T

$s Su:= :ary: It is suggested that the mean s'iength and the att 'idard 47 ij deviation of a sa=ple of con = rete cubes are functions of the cube {

M sice.' The results of tests on ever 300 cabes of three sizes are s-

$ given, and from the statistical analysis of these results it is i 1.i cencluded that the sn: aller 2 78 in. cubes have a significantly f 5 higher mean strength and higher standard deviation than the larger g 34 5 in. and 6 in. cubes. From these results, it is atggested that t

'2 the stindard derhtien obtained fi::=2 stancard 2 78 i=, ucrtar '

cdes ej.ves an ex=essive esti= ate of the effect of the variation f.n cement quality as ec rpared with the results obtained fron 6 in.

[

[

2 or h in. cenerete cubes, e

W. 22 /1o/56 E P' FCP-9-1-1

~

AM-h2-2 > i EiR$m-4 91W a #..W.M G E W 9 FtM ?.J P_. 7f_O . 96 AL'cC2'.1M... aW '

if?MMEPK-W-*2:R9?WE">4x.23fd4p5EEW.hh?W1gEji '

P 1956 [

Peri ~u ~1 l NN

)q N M 4 V'*'l 62 5 c'50 l 7' -

N. .> Ne W 'e> A. M. 5 *

.Q The Use of h-In. Cen: rete Cc=pressics Test Cubes. 5<

53 Civil Eng neerirc. & rubhc Wor):s devise 51 @S) 1251-1252 -  %

3 (Nov. 1956). Abstract in Eng. T-v av, (1757). )

'J r 7 . 4 sa  :

2

) Series of r. . , a ative tests on cubes of varicus sizes; it is s..g-y gested that h-in. cubes be used as standard test cubes vbenever 5 h narinan aggregate size is net greatar than 3/4 in.; by coc aring 2.78-in. cubes cast as such, with 22/.-in. cubes obtained by ce .

?

d E 13 ting up 6-in. cubes, it is shcun that 3/4-in. aggregate can be 2 g

3 s .ccessfully used even v.*th this a7l sice cf cube. 2.-

.~{ . -1 re.: G

'3 J

!N h 3

=

4

~

p AM-h2-2 S 2/8/57 I i

%w.

. ;s . n

• .- +.2:.:57.:4-'-t.=.5 .d.=51%@5.'.:f.54?a'.**iM-c-@. -AM26.:-Wr;+:-MM.2i 1050 262

G

~

P00RORl31NM.

...e .-:

y,-c.

. . . . : , . , g - . 1. ...w -.: . .

$ 19$k  % icdical 691 305  :. .-n..-:.;-wx4'M D 23 g A g -m v n

~

K.

!$ Efsen, A. c=d f"--bo, O. *

?

g Cemssive St ength of Cc=: rete Cr'f **viars. (IN D*JESH, with no - 2

~i of 4 + sus:ary) . . g jgt Beton og Jernbeten 6 (3) 91-93 (April 195h). .

.4 .

~

~

bt .

n

] (1) The cassive strength of .c te cy'4~1a s was ds+M .

f Aj by.the fo22cwi. g :::sthods:

M (a) the cy'"~'m were capped with 2x:rta:r; ~ ~ }

f

v2 (b) a piece of soft va11 board was placed between Es cy? ' A- $

g and the testing M4- e. &

44 No diffme in strength v2s fou=d. A 5 d- to e-be strength was found to be on the

$ (2) Ths ratio er 'of7 cyi'  :[

average to 0.827. This ratio decreased with increasing Zs corerete stre=gth. (

AH-h2-2 a# (Abstract by J.M.) , 12-17-58 .

}Y aw ~

L

3. %m 3

, b,~,.t '

GRcTRssM%22E=.-2-MsMMcMek==7MemW5 &A N

!. R M W h 53nf M I.2 M ~R@;%~9- 35'@% W D'@ff- rD F M Y -Sh"k,.&q

. T h

3

5 19 o, }

fer d- al

.-u-iodical  !

656,905 150 'Q v j; A M-M *l l 691 M 63a '

D g? ,

$ Gc- --- .ani H. F. I j

a Sffect

c. of Size and Shn=e of Test Soecinen on Cs._.ussive Strerrth Ccacreze. -

1 Mjj f

8tructn.El lhterials Res, Lab., Lettis 7.nstitute, Chicago Dn'b tin --I g h,c. 16, 16pp. (1925), , eprinted in Soc. A=.

Sec. for Test. Iht.

3 _23,, (2) 237 (1925). -

o y Co==ressics d

tests were cade at 7 dayc to 1,,r on 1755 concrete e

5 S spee -'* s in a study of the ec:pressive strength of: (1) cy' d 4 3

• g ,1% to 10-in. in dian. and 2 dia=, in length with sice, grading  :

47 cf aC5:ecate, cix, consistency and age being the variables; (2) i M cy'dnders 12-in. in icngth and fren 3 to lo-in. in dian.; (3) cy-y; Me.s 6-in, in dia=. a=d 3 to 2h-in. Ic=g; (h) 6- znd 8-in. cubes'- :-

= (5) prisss, 6 by 12- and 3 by if.>-iu. #

y *:ce 6 by 12-in, e -lir, der preved to be a satisfseto:7 speci:ma. '

A u

tv.5 G5:e ates should be "ted to 2 in, c- lees in dia . fc m. -

4 (Abstr. by lE) AYM-2 5 12/25/56 Q-w.w->

s- . a ..m .... . w. .. . .=a , .:---= =s. ~ a - .m- -- - - --

~

1050 263

~

~

700ROR'lNil m

APPENDIX D

SUMMARY

" RATIO OF STRENGTH OF 2-in. CUBES TO 6x12-in. CYLINDERS" e

1050 264

constructico technology lobomtoric Ratio of Strencth of 2-in. Cubes to 6x12-in. Cvlinders Neville(1) has suggested that the ratio of strength of 6x12-in. cylinders to 6-in. cubes is about 0.83. This ratio being the average of the L/D correction f actors of 0.91 and 0.75 from ASTM C-42 and British Standard BS1881, respectively.

A f actor of 0.81 was determined from an analysis from 11 .

investigations.

L'Hermite has also suggested a value of 0.83 with a range of 0.'76 to 0.86 (see Neville Ref erence 13) .

Other research data (2) indicate ratios of strength of cylin-ders to 6-in. cubes in the range of 0.80 to 1.10. RILEM and CEB recommend 0.80 and this value is specified in British Standard 1881. This reference (2) also sites other references (Table 7) to indicate the strength of 2, 4, and 6-in. diameter cores (L/D of 1) is approximately equal to the strength of '

cubes (4 and 6 in.). Applying the L/D correction f actor of 0.91 the strength of cores is about 91% of the strength of cubes, or cubes 4 and 6 in. are about 10% stronger than cores.

In a later r ' ference (3) Neville has su=marized several inves-tigations which lead to the conclusion that the compressive strength of 2-in. cubes is a it 18% greater than the strength of 6x12-in. cylinders (see at ached Figures 8.19 and 8.21) .

Figure 8.19 shows that the streng th of 2-in. cubes is about 8%

greater than that of 6-in. cubes. Figure 8.21 shows that the stre.ng th of 6-in. cubes is about 10% greater than that of .

6x12-in. cylinders. Therefore, considering these two together, the strength of 2-in. cubes is about 18% greater than 6x12-in.

cylinders.

Gilkey (4) reported the ratio of strength of 6x12-in. cylinders to 2-in. cubes to be 0.88.

Other f actors should be considered in estimating the strength of 6x12-in. cylinders from the strength of cubes cut from the remnants: -

Reference 2 states that:

"A core may be inherently weaker than a cylinder because the surf ace of a core includes cut pieces of sggregate,

- ~ y of which will only be retained in the specimen by adhesion to the matrix. Such particles are likely to contribute little to the strength of the core."

Bloem (5) has shown that the operation of drilling can damage cores. The strength of cores was 7% lower than the strength of 1050 265

. 'cocitivetion technology laborotoder push-out cylinders. It seems reasonable that the same might be said of sawed cubes.

It is generally accepted that the diameter of a cylinder or side of a cube should be 3 to 4 times the maximum size aggre-gate. Test samples with a smaller ratio of minimum. dimensions to maximum size aggregate will produce lower compressive streng th s. The 2-in. cube with 3/4-in. aggregate did not meet this recommendation.

The ACI Building Code (5) provides that if the strength of cores f rom the structure equals 85% of control cylinders the concrete is acceptable. It wculd appear that a similar factor would be appropriate for the cubes cut from the body of the cylinders to allow for potential damage to the samples.

In summary, research data do not reveal a precise relationship between strength of 6x12-in. cylinders and 2-in. cubes, but indicate a range of values f rom about 0.92 to 0.67 with an average of 0.80. This f actor was used in our previous report dated April 19, 1978, and still seems appropriate.

J. J. Shideler, Director Administrative and Technical Services JJS/md CT-0539 February 27, 1979 -

1050 266

' conetsuction techno4ogg labototories References

1. Neville , A.M. , "A General Relation of Strength of Concrete Specimens of Diff erent Shapes and Sires," ACI Journal, October 1966, pp. 1095-1109.

2. Concrete Society Technical Report, " Concrete Core Tet:ing f or S trength," 1976,. p. 34.

3. Neville, A.M., " Properties of Concrete" (book) , pp. 430-492.

4. Gilkey, H.J., " Discussion of Modified Cube Test," Proc.

ASTM Vol. 34, Part II, 1934, p. 415.

5. Bloem, D.L., " Concrete Strength in Structure ," ACI Journal, March 1968, p.176.

6. " Building Code Requirements for Reinforced Concrete - ACI 318-77," American Concrete Institute.

1050 267

um # **

som, rem or . int mancan djQ,6.e. ' ". '.) ,

l 1

&,concu N ' n enniois ?' { '3f:.,o...i,.,a,4.(]{. ,

A- N 'll'I $* 'p.@'.,y-d. @,1 -

. i.ireDrotchle, J. F., ' General Ela.lle l y ,Flat J . $lahs Plates,;Act . Ip , L,end,2 l. i';:$/?.  %,(!.' ',1c,

[.,',j ,k g .

• ,. P. ,; .t.

pp.'Analysis 125-152. of L.4 )! Y Jou AL, l'ruceedirisis V. 60, flo. 2,. Aug.1959, 'l

. ' ' , ' ' 4. u

. j'. ."' ( i j.!j.nep'

%' ' ; 'q . i ' N .-

' ,.5

15. Drotchie, J. F., '* Direct Dislgn of Plate end She i Structurce,.T'roce'edings m. ' , ,! p; ;' i

~

a ASCE, V. D8, STO. Dec.1902, pp. 8Dl48.

16. Urotchic, J. F., ' Direct Design of Prestrchsed Concrete Flat. Plate Strue

't

• • 't]' ,

.. ^*- I'.

i. . iJ A Ge11eral Relati.0113' .for;.s' ... . trengths ,... .

O-S,e - .' .

tu..s, .,.n.

comi,ncoe,..i 3 i,i, yn g. v. n no. i, . e i og..,n. n.is.y.  ;.-

ed...

.of Concrete Sgec,inte.ns.o

. ,m . ,, ,..,....

ou.nu., i ., . as,.c, ,,.....,

s. .a. . . .,,,, ,, .s .. . n,...in ,,,,,n., ,.,. . ,.u n6.., . , .i <s..

,., o , .. . c .. . i.,,,,,,, ; . . . .

N e , ,. .M

.y.1. ,.',%. ,.

DIfferent

. ....,,,/,'. i n Shapes'andyi.zes d, J' 3 ,,,,..;

W -

.,.4,.

u ,-

. ,. ., ,, ....<. f.# .

e.p .avcitoo pie, s.nating .i ilm. . ,.  :-

.. , r., .

c, . .

s.. iiIli..,N.w. e ntett.r, i, or r,....i p rov.a cop;.. .

.I P..I 2 m.y be a.,ed .I . subsf. s ..tn

.. .-l : ; . '

.r def.lf 'P... -

By ADAM M.. NEV,ILLE -

2g

- ,-33. .

e.ai.in a...n. n vin..i. u,.oo .n.6,nti. h 1,,  : .

g p.f;.3 ,,p m 6.i. i... w. . .

bonaaI,;.i.nc.a,pt.,..:.od,ig.ab.r.eng.,ivi,(. , . . g. . i.,i, p,p .,. g..ns _ terg.,,, j ,,,,3..,

f

, , , . , ,;. ; g . ' .wir + . i.; we  ;.,.d. ?f . . .- :c> >'

., . , . g,. ,q.g m.,g,  ; . ,tA 4

... ~ . . .. . . .

m ,f. o .A , , .

, ,,,,,,,t, g  : , ..

.- v L, ) it is shown _that the ilten9,,,',d to one. another: by Im Io e:Pr'"I*" 3..^

.1 t. n c.r..a 6, A,,, it in.irio.r. A. . so. ivas, r.iiW n. 43 si .f. .,p  : ~l S .W,..c.',.a,.r;l.g.f i  :.N 9 an d ' ri t; .e iri.

o,.,i cono i.,i,a.g.

, .gign,.,,p.g,io

• q . -

g, oce.,je.,i, , gs.. e gegrichief...Jouer:Au

,,g., )- p.

p , [,' 4, >eness tnodulus of aggregal

, ng i it results are pegn ed Jho sec g,,,,,f,ri,tmi) can be re .lailan ti discuit. * -

f L

i

.N

• g

.,4 4, . , A i<.. c- uc. inntioi.. ,.o. su oss, n.Jr a <,.o . .,d-[, il.) nu / 1 .'Q.rj- : C'"*'

,.g niarip' compeesiive ifrea9'bl' t '

-(

.W. r

'.:,r ,

i .. J , H. W ,. M.y t,cy. ':. } 7j.f.$p',p,,e ..f, .l . g., in Key words: compress

'i ' f.i j 7 q: 3.( r l 4  !,1 'J'.llent cubes:' cylinders; fineness mod

~

i i'.l 3

.'jpDiscussion of this papiir should resc i ACI heaY.Dh..l.*) 67,j or f

s 3

.i.'..-

It Tuz been ro coMrAne on cony n publicatfort g gti ,grength'of ti thedlIICIc"I'I Pait 2]kitart g gl Y P"' ?c j -

nr I le o

! P ' '

l'l f:8:'jf!'SIriDp5I$IIldiunit

1. s

'hclp,ht'lo diomelet ratio may:n) r * , i '. '. u. ~. sant '1enbkluhgY N gtg 6..,

Q h. 6nse ilandarg

'.yp@M' Of ..3 M i hdM . s m .,C

?

.<a ,j,v,tgij -

l.$ gudalent) cubes makes conve,rs.os, , .

d C42'6Lon;.Drillsh!

l, .h!ih.

T .dt !. . f i .

P

.pl,0 ' t J, ..)

'lodos 'de) disenh[0"5I d8,g iMslon factors are availablede.g.ly

, bg; g ig .',eQr'nii

.g""Mrtl B.S.'lagt:1952. The probletn.h . )cp ,y . .. f,tl d 56 'desettben : pt no 'desarr adobreelentl4delite a '% (

g lA'-

statiis de concreto reforzad6 y pHif6rz r d y de prelE tan 4tllod6061inbilfleddos  !, I sj iy[.workers..ii , .nt. .dnbiY ,donnertn'oh,8hMIN.N gg T5 7.hhng:utid '! i[js intil determinor la'entsia de 6gelht&ih nlo /la hhtsh%'v616 slid &'d&*lpidedi'presi orzadas optimlindas.: Los metodos tb'opuestos d)ohip slillentbar i~gl. P'YKilciyn' kl,4, s

,{ ,

bht a genero g,g3 ,j 7,. , .,e ,y j , ., ,p,i. q ,

. ,,' ' ' .1 : ,. '. ,!,'

, ..,9g , , .I 6 r DC 8I tr - - r il '

if ' ', .

l}ne..Techniqu6. Itallonnel,1,6, pout.:le DImensionricm,b, cIft,.i' hip.I6 .j .h.

h, llouteur dectil des methodes d$ tilminstonnement opilm81 i comlnertt d ', dbela/b .- GENER 8 rpples pottr les plargues tiii.b$ lod at:n8 ill'n b8 ton ptlcontrninl l preeddlijt!b)[ 1

" I '- ^

d..? ff. ' -(Irat nl tempt of Ilnd.bild.nn ,ovet$,pi d , t6ss', t l' tlon e' . ret.kTIOtbsNd n ,h/ '

nothodes simp!! files pour,la determinallos de In chargo do fissu llon et  ;) ul-U[ n concrtld spec men,i, And' 118 . m, l 'shnti']'h hnrge ultime pour les plaques prleontra nics optimislek.. Leifin (lindch,de lii.c{  :\.,g i i Hlh0,.8IIC8IE{]I -

r ble:!de.thC .jsm6

.osecs sont cornpardeslavec'.d'autres,}tecimiques. ,e hiensformern nt; y f .

. isttggested.thnt 6treng i gs Me,l.6nMthrh' n..ln. h/d. Ils I,1cIN.Ih o

[i i

.. . .. .it! ! ,! , ,.

rn ne lott rat o I 1 e a

" WirkIIchkcIlinahe'.Methinfen lum Enlivujl,7 von iPlatten,J. ( rf, $ ., i I t'd Das Printlp von. In' jllii:crer NI ntw!ckcIle pg..lfd8

.I; , f.),ofbud another. The Inst of th 58ll'iddenIrutnI jl , afIous statidards. The influctighty, , .pr ntwurf von bewehrtid und Vorgespannten; pihllen"tvhd ben,f:Udd belehrle,oplInthl'eb g.7

. . . wherd.P is strength.bf iljd BP,h ,4,.-

n( lderallo.flo!

ercinfachende Melfioilen zur IIc.ttimhilldg von Illss. dild Drtschinst von optird&l,, f I k 1;I ,l..h(!,G.

prohngY o[

occierretifdh,cf 8b MIN,I' . 2 %vehkestillrik

,nepi embssenen vorgespnamten . l'lhiten ) w6rden .'aufgezelgt.ti DieivorgesclilegeheriM - . I, QI qg) [] oll'g - (os g(lugnc('d lethode~n werilen'mit 6nderenEntwur iverfahr{n.vergilcl,i,ene f ,,g ,

o,f,y,n,C g lven . level,of str6: .,

- . . . m u. . .. . .. .

ornram an^non "'" sin"unns or s'im"^ "

Act n mb., M..n m. H.,ni. i. ,i.. .: it

r. corer af rnota...ino, uoe....i,y .f Anm.t., ns C... .. f.. tw. ts. win

3. .h tc lie w.r .. fo..neilr prof..sor of coner.t. tect.nology .I th. Univ.rstry of 8

sh eeInthis other. threetype of specimen cases,131anlis and folcII0marp,'wns usedllummel by n$etore'inve al.,

Ino I.. w. f.eller li, h.J

.r,ponneeJ ..tv.J

.fe.n of .n on flie Univ.r:Ur of M. nth. ster (InOf .ntf) I.tuffy. In U.S. Hurents of Ileclamntlon Is iio reauIts for 0.In. ctibes were nynlinh,.

4,60 me....ii. A...a 9:ne ino .e is.. ne a cones. . .. .norooy. : .

.,r.

,,,es,.J et.

19d1 Med.! of it.. Reinforced Conce.t. A..oct.ilon (Enit.. in iiivison of serocive.1 ragen.... In these cases (togt.nis), the the strength of a G-In. cube wn., nssumeil to im 1/0113 tomfon .....,ch .r o,.. . nse crnot n. .i.e .. .gt ndL .nd recenti/ th Univ.estfr of of c.t a .....a .., .f o,.a,,.i. sevate. . unive,.iev.. a .-

the .strengtll of a G x 12-ln. cyhk 'mo eylisulcr-cuin rallis sif 6, .

.<r. A f,.querit JOURNAL tonihtot, b.1. tverenily (b.1,m.o el ACf Commiff., *' 207 .,',' ;is n;: average of the vahics presettbed by ASTM Standard C42:Gi (0.0--

C,.ep .nd sVolven.

u. t..' Cis.nge. In Conce.les . vnember of Commili. 115. R..e.rth, & n emiser of * '

co nnie.

,,,. s, .,,s.,d. co ,n ..is .. . of a..ute. of sie.nger. ten. of, cona.e.g .ad e .en.mber holj l.nnd hf

',- Drjtlsh u,tandard igg,g.1001,:lD52 .(0.7,5)liTheisnmc. r.esu.lti g

c,., .obtalned

,, itc'n llPermite'a

• formulat-ll Nf , h %, gW,#IhA9 .

['=,ca+c.uy,39.h..,,,p.,a

' :, ' leads &. l to.' tiFc.

observed strength since a greater volume of the specimen . ..j , t '. i more uniform of premature failure. stress distribution, and therefore a lesser likellhood f a

b,

• i for P. = G350 psi, where.

,F . Y,n N,j j, r; l ioe7.fisg) '

3 i

..g Syji i

c.t N.! ,,,.' !?y.l.MY)(a[e.'

's '

. l. '

We can thus postulate: .'  : . Po e strength of cylinder, psi, and T;$ ' * , ,i;%. 98 W, ,]; ?; r. a '.*h.[. .',.[9 9 i"; , * '#

/ y )  ; h.' .P. = strength or cube or same lateral dirne'istori. I',81[.'?. v- .

' .E..'7 ,:

.I' P=Fj

-h k*,'(* 'hI.I,-)hk It should be noted that thcI relatibn developid. Inter [Eq. (3)] fi

,/L, dS l/ * 't'q bl hi -

.\d . ,:i the data of all the cleven Investigators.llsted above yle,lds a value

'p,.'(,].t?,. g @, S* -

' I. : P./P. = 0.DI.

c7More specifically: .

it t 2:! .

. ).c. '/ - N v"!i@WI M b " i" l'.' " '. ' '

w ,

. .- Q.:gh- p g.T. . iis.Nii .

.., i',,'y @4

.. 'A, general}orm

,;Y of Eq. (2) casi therefore be written in nondimension l .a.. .p . ...,3..a.gg, rp i v. p O ,

, gy 3

, . !(. ,. ., p. c. -

. - form,. .,.f...,.,.

. . .... t . , ..,,, ,p,p; .; 7t Q. c.'- - if.,';

} P=rj h 1 1: E -KEY ;TO. SOtJRCES C

.,,,.'1 ,. . 0 . : r. . H,,,c. W f.

q ,j g

1

( g- X d,j

. . g. . ..

P_,

, P, m p V__ fL d V. , _he , de (2a) iljj,. i DATATABLE FOR.3FlGl. "I lp 2, 3, ANDU f i jf p ' ;. .% m, _ n. e ,f m .3 .m,. .:-

QF .

g .

4, %

c,

,; , ,i/...* [ ! M h ,1 v. 1 where the subscript 0 refers a ., to, "q:.9. .,,,,a . . ... : ner.,en,

y. , ,.1,,..,y,.io,

. . f. ,.g . r 8 9.g .n

.- . i . I, - .f' 0-In.- cube. . ,

y -c g db 1.l. ;)

• ""? '. '"* ' ,., F.,',, A

• T: g i.-['j.,i.y g :..

,g,e 1 b. h.

tit "

• IM IL has .been found cmplrica119 f i

[l. Ne.tu.,h. !ab *

.q. .

w.,g'. ,. .,; T. I

,LI that P/P..aand hy' perbolle relation exists It is reallred that the sIrength of a concrete' specimen may,'.als~o. i

'1

.f. tween a dimensionicsM:y .

,  : i,.

l.i cba. .. 'l i be influenced by other factors, such as the modulus .

L5S

,. I of clasticity of the?.j!";3 N.

m' ;. Q )..th' u kac4n.wi.v.pfd

.f, A r, h

- ?p .

oggregate, its Poisson's ratlo, the aggregnte-ccment ratio but .

iiq ;h.,:l,'4.f Q::'(i,i

','j q; 't . ,4 j [ h , l'.,l;Q'Q);/,l;@;p., ,

.1 3. '

' beexperimental ignored in the present data approximate on these nnalysis. factors .

th n '..

are perfora.

. :'. M.-s; 1 nyallable 39 ;' tjj

. . . .,..,; !p.ey -g ;wlli,stnce

+ h.

4(Jp W hi;,,,m. .na Q l.$

' , ' ! 3O.dh. f. .+'-

f i.L. .T. . { . . 9. . . s , -

Test results on cylinders with h/d ratio of 1 and 2, prisms w thi h d. d. * . yi' 4: ; <s P -d. i."le$'lI'"Ul"

' ' oierir. . . n %. <

f. . 's-

i.8;.

ratio of 2 and 3, and cubca of 11 investigntors, hol ,/ - some

. .I Since ofinwhom a 0-in, cube have,h. = d.', h/d. abdM': r,q. . .

N N I N .'gh, r .'

been concerned with the problem in hand but provided ultable dt ta,y { f ..g D O'. Ara'ack ' i .h p' $ '..

.g,,

1 p,term p j..reduces'i.

. / <. V./h.d. = 0 in., the ko' were available to establish the form of Eq. (1). These href Connermrn','lW.h

. . sg)i;%

(1923);Nevillc Ulnnks and McNamara' .(1935); Gycngo[(193s);'iCor'nirikt1,N, : 8 .

' i ' g r + i, y .a y [ * ;h;.Hni d ' . Q'. , s (1950); 2 diczyqskl!.8 g

yp

,p.,

'[,j ;h' ' $y!-G. f[S.I'" , O @q.fy .'.I',fr, ~. ,r,ih (1000); Ilummel,(1050); Wesche, nud Akroyd' Drand58 (1057); (IDQ;'KankamHl IIntman']ID57)h(IDG2)! -;' W A id {;p i.in inchea.'. '.

S }' 'gdlmensions '

U.S. Durenu of Reclamntion'8 s

-l J - ,

U U,N" *I- I' - 'N 0 !iN

1' Ti' relation between this qtianDM d TY (1903). The data refer to many'differenty'.{,

Y .f.y: P/P Is shown in Fig.11 p.'.'.; D ' M'E'70i."E ,'*k

.concrcles, cared in various ways and tested at'd numbi'r;of riges..p .s'V To mnke comparnb!c the results of these different.investigallons on p .. - and FI 6 2 shows the t ectifled plot kI.U/ , d 4 .it,Y[)

a wido vnriety of concretes, it is desirnble to referiOio' strength of k,,).'

_ . g , plpg, y,j [dn'i.. i g'}.]l 61. d' i

'. ' . "I ' [,. .

'g , ' 'E,, ' ,[fj f]p..[.h.h .I"' : ,N,y,p:(,#bN specituen of any diniensions to lhd strength,of n "standnrdspechncul .' f.' .* . ', 'l In the present caso..i.i.- . n 0-in, cube , . t.

made t, 8

of tho snihn cont/.'1')#*h,"aus reto.ives chosen'{a,.?l,'[ .

' W, ,, ', } eg' ,k,,',z;,{J y

J',p,gr,g'jgjg,, f,i,, f,. ,;j,

{ g ij".3 , . ,

I

.  ; J. -l, j ' ,,.. ,.{W, . 14 - . . ; i .. , , , g .{,,] ..'

_ . / c'f f o.U'l l J i;;~.

,.:- : Concrete Soc.iety _ec7nica leaort No."  !

a

>1 4

.. I 2

F RESEARCH 1.lBRARY g poRTt.AND CEMENT y Assoc,AitON g 1050 270 se7

( 6 w -  % -

a ef exnm4 o w c a o x w 0- M K i-- ,.

(S] k9 k 9, ( I --

1. = "=- 2C' m

' W Q W~ % ._Gwsgin r;c w Ja A. - m d h?

~._,

.3, wist e-w cr --

4 g

'mL --w-m w A\ W_ ~

^

t . ; -L

= -

- . ---4

' 3 -MM '

- ~

6l_ __ _ 3 m~~'

m - =1- _w;--

w m R;m a r*= f _ - _ m -

e 3-1- vm ,

=wm

• .= - & ,= '

': A g

_ ^ 31}_-rgy _ - _ _ - - - -

~__ -

w -- - __

( i tee 8"" "

p N.

w=

[q hhhY,& m'

.- - x= -_ _ - - -

_=,n y- Jc-m - - - - ~

~

,. M T e , _,^,, _

'iYNil$ **

.,w g .

R QM_ t..Rg *1=* ~A-__

-= ' - 3- -_'~ -

^ ^ ^ '

}"_ _, a , n _ __ _ +

~~

= T5 '

^

ga; .m f j z = ,- 7- - M g-y - p :x _

~

f t -_ _a .

E- -

_xn .

_n, y1, -- '=

n_ c.- +

sy.

.g

-r;gya -

_4__u 4 >g.e <M v.c.!~w -

3

, y,qn- ,.

--_ ~.. y

. . W ,=- v "

u~ ~"

kU:b n .= $$hEbN- M - Nb -

. Pait 5. Evidence from research and practice b Introduction Table 3 Relative strength of cores of different diameters.

The procedures for estimating Actual and Potential Strength recommended in Part 3 are based upon informa- Reference Number of strength of tco mrneia. cores tion gained from cractice and research. The object of this cc'es strengtn c 150 mm c a. cw Part is te summari:e the available knowledge, so enabling 6 50 0-98 the validitv and limitations of the recommendations to be 9 716 1-04 assessed and indicating aspects of the subject which 28 48 0 80*

wculd merit further investigation. 31 - 1 00 36 128 1 05 Relationship between Core Strength and Actual *Several investigat:rs have commented upon this result but thee Strength seems to be no explanadon fer its contrasung with cther eviden: .

The main factors which need to be considered when relating the Core Strength'to the Actual S:rength are: pressive strength of concrete with aggregate of 30 mm

(*) diameter of core: maximum size is permitted by the relevant Swiss stan-(2) length / diameter ratio of core: dardius, (3) direction of drilling:

• Apart from tests on cores having a diameter less than (4) shape of specimen; three times the maximum aggregate size.the effect of size (5) method of capping; upon the compressive si ength of different types of speci-(6) effe:.:c drilling operation: men, including cores, cylinders and cubes. has been (7) reinforcement: studied by many investigators's.sa.a.u.3". It is genera:Iy (3) curing of core: accepted that the strength tends to inciease with decreas-(9) moisture condition of core: ,, ,g ing size of specimen.there beir'q severalinfluer.cing facters -

which are discussed by various authors"" 8 3'"u. Any (10) flaws in core.

94h difference between the compressive strengths of 100 mm Diarnerer of core and 150 mm cubes is, however, so small that both Er;tish Standard 18PXeu states that cores shall have a RlLEM"28 and CEB"" suggest thatit is of no significance.

diameter of -ther 100 or 150.mjm. This standard does not Results of substantial programmes of tests on cores of relate the permissible ciamet'er of the core to the maximum 100 and 150 mm diameter. given in Tab'e 3. indicate that.

aggregate size, but standards'2"' of other countries state genera'iy. the ciameter has little, if any. effect upon *he ~

that the ciameter of the core should be at least three times meast,.sd strength.

the nominal maximum si:e of the aggregate.

Several investigators u d" have examine'd the results of Lengr/r/c'lameter ratio of cores ,

driiling cores with a diameter of less than three times the The measured strength of a core decreases as the ratio of nominal maximum size of the aggregate. For example. its length to its diameter. A. increases. This report recon-ccres having a diameter of 50 mm have been taken from mends that.when capped ready for test. a core should have concreta made with aggregate of 20 mm maximum size'". a length / diameter ratio of between 1-0 and 12. It is.

Fct a given height / diameter ratio little, if any. difference therefeie, convenient to correct the measured strength of was noted between the mean strengths yielded by cores of any core to obtain the strength which would have been 50 and 100 mm diameters but the smaller cores tended to obtained had the core a length / diameter ratio of 1 0.

crcduce more variable results. Similar results were ob- The effect of the length / diameter ratio upon the streng h tained durHg an investigation on the strengths of cores of of a cast cylinder or a core has been studied by many 50.100 and 150 mm diameter drilled from concrete with a investigators'u.a. o.n.: .u.n.3s a **""; the results of tne maximum aggre gate size of 30 mm'", In this case, it was tests are summarized in Table 4. all the data being based, snewn inat tne testing error associated with 50 mm diam- upon a specimen having a length / diameter ratic of 1-0.

eter cores was about twice that associated with 150 mm it is evident that there is a considerable range in the find-ccres, niis imo!ies that. to obtain a similar degree of ings:it seems e! ear. however. that the refationshio givenin accurac/ more cores should be drilled if these arc of small BS 18818" underestimates the cifference in measu ec ciar eter. strength associated with a change in length /ciar eter rado.

Evidence is also available on the strengths of cores A detailed s*udy of the results obtained in e varicar having a diameter ecual to the maximum size of aggre- investigations suggests that the strength.i f. cf 3 ccre gate in the concrete. Ceres of 150. 200 and 250 mm having a length / diameter ratio of 1. can be estimated frcm ciameters were cut frem concrete with aggregate of 100 the strength. /,.3 cf a core having a length / diameter ratic cf mm r aximum size; all yielded similar mean strengths""- A. by the formula:

The testing error again increased as the diameter of the ccres ".as reduced. .,

/s = 3 52 54g 1050 271 Arciner investigation"" inwivet, the testing of cores cf 35. 50. 75 and 100 mm diameter with mixes having it follows from this formula that the strengt

• f. cf a ccre rnatmum a;;regate sizes of 4,8 and 16 mm. It was found having a length / diameter ratio cf 2. is yie; cec by tne

Part 5. Evidence from research and practice 0-4 Introduction Table 3 Relative strengt5 of cores of different diameters.

The procedures for estimating Actual and Potential Strengtn recommended in Part 3 are based upon informa. Reference Number of Strength of 100 mm cia. cores tion gained from practice and research. The object of this C 'es strengtn of 150 mm cia. co es Part is t: summarize the available knowledge, so enabling 6 50 0 98 the validity and limitations of the recommendations to be 9 716 1 04 assessed and indicating aspects of the subject which 28 48 o 80*

wcu!d rnerit further investigation. 31 -

1 oo 36 128 1 05 Relationship betvveen Core Strength and Actual

.Severat investigators have ecmmented unen this result but there Strength seems to be no explanation for its cutrasting with etner evidence.

The main factors which need to be considered when relating the Core Strength to the Actual Strength are: pressive strength of concrete with aggregate of 30 mm (1) diameterof core; maximum size is permitted by the relevant Swiss stan-(2) length /diameterratio of core: dard'u'.

(3) direction of drilling:

• Apart from tests on cores having a diameter less than (4) shape of specimen: three times the maximum agg egate size. the effect of size (5) method of capping: upon the compressive strength of different types of speci-(6) effect of drilling operation: men, including cores cylinders and cubes. has been (7) reinforcement: studied by many investigators's.s.e.n.uas'. It is generally (S) curing of core: -

accepted that the strength tends to increase with decreas-(9) moisture condition of core: ,, ,g ing size of specimen.there being severalinfluencing factors -

(10) flaws in core.

94h which are discussed by various autherses .u :s.n..u. Any difference between the compressive strengths of 100 mm Diameter of core and 150 mm cubes is, however, so small that both British Standard 1881'" states that cores shall have a RlLEM"n and CEB"" suggest that it is of no significance.

diameter of e-ther 100 or 150_ m.rt.This standard does not Results of substantial programmes of tests on cores of relate the permissible ciameter of the core to the maximum 100 and 150 mm diameter. given in Table 3. indicate that.

aggregate size but standards"*8 of other countries state generally, the diamuter has little. if any, effect upon the that the diameter of the core should be at least three times measured strength.

~

the nominal maximum size of the aggregate.

Several investigatcrs" "' have examine ~d the results of /.eagth/d/ameter ratio of cores drdling cores with a diameter of less than three times the -

The measured strencth of a core decrasses as the ratio of nominal maximum size of the aggregate. For example. its length to its diarreter 1. increases. This report recem-ceres having a diameter of 50 mm have been taken from mends that, when capped ready for test, a core should have concrete made with aggregate of 20 mm maximum size'". a length / diameter ratio of between 10 and 1-2. It is.

For a given height / diameter ratio little. if any difference therefore, convenient to correct the measured strength of was noted between the mean strengths yielded by cores of any core to obtain the strength which would have been 50 and 100 mm diameters but the smaller cores tended to obtained had the core a length / diameter ratio of 10.

precuce more variable results. Simitar results were ob-The effect of the length / diameter ratio upon the strength tained during an investigation on the strengths of cores of of a cast cylinder or a core has been stucied by many 50.100 and 150 mm diameter dnlied from concrete with a investigators <u.a.:o.n.:s.n.u.u .o.....n: the results of the maximum aggregate size of 30 mm'", in this case, it was tests are summarized in Table 4. all the data being based sn:wn Inat tne testing error associated with 50 mm diam- uoon a specimen having a length / diameter ratic of 10.

eter cores was about twice that associated with 150 mm it is evident that there is a considerable range in the find-ccres. This implies that. to obtain a similar degree of ings:it seems ciear, however, that the relationship given in ac:uracy more cores should be dri!!ed if these are of sma!!

BS 1881'" underestimates the difference in r easured cia r-e ter, strength associated with a change in lergth/ diameter ratio.

Eucence is also available on the strengths of cores A detailed study cf the results obtained in the various havmg a diameter et;ual to the maximum si:e of aggre- investigations suggests that the strength. i /. cf a core gate m the concrete. Cores of 150, 200 and 250 mm having a length / diameter ratio of 1. can be estimated from c.ameters were cut from concrete with aggregate of 150 the strength. / s. cf a core having a length / diameter ratio of mm maximum size; a!! yielded similar mean strengths'"' l. by the formula:

Tre testing error again increased as the diameter cf the 2 5/x cc es was reduced.

t, ct er investigation"" involved the testing of cores b " 1 5 + 1/x 1050 272 c' 35. 50. 75 and 100 mm diameter with mixes having 11 follows from this formula that the strengts f: of a core max ;gn aggre;ste si:es,of 4,8,and 16 mm. It was found, , having a length / diameter ratio of 2. is yie;ced by the

sone a, nere av e a u envi e we s.w. w. w m oin s ....v.o....a. .- --

"teladve strength CyGnders . Cores 5 1 53 1 52 1 33 1 30 1 52 - 1 39 .- 1 37 - - j 3 1 00 1 00 1 00 1-00 1 00 1 00 1 00 1 00 1 00 1 00 1-00 '

5 0 88 0 88 0 69 0-90 - 0 87 0-83 0 82 0 88 0 84 0 95 3 0-85 0 86 083 0 87 0-86 0 84 0 84 0 75 0-81 0 82 0-92 i

3 - - 0-81 0 78 - 0-84 - - - - 0 80 -

derence 44 13 20 46 47 29 46 48 36 38 BS188i irection of dri//ing recommendations made by RILEM"U and CEB"U and is ny heterogeneity in the concrete which is related to the specified in BS 1881 for converting a corrected cylinder  !

'rection of casting may have a different effect upon the strength, obtained from a core test. to the equivalent cube ,

.rength of the core, depending upon the direction of sfril- strength.

i g. Evidence regarding the effect is conflicting. The tsults of an investigation""8 on cores drilled from Method of espping clumns indicated that the strength was about 12% less if Before being tested in accordance with BS 1881,the two  :

1e cores were tested at right-angles to the direction of ends of a core must be capped with a high-r. lumina-cement lacing. More extensive tests by the sanse authorm8 indi- mortar, a sulphur-sand mixture or by other suitable means. '

ated a difference of only 3%. which is not statistically The thickness and composition of the caps have some ,

.gnificant. influence 1upon the strength of a core, as evidenced by -

Johnson"H found that cylinders cast with their axes several authors'u.umm.o.n.a** but the effect is generally  :

orizontal had a compressive strength about 5% less than of no practical significanec. provided that the capping 1at of cylinders cast in the normal manner: Bloemuu material is not inherently weaker than the concrete and  ;

aund the difference to average 15%. Other results'um.s" that the caps are sound and flat and perpendicular to the 1dicate that the compressive strength of cubes tested in axis of the core, within the tolerances quoted in BS 1881. .l 1e direction of casting may be similar to that of cubes This conclusion is in agreement with the finding"*.an that  :

1sted at right-angles to the direction of casting or up to the same compressive strength is yielded by cylinders I 0% higher. -

. capped with neat cement or a rnixture of sulphur and fire l Recognizing the discrepancies between results reported clay as is obtained from cylinders having ground end faces.

y the varicus investigators. Johnstenm8 cast prisms from it has been reported *8. however that filled polyester ,

range of 23 mixes.The findings from this carefully con- resins are not suitable for capping, as they reduce the

• olled programme indicated that the strength of, prisms strength by up to 20%. It has also been foundm8 that the

.as 8% higher if these were tested in the same orientation use of filled polyester resins increases the variation in ,

s cast.The magnitude of this difference was similar for all measured strengths.

.ormal-weight structural concrete.

This finding was in accord with results obtained by the E//ect of dri//ing operation j lureau of rieclamation**8 from a total of 237 cores it has been suggested that the coeration of drilling can frilled vertically and horizontally from two dams. These damage a core and hence reduce its compressive strength.

wo investigations indicated that, on average, vertically Such camage is sometimes apparent when dnlling im-irilled cores were stronger than horizontally drilled cores mature or inherently vseak concrete. but normally it is not

y 7 and 9% respectively. possible to see any deleterious effects on the cut surface of a core.

shape of specimen A core may be inherentlyweakerthan a cylinder because - -

Jcst of the available information relating the strer:gths of the surface of a core includes cut eieces of aggrecate.

ylindrical and cubical test specimens is based upon tests many of which will only be retained in the s::ecimen by [

2n cast specimens rather than samples cut from a larger adhesion to the matrix. Such particles are likely to contri- j

enerete mass. The measurements are usually made on bute little to the strength of the core. 8 itandard test cubes and cylinders and so any observed in the course of two investigations. sleeved cylinders r<)

elationship includes the orientation effect. have been cast within concrete slabs. Campbell anc E The consicerable volume of informatieno.u.a.n.34ss.u. Tobinc" cast 150 mm diameter metal sleeves in each of W 8=n8 incicates that the relationship between cylinder and four 300 mm thick slabs. At ages of 28. 56 and 91 days.

the strengths of pairs of these cylinders were compared o

ube strengths is nct unique but depends upon factors such gf3 is tne cencrete mix and the precise methods of test. A sum- with the strengths of pairs of cores of the same size and O

-.ary pa::er produced by RILEM"" shows that the ratio shape. On average. the cylinders had a strengt.- 5% ~

etween the strengths of cubes and of cylinders with a greater than the strength of the cores.

eng n/ cia eter ratio cf 2 has been found to vary from 0 9 Similar tests are described by Bloem*8. Pairs of slabs and 15. A study of the information suggests that it is were cast from each of three concrete mixes. one tem;

ifficult to be more precise than to assume that the well cured and one poorly cured. Each slab was previced

-metn cf a cubeis 125 times that.cf a cy!incer havin: a with 36 plastics inserts to enable cylinders to be abstracted ,

PAFARMAL

• of 3'5 corresponding cores taken from each stab. The cor-time of drilling and any difference in the subsequent hydra-

' relatha between the strengths of the push-out cylinders 3 tion of the specimen and the parent concrete is likely to be and tne cor es was good ano incica ted that the comoressive ,

smail: in any case. it will be very difficult to ma ke a realistic s:rengtn of the cylincers was 7% greater than the strength a!!cwance for the effect any difference may have upon the 11 me corresponoing cores. .

relative strengths of the core end of the concrete it repre-sents.

Reinforcement The etf act of reinforcing bars upon the strength of cylinders Moisture condition of core  ;

has been studied in the United States"". A total of 66 The measured strength of a core is dependent upon its cylinders was cast. some unreinforced. some with one bar moisture condition'"'. BS 1881 requires that a core shall perpencicular to the axis and others with two mutually be immersed for a period of at least 48 h prior to test and perpendicular bars, both perpendicular to the axis. The that it shall still be wet when tested; this requirement is particular location of the bars was found to have little similar to that which applies to compressive tests on other effect upon the strength of the cylinders. The average concrete pecimens including cubes. In principle. the effect reductions in strength are given in Table 5. l-Similar tests"' 7"have been cenducted on 170 cylinders, of the meisture content atthe time of test is not considered l' to be a charar:teristic of the concrete affecting its inherent -

200 mm long x 150 mm diameter. some of which contained strength but iv be a parameter associated with the testing single bars of 10 or 20 mm diameter, set at various depths technique. Thus, it is akin to the rate of Icading which and distances from the axis.The cylinders were tested after similarly affects the measured strength and is, therefore, being stored for 26 days in air followed by 2 days in water.

also standardized. Provided a core is tested wet, tlierefore.

The average percentage reductions in strength are given it is not necessary to allow for the difference in moisture in Tabte 6.

content when inferring the strength of the parent concrete.

A series of tests conducted in Germany"88 involved the Some authorities"AH H "' do not share this opinion testing of more than 300 cores.151 mm high and 99 mm and advocate that the ccre at the time of test should be in diameter. cut in a vertical direction frem stabs. Variables dry or have a moisture condition similar to that of the included the percentage reinforcement, the number of  !

parent concrete in the structure. Account must be taken of bars. the positions of the bars and the strength of the l the moisture condition at the time cf test when reviewing concrete. The results indicated that as much as 3 4% by results quoted by various investigators.

vclume of reinforcement (two 18 mm bars) had little effect '

upon the measured strength, the maximum reduction Flaws in core being 31 .

There are many faults which can occur in a core: these include cracks due to a variety of causes. voids due to I Table 5 Average reduction in strength due to presence water gain beneath horizontal reinforcement and veids I of one or two bars."" left upon removal of an immersion vibrator from a mix of I

0;ameter of bar low workability. The information gained upon examining '-

Number of bar's Reduction in stren,;th (mm) (%) such a Core can be of considerable value. but the measured strength of the core is likely to be low and notindicative of y 1 8 the Actual Strength of the concrete.

2 11 1 9 Estimation of Actual Strength 25 '

2 13 The definition of the Actual Strength of the concrete within an element must be related to a specific test method. It would be possible to base the strength upon tests on a core  :

Table 6 Average reduction in strength due to presence a g en lengWamem ras or on a sawn cuce, of bars at different positions."' '" e res n de latw type of spechen wd {

not, however, be directly comparable with strengins mea-Diameter . Distance Reductica in svengtn (%) at v bar from axis cistance from top of cylineer of sured on cast cubes. Differences between Actual and Potential Strength would reflect both real differences ce-

< m) (mm) 50 mm 150 mm 250 mm tween the two materials and effects of the different s:eci-0 mens.The latter effect can only be eliminated by exp ess-g 15 26 38 50 33 ing the Actual Strength in terms of tests on cast cuces.

16 4 although these are hypothetical test specimens in 19at t ey g 20 0 35 11 4 01 cannot be produced from the concrete in the element.

50 10 4 86 5-4 The Actual Strength can be assessed from tr'e Ccre CD Strength by considering the six specimens llustratec in tD Figure 5.These are: C3 Curing of core 1(a) core drilled horicon: ally *. length / diameter = 1 "

Cnce a core has been cut. the method of curing. and 1(b) core cri!!ed vertacally. tength/ diameter = i '

t'ence the rcie of strength development, will differ from 1(c) core dn!!ed vertically. length / diameter = 2 Inat of the parent concrete. The difference in strength at i 2(a) cy!inderwithioplayerremoved. length /diamete* = 2 rne t:me cf test will depend upon the maturity.cf the con- - 2(b) cylinder as ext !anath w-a [

(g f/////' / 4(a/ ro etc/ ine strengtn ofIne satter is lower cecause et j

' {M-g/,. / ' - / "

the presence of the weaker material near the top. There is <

IUUn little direct evidence on the magnitude of this decrease but -

a general examination of the reduction in strength towards

_ . . , _m b"N "$ , , the top of a !aycr of concrete, the strengths of cores dri!!ad ,

a w*

• from cubes and the relationship between actual and a m

m N potential strength suggests that a value of 15% will yield ,

results consistent with the available evidence. On this basis. It can be estimated that <

' . 1 l - -

1 $

l l l I g the strength of 2(b) = the strength of 2(a) x j

~ '

4 20 [

c== :c m s:c.m.

" 1 5 + 1/A .{

Fi re 5 Types of ecimen used in relating Core Strength and 2(b) to J(a) There is a considerable volume of data on the relationship between the strength of a cube. tested on its side, and a cylinder.The best average estimate is that the cube strength is 25% greater than the cylinderstrength.

The conversion process is as follows.

Hence 1(a) to 1(b) The difference between the strengths of these s::ecimens is associated with the direction of drilling. On the strength of 3(a) = 125 x the strength of 2(b) average, the strength of a core drilled vertically is about 8% 2 Sp  !

greaterthan that of a core drille.1 horizontally. lf the strength =

of 1 (a) is p. the estimated strength of 1 (b) is 1 08p. 1 5 + 1/A

• i 1(b) to 1(c) The effect of the length / diameter ratio upon it may be noted that if A = 1. the strength of 3(a) = p.

• core strength is such that This means that the strength of a core of length / diameter  ;

. ratio 1. drilled horizontally, is similar to that of a cube: this l.

2 '

is in line with evidence provided by tests made upon cores the strength of 1(c) = 15 + 1/A x the strength of1(b) drilled from cubes.This is summarized in Table 7. .

21.6p

=

The Estimated Actual Strength.f.ais,therefore. yielded l 15 + 1/1 by the equations: -

1(c) to 2(a) The difference between the strengths of these i specimens is associated with the fact that the cylinder has *

/,, -  ;

a cast. rather than a cut. surface. Experiments have indi. 1 5 + 1/A  ;

cated that a specimen with a cast surface has a strength at;out 6% greater than the core.Therefore, if cores are drilled in a horizontal direction- f the strength of 2(a) - 106 x the strength of 1(c) 2 3/x ,

f," ,1 5 + 1/A i 2 29p

~~ '

1 5 + 1/A if ceres are drilled in a venical direction.

i

=

j "i Table 7 Evidence on relationship between core strength and cube strength. I Ref. Cube size Core diameter L/O of cores. Core strencth Accroxirnate cube Cuos strengtn strength (mm) (mm) 1 (N/mm8) 5 p' 200 2. " 5.0 1 12 1 04' 10 to 50

.f 30 150 and 200 100 and 150 1 6t and 80t

1. 1 03 t 60 49 4 ** 150 4 100 1050 275-1 0 97 30 0 to 0 36 200 1 150 1 00 12to70 32and35 150 70 and 100 1 1 04 25 and 60

• e , . 8

,,g f5ble 11 Relative strength of cores from structures and test cubes.

Dire:. ion Core strength Core strength 28 day Age of cores R ef.

cf orEng Cytander sitengin Cuce strengtn cube strength (N/mma) , (days) 0 89 (0 71) 16 to 39 28 10 .

U I g"3r 0 94 0-89 16 0 84 0 74 31 ,

28 48"8' 0 75 0 64 49 0 91 (0-73) 44 93 81 0 79 (0 63)

Vertical 0 81 (0 65) 23 90 102*

0 63 (0 50) 47

. 0 70 (0 56) 36 30 86* .

0 77 (0-62) 32 .

0-82 (0 66) 27 93 6 0 88p (0 70) 44 91 114*

(0 88) 0 71 35 34 70"'

0 85 (0 63)

• 37 93 81 0 81 (0 65) 0 73 (0 58) 27 93 6 Horizontal (1 13) 0 91 68 (1 10) 0 88 52 (0 89) 0 71 45to75 28 32*

~

0-85 (0 68) 37 91 114 Both (Ges). 068- ,- 28 121m Notes ,

(1) Cores taken from full depth of slab - (6) Cores tested in dry condition ~

(2) Cores tested in moist condition (7) Results based upon tests on 24 s'tes (3) Core strengths corrected from :ssults of tests on cores with1 = 10 (4) Core strengths corrected from tesults of tests on cores withl = 1 1 (5) Core strengths corrected from results of tests on cores with1 = 3 0 Table 12 Relative strength of standard cylinders and Table 14 Relative strength of concrete from actual cops from structures."" structures and in cubes.non in strengt.*

Sement u er ean cf Actu Strengtn st e inders res , pgt n alSn (N/mm8) (N/mm3) (%)

20 19 5 Columns 3 0 68 30 27 10

• Watts 2 0 59 3

Slabs 2 0 45 4

• Figures mathematically inconsistent

. Table 13 Com;3arison of strehgth values yielded by use of formulae reccmmended here for Potential Strength and by use of data in BS 1881.

Metnce Direction of drilling Hon: ental Vertical

%=1* 1 = 1 2* 1=2 1=1* 1-12* 1-2 A: Forr u:ae 130A 139A 162A 12CA 129A 1 5C/1 B: BS 1681 1 15A 1 17A 125A 1 15A 1 17A 125A

. . s.s .. . 1.< .

flq:1 lie. Kelv re,w c 2 Aga propcolles of Concrete in indirect tension.8 " Fig. 8.19 shows the retation between mean st rength '

g 492 Properties ofConcrete P00RORGNa and specimen site for cubes, and Table 8 4 gives the relevant values for in a greater number to give the same precision of the mean: Twe

!lI 100 mm(4 in.) concrete cubes would bc ecquired imiend ot'thace 15 in. .

(6-in.) cubes;'" or five 13 mm ().in.) montar cubes insicad of two O 2 4 G 0 10 100nominnfly from mm (4 in.) similar cubes batches.'" from the same batch or four 100 3 &A'kroyb ,$/Ib[* t # t#

• s norman g ,

s F 1' 10 5 o.

o neae f Jy" '('n.

<t s o b ,,

(

b"CLU w t' *1 iYu i 3 4 "*Y U 2 .. ,, ,, ., n ya ..

• " * ' Y~

3 kl .

e (.

') 6000 f.} _

.. - . . .-. . _ L. ti$tt bl* -

1 -

h. , c o 2. 's y + *./..**... c -

g;100 e

, a ~E '

e' 5000 3,

• j n-30

,e ,.

[/ ~

3 95 ' ( g,Y', ./, 4000 2

• I" -->f'*.- #

$ N

' L s,. /*/'~ ~

fr t%

.? 20 s'oY o

(

3000 N 9 $

8[* ',/ I"'* [150s tSOmrdG= 6n) o 51 maam - a...a Q Cube site -mm j 5 *--* ~

,roo ".'co"'n "ce e"."3 . .. 2000 C rtg. a. 9. Conorressive stre'Wth ofcut es of liferr"! sise>" )

^

d p/p~ , ,, O

~"' k r,3g,,gg,,,

oo.comnte.rns --,

standard deviation. Prisms * *' and cylinders exhibit a similar be. c,, , f,3o.,ngs , , ,,,, jooo .

haviour (Fig. 8.20).The size cirects arc, of course, not limited Io concrete, , 12oo, nce,,s . . ,

and have been found also la anhydrite ** nnd other materials.

0 l I It is interc' sting to note that the size clTect disappears beyond a certain 7mys pg

• o 3 * ""'S size so that a further increase in the size of a member does not lead to a trear

.h icar in strength. According to the llureau of Reclamation,*" the #

Fig. s.21. i strength curve becomes parallel to the size axis at a diameter of 457 mm si,c* a (ng,;ferr io f,f f

,7"{,'

)

• "[,3' ""9' " 9 5"'d'I"d'# '"'T'A */ veri">

(18 in.), i.e. cylinders of 457 mm (18 in.),610 mm (24 in.), and 914 mm (36in.) diameter all have the aame strength. The same investigatioit 8fcc/ men Sizc am/ sggreg,f, gf,,

It.

Indicates that the decrease in strength with an increase in size of the . is clear thni a test specimen has to be appreciani I ,

specimen is less pronounced in lean mixes than In rfcle ones. For instance, largesi size orihe aggregnIe particles in the concrete' y the strength of 457 mm (18 in.) and 610 mm (24 in.) cylinders relative to i """* - #'

recommend different va'ues for the rn:io of the mini " "

152 mm (6 in.) cylinders is 85 per cent for rich mixes but 93 per cent for lean (167 kg/m'(282 lb/yd')) mixes (cf. Fig. 8.20). '

'['# 8c58 Specimen to the maximum t - l n

af8' gseg These experimental data are ofinterest as it could be specula'ed that, (1 in.) nygiegate is used, i.e. a :atio of l. A.S.T.M. Sinndard C 192 if the site c!Tect is extrapalated Io very large structures, a dangerouslylow intilt the ratio of the diamer, i 011he epid.r m m %, ,

strength might be expected, lividently this is not so. sire to 3. and the U.S. Ihneau -)f iteclanmtion to .l. A vuhic it ,ft***"

The various test results on the sire citect are ofinterest because in the 3 8"?I 4 n pencrally accepted as satisrocimy,

.t he h.

mitation of site niiscs from the " wall ctrecia (f effp, ,fg py,,j),

... ~

• - - - :< g 5? " 5 Fd i W Q . -ME mmEWameww'3GYY%j$g L-

'a-cc.hSThi.fl' i ."

p"'" ./ 7 Hy l-s m =2 un b-b 9M q gg i

DIscesStos ox Montrrr.n Cear COsIPRESSION

@Q MTESr Q g ew@a 415

1. c h p <rm - -- w l

1. ."e.fm riby C t I, byMzssts. the H.two J. Grtmt me.thods of test can be mo '

q gi,e u definitely

.,e

?y@!.. -

n .-.' .A d

t e, & ff5.k,m

. 2 this paper first became available, the writers were laying o tAxo Gr.tx u a series kN~ ,,

g of compression tests on a large number of 2-in. cubes, 3 by 6 in %N%N^

cylinders 12.in. control specimens. and 2 by 2 by 4-in. prisms (side cast) along g@tf with

'j% a'few 6 by g

therefore, to tests paralleling those per. described Results in they% dhpjg J paA number of 9

t from these tests are tabulated below: tM g gu-r 4 9$C

+

l,d.'E 7.dar Tasas

34 tar Tsuis [ ~

%#6 T. ' '

Pria:ns, * : i*/.q DORw j 1 by 2 dr o la.

P,isine as Mau$a.

Caben.

3 m.

Prisma, 2 W 3 Dr 4 in.

'P,iese as Meeiled Ciben, Crna.

ses eyne.

ders l ,c s// pprf $ p - .-

~* 1 Cases 2 is. 1 by 6 . (*; t's h.sasbar el tarta. . . .., . . ... . . 8 by 12 As esase stregt.a. A per sq. la.. 12 16 Cuous in. ha.

• J) %r. , r .

f$te# 7,,

4 14

• h.. .,sf s ..s.3 Q<. . . = -t i

P.ane se p ra strong.A 3033 3C:0 24 8 - ) .. ,,u;&

l 60

. w-- . yr.

25408 5373 8 Maa. r:resch asy sp-.. . .Ib. ... 1.00 1.03 0.37* 1.00 47;.J 1040, 4390 2 .

per se. as...., .. _

Man. Au:4u aa . . . . .

3270 3400 1.03 LOS 1.00 5280. s 0.98 M*'tgA

& e 4 ./" . w p-& **

purst,sa ...r s;iseunes. A 3440 1173 8200 6213 &l00

" "5%

M8";

, ',;.e,.4.g

,4. ,

ePowr wn

• SC4 2800 rfte 4100 337.8 5000 5330

g u ;**g. Y2- &

.;yD,,

-'~

' *.'nf.-*

- 'g. , ?,d w..i.,_c.b 5410 1:33

.y a [p i -Yd:-Ja.#-d *r ar  %

. twice de lata sidsmannsa

- w.u-,,,a.a.,i .ad.,-

.cs.4 l'ita^'

ef I --

)["%.Mr.

"$$h. W,*n.e-Q, T ae'71 4% .> '*M e --S 3/'4.mch 4 i S Lnra-'i.5 3 l 'w y g n c, ..a.n :... .O.-

Support is found for conclusions Nos.1,2,3,4, and 8

> _,,,s- -

.s *3

. - 8:,- .* e w ~:1 n. :.yw n.,:,

gtp"t. .q" M.

<,.H M.y ..M.z-er.

As a check on conclusion No.1, for half of the 24 prisms tested ,,g,f-1 cubes length and the for themodi others, as 5ed the end cube 2 in. was taken as the middle -

as di h.y@.- . t.%g,_r'*

2 in. of.jhth Moreover the zone of h ' 9W damage does not (for the mortar used) extend beyond picked for the cube. Yt.$k the boundary . MMb as an end 2 in. of the prism, the other 2 in. was M $, undamaged

$%pt.,

i, a

Nt-3 virtually the same strength as the end tested first .

ve JEW-p

t.

strength of the fragment was higher rather than lower.Sometimes the Still more 3 NP .,

- i 2

test when the middle 2 in. were used as K'hMk the cube 'Q,,, gav f$

equalled that of the middle 2 in. at the original test.

cube should be weaker than a cube.It is dif5 cult to understand why a which

~

N(N

[,M'g d{ +f F.

O

p.j{$li.N3@9;g)(h $6 mentioned at the bottom of page 409 of the paper, that cibes areIt is com m.ysy#p $ t

!. *2 g e notwithstr.nding). Thus while the evidence Fp available h se

d .W.g@w.g.

p g conclusion No. 3, a satisfactory explanation is not yet apparent ,

G AW %gg4 d Profensor,respec .s h'2.h@m gg;;:

3.uMEMh'2 9

Monar.ics. Io.s S.a:a Col:ess, Amas. Iowa.s rrefessztand Head, and Anaist.ast n:-

. .partmentof teoretic.!and AppNed t "Wm -mms! '

.l. 'I, h . '

. .e :23 hh' h,.g.;.

YD'k.

-.'4 .t:-W *y. .,d@ GIN-3'8

^i

• E

.6 " .*.

s. r* ;mj-jf,f-Q 6.?'

j 7Q @n '~y

U

.A. k.;.: y y w ' b~ y Y 1 S .

$ W$ty:=> *.79.*.%'-

I

- M.*

.N"v"'itl

~~

ge j - . p g . .#? :.T'%.4.,. M@a$ ra>!;

.f,- ".'s..- -" eN **w"M 9=; . e Q  ;^. GD y

.a'm

.w.

.n m.on.n.-pmsgm -

w M* r nww" - -

w~

APPENDIX E "POSSIBLE CAUSES OF RETROGRESSION OF STRENGTH OF CONCRETE" e

1050 279

Contituction technology Inbo<otorlu Possible Causes of Retrocression of Strenoth of Concrete ,

There are several possible causes of retrogression of strength of concrete.

1. Unsound cement due to an excess of free lime, magnesia, and/or calcium sulfate.

2. Alkali-silica and alkali-carbonate reactions.

3. Sulf ate attack.

4. Leaching of lime and soluble alkali salts from the Concrete.

5. Other deteriorating exposures, i.e., freeze-thaw, acid, etc.

None are considered to be pertinent to the reported retrogres-sion of strengths o8 concrete cylinders between the ages of 28 and 90 days.

Neville(1) discusses Item 1 in his book " Properties of Concrete," p. 50, copy attached. The autoclave expansion test specified in ASTM C-150 guards against excess magnesia, and free lime, and the 503 requirement guards against excessive sul-fate. The Ash Grove cement used in the construction satisfied all requirements of ASTM C-150.

Item 2 - Alkali-silica and alkali-carbonate reactions can cause loss of strength at later ages, generally noted af ter a good ,

number of years. ASTM C-342 "A Test Method for Potential Volume Change of Cement-Aggregate Combinations" is a method designed to accelerate such reactions, if any, so that they occur within a period of about one year.. .We did not run this test because low alkali cement was specified and used and no evidence of deleterious reactions was revealed by microscopic examination.

Item 3 - Self ates from soil and water may react with hydrated calcium aluminate to f orm calcium sulf oaluminate, causing expansion and deterioration of concrete. The concrete under discussion was not subjected to these conditions and no evi-dence of such reactions was observed.

Items 4 & _5 - There was no opportunity for leaching or delete-rious exposures in the subject concrete cylinders, Items 2, 3, 4, and 5 are briefly discussed in the BuRec Concrete Manual, Pages 7-11, attached.

1050 280

construction technology laborotonics Conclusions .

We do not have any explanation for the reported retrogression of streng th between 28 and 90 days, other than faulty handling and testing procedures and we can not readily identify these.

J. J. Shideler, Director Administrative and Technical Services JJ5/md CT-0539 February 27', 1979 9

O e

1050 281

- ~

300R ORGINAL 50 Proprrties of Concrete Portland Cement $I ,

with another glass plate.The whole assembly is then immersed in water at fo!""/"'32- 18 to 20*C(64 to 68'F) for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />. At the end of that period the distance it is essential that a cement paste, once it has set, does not undergo a large change in volume. In particular, there must be no appreciabic between the indicators is measured, and the mould is immersed in water expansion,which under conditions of restraint could result in a disruption 1 again and brought to the boilin 30 minutes. Afler boiling for one hour the of the ha:Jened cement paste.Such expansion may take place due to the mould is removed, and after cooling the distance between the indicators delnyed or slow hydration or other reaction of some compounds present in the hardened cement, namely free lime, magnesia, and calcium sulphate.

e IfIfic raw materints fed into the kiln contain more lime than can com- .

hine with the acidic oxides, the excess will remain in a free condition.  : .

This hard burnt time hydrates only very slowly, and since slaked lime

{ g occupies a larger volume than the original fres calcium oxide, expansion  ! ,y . . . .i ta kes place. Cements which cxhibit this expansion are known as unsound.  %- -j ;(;# * '

Lime added to cement does not produce unsoundness because it hydrates rapidly before the paste has set. On the other hand, free lime present in clinker is intercrystallized with other compounds and is only partially exposed to water during the time before the paste has set.

Free lime cannot be determined by chemical analysis of cement since it is not possib!c to distinguish between unrcacted Ca0 and Ca(Oll),

produced by a partial hydration ofIhe silicales when cement is exposed to the atmosphere. On the other hand, n (cst on clinker,immediatelyafter it Fig. I.23. De h CAaretter affaratus has left the kiln, would show the free lime content since no hydrated cement is then present.

is again measured.The increase in this distance represents the expansion A cement can niso be unsound due to the presence of Mgo, which of the cement, and for Portland cements is limited to 10 mm. If the reacts with water in a manner similar to CaO. Ilowever, only periclase (crystalline MgO) is deleteriously reactive, and MgO present in glass is expansion exceeds this value a further test is made after the cement has harmicss, been spread and acrated for 7 days. During this time some of the hmo Calcium sulphate is the third compound liabic to cause expansion: may hydrate or even carbonate, and a physical breakdown in size may in this case calcium sulphoaluminate is formed. It may be recalled that n also take place. At the end of the 7 day period, the Le Chatelier test is hydrate of calcium sulphate-gypsum-is added to cement clinker in repeated and tl.e cxpansion of nerated cement must not exceed 5 mm. A cement not satisfying at least one of these tests should not be used.

order to prevent flash set, but if gypsum is present in excess orthe amount Th" I" ChalClicf test detects unsoundness due to free hme only, that can react with C3 A during setting, unsoundness in the form ora slow -

expansion will result. For this reason, ILS.12: 1958 limits very strictly the

-.MagacMa_itmdtmient in large quantit es m the raw matenals from which cement is manufactured in linrjand, but is encountered m other amount of gypsum ; hat can be added to clinker, but the limits are well on 2 countries.* For this reason. in the United States for instance, soundness the safe side as far as the danger of unsoundness is concerned.8 "

~~

Since unsoundness of cement is not apparent until after a period of _orcement is checked by the nutoclave test, which is sensitive to both free

, mannesia nnd free lime, in this test, prescribed by A.S.T.M. Standard C-') mnnths or years it is essential to test the soundness of cement in an C 151-71, a neat cement bar 25 mm (or i in.) sc}uare in cross-s:ction and w ::ccelerated manner: a test devised by Le Chatclier is prescribed by with n 250 mm (or 10 in.) gauge length is cured n) hunud air for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br />.

c--) U.S.12:1958. The Le Chntelicr apparatus, shown in Fig.1.23, consists of The bar is then placed in an autoclave (a high pressure steam boiler),

a small brass cylinder split along its generatrix. Two indicators with which is raised to a temperature of 216*C (420*F) (steam pressure of N poinied ends arc attached to the cylinder on cither sidc orthe split:in this CC) manner lhe widening of the split, caused by the expansion of cement,is

• An exempte't: India,when law.manneste timesione occurs only to e limited essent. The resuhina ecment hn thercrore a high biso content but esponsion can be signincanity N greatly magnified and can be casily measured. The cylinder is placed on a reduced by the addislon of actlve alliccous material such se pulverited fuct ash or tinoff glass plate, filled with cement paste ol' standard consistence, and coverct! ground burnt clay. ,

~

52 l'rnperties of Concrete P00R BR W L '

Portland Cement 53 8 per cent of the weight ofIhe solids is mixed and moulded into a briquelle i 210 07 M N/m'(295 lbfin'))in one hour,and maintained at this tempera- of the shape shown in Fig 1.24. The sand is the vandard Leighton ture for 3 hours3.472222e-5 days <br />8.333333e-4 hours <br />4.960317e-6 weeks <br />1.1415e-6 months <br />.The capansion of the bar due to autoclaving must not Ilunard sand obiyined from a quarry near the villade of that name in '

exceed 0 5 per cent.The high steam pressure accclerates the hydration of ,

Dedfordshire. Tins sand consists of pure siliccous material and is hoth magnesia and lime. practically all of onc size; nll particics are ncarly spherical nnd arc smalle The results of the nutoclave test arc alTected by, in addition to the_ l than n 850 pm (No.18 B.S.) sieve and at least 90 per cent of the sand is compounds causing expansion, the C3A content, and are also subject to l retained on a 600 pm (No. 25 D.S.) sieve.

other anomatics. The test gives, therefore, no more than a broad indica.

tion of the risk oflong-term expansion m practice." l *

• No test is available for the detection of unsoundness due to an excess of a

, calcium sulphate, but its content can be casily determined by chemical _

analysit. _ i g

. . _._. . ..... . g Strength of Cement The mechanical strength of hardened cement is the property of the l $

y material that is perhaps most obviously required for structural use. It is E not surprising, therefore, that strength tests are prescribed by all speci. 4 fications for cement. I The strength of mortar or concrcle depends on the cohesion of the cement paste, on its adhesion to the aggregate particles, and to a certain II W. einrepr th re,,sto,e rest y- rror extent on the strength of the nggregate itself.This last is not considered at this stage, and is climinated in tests on the quality of cement by the The briquettes are moukled in a riandard manner, cured for 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> use of standard aggregates. at a temperature between 18 and 2 ' C (64 and 68*F)in an atmosphere of Strength tests are not made on a neat cement paste because of difficul. at Icast 90 per cent relative humidity and tested in direct tension, the pull ties of moulding and testing with a consequent large variability of test being applied through specialjaws engagir,g the wide ends of the bri-results. Cement-sand mortar and, in some cases, concretc ef prescribed quette. D.S. 12: 1958 prescribes the minimum one-day strer gth of rapid proportions and made with specilied materials under strictly controlled hardening Portimid cement ns 21 MN/m3 (300 lbfin'), taken as the conditions are used for the purpose of determining the strength of average value for sla briquettes.

cement. There are two standard methods of testing the compressive strength of There are several forms of strength tests: direct tension, direct com.-

cement: one uses morf ar, the other concrete.

pression, and flexure. The latter determines in reality the tensile strength In the mortar test, a 3 :3 cement-sand mortar is used.The sand is ngnin m bending because, as is well known, cement paste is considerably the standard Leighton Uuzzard sand, and the weight of water in the mix

' stronr 1 in compression than in tension. Since the flexure test is not is 10 per cent of the weight of the dry materials. Expressed as a water /

used in Great liritain and littic used elsewhere it will not be further - cement ratio this corresponds to 0 40 by weight. A standard procedure, discussed. prescribed by D.S.12:1958,is followed in mixing, and 70 6 mm (2 78 in.)

- The dircci tension test used to be commonly employed but pure tension cubes are made using a vibrating table with a frequency of 200IIz o ais rather difficult to apply so that the results of such a test show a fairly -

npplied for two minutes. The cubes are demoulded after 24 hours2.777778e-4 days <br />0.00667 hours <br />3.968254e-5 weeks <br />9.132e-6 months <br /> and Ln large scatter. Furthermore, since structural techniques are designed further cured h water until tested in a wet-surface condition. The O mainly to exploit the good strength orconcretc in compression, the tensile U.S.12: 1958 requirements for minimum strengths (nverage values for st rength of ecment is often oflesser interest than its compressive strength. three cubes) are given in Tabic 1.it IN For these reasons the tension test has gradually given wayIo compression The vibrated mortar test gives fairly reliable results but it has been CD Icsis. suggested that mortnr made with one-size aggregate leads to a greater U llowever, the tension test has been retained in D.S. 12:1958 as a scatter of strength values than would be obtained with concrete made permitted test for a one-day strength' of rapid hardening Portland under similar conditions. Morcover, the vnlues of strength obtained in a cement. In this test a 1:3 cement-sand mortar with a water content of s

t

[

l ProArties of Concre e i

\

To Oh!11allain A M Neville MC, TD, DSc(Eng), l'hD, MSc, CEng, PEng, FICE, FIStructE, MSocCE(France), FAmSocCE, FACl, FI Arb Professor anut lleatl of Departanent of Civil Engineering, University of Lee:Is, fortnerly Dean of Engli..cring, University of Calgary

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Cor4CnETE mar 4UAL

• CalAPTER l-COriCHETE Ar4D COr4 CRETE MATEfuALS 7 the same slump. In the two views at the right, the specimens have been is restricted by specifications to 2 inches for concrete in tops of walls, .in tapped with the samping rod as prescribed in designation 22. The,Xon- piers, parapets, curbs, and slabs,that are horizontal or nearly horizontal; crete in the upper siew is a harsh mix, with a minimum of Ipes and 4 inches for concrcic in nreb4nd sidewalls of tunnels; and 3 inches for water. It may be cilicient for use in slabs, paveinents, or masy concrete concrete in other pmtspf' structures and in canal linings. The slump of a where it can readily be consolidated by vibration, but it wo71d be quite mass concrcic is us unsuitable for a complicated and heavily reinforced placen;cnt. The con- cannot be placept (juilly restricted nhout execeding specified slumptolimitations, a maximum of 2tn it may bc Oinc crcle in the lower view is a plastic, cohesive mix; the sur is needed for a dillicnit placement. Ilowever, if ititcan is use/gflus concluded thaj4hc mix proportions nre in need of adjustment. The mini-workability where be /

mum sluml that enn be used, commensurate with desired workability, casily placed and vibrated. such a mix would be ipflicient because it requires tbe Icust amount of cement and water, in general, the wetter the it is evident that, contains while measurement excessesof slump ofgives cement, lines, a valuable indicatand water. Thp, ion of consistency consistency, the greater the tendency toward b! ceding and segregation of coarse aggrer/.c from inc mortar.

workahility and etliciency of the mix can be j diged only by how the

6. Durnhility,-A durabic concrete is one that will withstand, to a sat-concicte goes into place .m cach past of the strup ure and how it respon is is

. factory degrec, dic cKccts of scrvice condit. ions to which it will be sub-to consolidation by good vibration. Ellicientjmixes do not have much .

surIilns workability over that needed for ood results with thorough Jccted, such as weatherm, g, chemical action, and wear. Numerous labora-vibratm, n.

tory tests have been devised for measurement of durability of concrete, The influence of temperature on the sh up of concrete is indicated in out it is extremely dillicult to obtain a direct correlation between service figure 3.  ;

For llureau of Reclamation work, th maximum permissible slump of (a) H'cailsning /kil.iqmcc.-Disintegration by wenthering Is caused concrete, after the concrete has been l'eposited but before consolidation, mainly by the disruplive action of freezing nnd thawing and by expansion and contractson, under restraint, resullmg from temperaturc variations 1 and alternate wetting and drying. Concrcic can be made that will have i l N [3ch point represents f the aversgo obtained cxcellent resistance to the cifccis of such exposurcs if careful attention 6 \ ' * " is given to the sclection of straterials scul to adi other phases of job control.

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el th thInchmas,aggregals The purposeful entrainment ,OI sm ll bubbles of air, as discussed in section 14(b), has niso helped to improve concrete durability by de-3 s g

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' is also important that, where practicab!c, provision be made for adequate drainnge of exposed concrcic surfaces.

7 ' N .,.

Much has been lenrned regarding the resistance of air-entrained con-g3 s N cretc to frost action, especin!!y with respat to the influence of internal

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porc structure on durability. Dry concrete, with or without entrained air, 111h 0-Inch aan.aggrejate N'N sustains no damaging cliccis from freezing nnd thnwing. Non-air-en-trained concretc with high cement content nnd low water cen.cnt ratio 1 - [ (0.361) develops good resistance to freezing and thawing primarily W6a p opo atIons aalnIalned censtent Ior alI t 1peraturas because of its relatiscly high density and attendant high impermeability o (or Wnterlightncss) Which reduce the free (or frCcZnble) Water nynilabIc 40 50 00 70 60 00 100 to the capillary system nml/or through inflow under pressure. Ilowever, IEM[R A tURE, DECREES FAlf REHitEli within the usual range of water-ccinent ratio specified for exposed Struc-gliral concrctc (maximum 0.47 to 0.53), grcntly increased resistnnce to rigurn 3.-Itclationship betwocn slump and tempornturo of concreto mndo Irreling Hild tilawing is elfected hr ute ptirposeful cuiraitunent of air, whh two manhnum stres of acnrcentes. As tho temperatura of tha incredients increases, tho stump decreases. 200-D-1000, This entrainment, in the form of multitudhious nir bubbles rnnging in size from lc5s than 20 microincters (subinlcroscopic) to about 3,000

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,10 - coricrtCTC MANUAL. j CHAPTErt 1-CONCnETE AND CONCftCTC MATEftlAt.S 11 dicaleil. an appropriate smInce covesing or treatment should be i We 2.Wuck on concrete by solls nnd wnfers enntnining ynrious emid opd. sulfate concentrations ,

When cement imd uater combine, one of the compounds forme.' -----

, ,, p is h3drateil lime, which is readily dissolved by water (often made an.s k

, p ,,9 t.ssadin wn amenci sa nne s mries mine argoessive by the presence of tlissolved emhon tiiusille) passing NcC llgible .............. D.noto 0.10 0 to 130 through cracks along unproperly treatetl construction plancs, or

• Positive ' . . . . . . . . . . . . . . 0.10 to 0.20 130so 1.300 thumeh interconnected voids. The removal of this or other solid ma- Sevcic' .......... .... o.20 to 2.00 1.500 1o 10.000 terial by teachinc.may seriously impair the ymdity of concrcle. The ve ry se ve re ' . . . . . . . . . . . 2.00 or more 10.000 or more

... w hite 'd7 pour $tilorescence, commonly seen on concrcic surfa'ces -

is the sesult of leaching and subsequent carbonation and evaporation. M 'Ir7."v"O'"d;.i. iw . pre na corn.r.: .,onotaa ce=<ai ren knas compuawe .tr.a (2) Certain agents combine with cement to form compounds "%."'Er["'y "7,Nc'n"t pI"'.".$,..e4 po,,otam shich has been deterndned try which have a low solubility but which dNopt the concrete beenuse ""**"' ""*"'""d'"'*"'""**'"""***'

their volume is greater than the volume of the cement paste from these reactions are accompanied by considerable expansion and dis-ehich they were immed. I isintegration may be attributed to n com- , ruption of the paste. Figure 5 illustrates the effect of sulfate attack hination of chemical und physical forces. In dense concrcles this on concrcic in a canal lining and a turnout wall. Concrete contain-type of attack unuhi be largely superficial. Porous concrete would be ing cement with a low content of the vulnerable calcium aluminate is aliccted throughout the mass. Most prominent among aggressive sub-highly resistant to attack by sulfalc laden soils and waters. (Sec sec.

stances which alTect llureau conciete structures nre the sulfates of' sodiom, magnesium, and calcium. These snits which are known us 15(b).) The relative degrecs of attack on concrctc by sulfates from soils and ground waters are given in table 2.

O white alkali nre frequently encountered in the alkall soils and ground (3) Where concrcic is subjected to alternate wetting and drying, Ln waters rf the western half of the United States. certain snits, such as sodium carbonate, may cause surface disin.

O The stronter the concentration of these salts the more active the tegration by trystallizing in the porcs of the concrcle. Such action corrosion. Sulfate solutions increase in strength in dry seasons when appears to be purely physical.

dilution is at a minimum. The sulfates react chemically with the

,,,3 hydrated lime und hyttrated calcium aluminate in cement paste to (4) In environments such as flash distillation chambers of de-salination plants where concrctc is exposed to condensing cool-to-form calcium sulfate and calcium sulfoaluminate, respectively, and hot water vapors or the resulting flowing or dripping of distilled jit(lW3 f"7; $$ -' ' ' water, the concrcic is rapidly attacked by this mineral-frec liquid.

I' Tl The liquid rapidly dissolves nynilabic lime and other solubic com-(

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$- pounds of the cement matrix. Subsequent rapid deterioration nnd cventual decomposition result. The only palliative knowa at this h,T - [' i ,, d..yd..).') *(. .

l hk.AD f ..

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, time is complcle insulation of the concrete from the mineral-free water by coatings or lining materials which are not aficcted by the Q h/ ! c g .7' I ' N F 2- M

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1 (5) Concrcic in desalination plants is adversely affected by the fred water, sea water, or brine from wcils. At these plants, high.

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, 4,Q.,, ,,$ g t quality concrcic has been found unsuitnb!c for use in brine exposures at temperatures of 290* F but suitable at 200* to 250' F provhled

. s ndcqunto sacrificini concreto is mndo nynilable for surface deteriorn-

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tion. Fielow about 200* F no provision for sacrificini concrcic is gen-YS y L F .i y. U.f ..G r[ ' .iy,S'y;  ;.p. crally required. Deletioration such as occurs at the higher tempera-

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( s Mi ture is a chemical niteration of the peripheral concrete paste which

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results in extensive microfracturing with resultant reduction of com-Figure 5.-Disintegration of concreto caused by sulfato attack. PX-D-32050. '

.