ML102870920

5.1 Contamination During Construction

ML102870920
Person / Time
Site:	Crystal River
Issue date:	01/13/2010
From:	- No Known Affiliation
To:	Office of Information Services
References
FOIA/PA-2010-0116
Download: ML102870920 (2)

Text

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5.1 Contamination During Construction

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Description:==

During construction operations it is possible for contaminants to get mixed with the fresh concrete. Some of these materials have the potential to weaken the concrete and/or affect its durability. Source of contamination can be dirty aggregate that may include organic material, fine dust, or other reactive elements. Another source is construction related material such as grease/oil, nails/ties, tools and safety items, clothing, cigarettes, food, and other debris.

Foreign material can impact the concrete by either replacing sound concrete with weak/incompatible filler, or by adding reactive elements that react inside the concrete. Contamination can be detected by inspections during construction, visual inspections for signs of distress such as spalls and cracks, and analysis of concrete removed from the structure (during demolition and coring).

Precautions involve strict control of aggregate sources, good construction and safety practices, and an effective Quality Control (QC) program that monitors potential for contaminations.

Data to be collected and Analyzed:

1. Review project specifications for requirements.

2. Review project QC procedures.

3. Review aggregate evaluation from original construction (FM 5.1 Exhibit 5 is a report by Law Engineering)

4. Review Non Compliance Reports. (NCRs)

5. Review Petrographic reports for signs of contamination.

6. Review inspection records (IWL), observations during demolition, and core inspections for indications of contamination.

Verified Supporting Evidence:

a. Exhaustive review of NCR reports revealed an incidence where sand was found inside concrete forms. (FM 5.1 Exhibit 3) QC procedures failed to detect the contaminant (FM 5.1 Exhibit 4) and corrective measures were needed to repair the problem.

Verified Refuting Evidence:

a. Project specifications included cleaning requirements. (FM 5.1 Exhibit 1)

b. Project QC specifications provided requirements for preventing contaminations and for proper inspections and reporting. (FM 5.1 Exhibit 2)

c. Tests on original aggregate by Law Engineering (FM 5.1 Exhibit 5) found no clay lumps. There was no mention of any organic impurities or excessive dust.

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5.1 Contamination during construction (cont.)

d. Multiple Petrographic reports on concrete cores taken in 1975 and 2009 did not encounter contaminants (FM 5.1 Exhibit 6). The Erlin Hime report (FM 5.1 Exhibit 6b) noted dusty aggregate and recommended that it be washed prior to use.

e. Exhaustive review of inspection reports (IWL) found no indication of spalling or cracking that could be attributed to contaminants.

f. Detailed review of cores taken during 2009 found no indication of contaminants. Thorough analysis of photos taken during and after the SGR hole cut demolition did not detect any signs of contamination in the concrete.

Discussion:

The evidence presented above describes a system that provided guidelines and inspection tools needed to prevent contamination of the concrete. The single report discussed in FM 5.1 Exhibits 3 & 4 of contaminant in the concrete also describes the methodology for removing and repairing the contaminated concrete.

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Conclusion:==

There is no evidence of undetected contamination during construction and it was not a contributing factor to the delamination.

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