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 Bridge Piers Concrete--Biodegradation--Texas Concrete Bridges Concrete Bridges--Texas--Foundations And Piers Foundations Piers (Supports)
• 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.
  
  
• Format:
  PDF
• Funding:
  DTRT07-G-0006
• Collection(s):
  University Transportation Centers US Transportation Collection
• Main Document Checksum:
  urn:sha-512:c391e134a1e617cd7542c421025650eaebec9b448de881338ed58bc24e9e9542ed1ea889441239ece694ffea8ba211ac76f20dd4867494d9b4a7f124731c44ba
• Download URL:
  https://rosap.ntl.bts.gov/view/dot/16891/dot_16891_DS1.pdf
• File Type:
  [PDF - 1.63 MB ]