Effectiveness of admixtures, surface treatments and antimicrobial compounds against biogenic sulfuric acid corrosion of concrete

In situ failure of laboratory tested coatings against biogenic sulfuric acid (BSA) corrosion of concrete in sewers has lead to new approaches that affect microbial activity. This paper reports on the performance of concrete surfaces containing antimicrobial polymer fibers or metal-zeolites in preventing BSA corrosion. Additionally, the effectiveness of commercial surface treatments and admixtures was measured by means of accelerated chemical exposure and microbiological simulation tests. The biocidal effect of antimicrobial additives was quantified by means of incubation tests on mortar specimens. The presence of antimicrobial compounds resulted in a 3-12-fold decrease of the bacterial activity, as observed from ATP measurements. The largest deterioration from the accelerated tests was noticed for a cementitious coating. The antimicrobial and silicates admixtures did not result in a protective effect towards degradation under the given test conditions. The best protection was obtained with a polyurea lining and an epoxy coating. No loss of coating integrity could be observed after 8 and 10 cycles of microbiological and chemical testing, respectively. (C) 2008 Elsevier Ltd. All rights reserved.