Title: Comparison of Chemical and Biogenic Acid Attack on Concrete

Author(s): Ali Riza Erbektas, O. Burkan Isgor, and W. Jason Weiss

Publication: Materials Journal

Volume: 117

Issue: 1

Appears on pages(s): 255-264

Keywords: acid attack; bacterial corrosion; biogenic sulfuric acid; chemical attack; deterioration; durability; microbially induced corrosion of concrete (MICC)

DOI: 10.14359/51720293

Date: 1/1/2020

Abstract:
This paper compares biogenic and chemical acid attack for assessing the final stage of microbially induced corrosion of concrete (MICC). Paste specimens were exposed to either biogenic or sulfuric acid solutions. The solutions had an initial pH of 2. Maintaining the pH of the chemical acid solution in the desired range was highly challenging. The pH of biogenic acid solution remained consistent for a longer time. Calcium leaching measurements showed that biofilm on the surface of specimens exposed to biogenic acidification restricted excessive leaching of calcium from the samples. X-ray fluorescence (XRF) results showed that biogenic acid attack caused higher changes in the chemical composition of the specimens. Flexural strength tests did not show a significant difference between the chemical and biogenic acid attack; however, this could be attributed to the short test duration.