Analysis and assessment of microbial biofilm-mediated concrete deterioration.

Details

• Creators:
  Trejo, David ; de Figueiredo, Paul ; Sanchez, Mauricio ; Gonzalez, Carlos ; Wei, Shiping ; Li, Lei
• Corporate Creators:
  Texas Transportation Institute
• Subject/TRT Terms:
  • Biodeterioration
  • Concrete bridges
  • Foundations
  • Piers (Supports)
  • Bridge piers Concrete--Biodegradation--Texas
  • Concrete bridges--Texas--Foundations and piers
• Publication/ Report Number:
  SWUTC/08/476660-00008-1
• Resource Type:
  Tech Report
• Geographical Coverage:
  Texas
• Edition:
  Technical report; Sept. 2007-Aug. 2008.
• Corporate Publisher:
  Southwest Region University Transportation Center (U.S.)
• Abstract:
  Inspections of bridge substructures in Texas identified surface deterioration of reinforced concrete columns on ; bridges continuously exposed water. Initial hypothesis were that the surface deterioration was a result of the ; acidity of the water in which the columns were exposed. However, evaluation of the water acidity indicated that ; the surrounding waters were only very slightly acidic and near neutral. Discussions between engineers from the ; Texas Department of Transportation (TxDOT) and researchers at Texas A&M University and the Texas ; Transportation Institute (TTI) hypothesized that the damage could be a result of microbial attack. Microbial ; attack is often identified as an acid attack because some microbes can produce sulfuric acid. This research ; investigated whether microbes were present at areas on the bridge that were exhibiting attack, determined if ; there was a correlation between degree of damage and number of microbes present, determined if these microbes ; were acid producing microbes, and identified the microbes present at the field sites. Results indicate that ; microbes are present at the bridge columns experiencing surface deterioration, that the number of microbes ; present is directly correlated with the degree of damage, and that these microbes are acid producing. The ; research identified five genera: these included Bacillus, Brachybacterium, Flavobacterium, Lysinibacillus and ; Thiomonas. The group with the largest numbers of representatives was Bacillus, which was composed of 17 ; strains. The second largest group was identified as Thiomonas perometabolis, which consisted of seven strains. ; The researchers concluded that the damage to the concrete bridge columns is microbial attack. Because some ; bridge structures are exhibiting significant microbial attack of the concrete cover and because the long-term ; performance of the columns (and hence bridges) are most sensitive to concrete cover, further research is needed ; on how to prevent and mitigate this attack.
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• Format:
  PDF
• Funding:
  DTRT07-G-0006
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/16891/dot_16891_DS1.pdf
• File Type:
  [PDF - 1.63 MB]
• Collection(s):
  University Transportation Centers ; US Transportation Collection
• Main Document Checksum:
  urn:sha-512:c391e134a1e617cd7542c421025650eaebec9b448de881338ed58bc24e9e9542ed1ea889441239ece694ffea8ba211ac76f20dd4867494d9b4a7f124731c44ba