Lab-to-Field Performance Evaluation of Antimicrobial Admixtures for Bio-corrosion Mitigation of Concrete

Microbial-induced concrete corrosion (MICC) poses a significant threat to the durability of sewer infrastructure, driven by sulfuric acid-producing bacteria under anaerobic-aerobic transitions. This study evaluates nine antimicrobial admixtures, including three conventional (e.g., sodium nitrite, copper nitrate) and six novel formulations (e.g., copper-exchanged zeolite, benzoate-intercalated LDHs), for their efficacy in mitigating MICC. Laboratory assessments of engineering properties (slump, setting time, compressive strength) of admixed concretes and their resistance to simulated microbial corrosion were complemented by a 12-month field test in an operational sewer. Multi-criteria decision analysis (TOPSIS) ranked admixtures, while correlation analysis validated laboratory results against field performance. Antimicrobial agents were categorized as dose-responsive or dose-limited, based on their dose-dependent efficacy and compatibility with concrete matrices. The results showed that concrete incorporating 0.5% DTAC-modified montmorillonite or 2.0% benzoate-intercalated LDHs emerged as top performers, reducing corrosion depth of concrete by up to 66% under aggressive sewer conditions while preserving structural integrity. Immobilizing copper ions via carriers (e.g., zeolite, montmorillonite) mitigated adverse effects on workability and strength, achieving higher TOPSIS scores than unmodified copper compounds. Critically, laboratory-simulated corrosion tests strongly correlated with field data (correlation coefficient: 0.87–1.00), confirming their reliability for rapid antimicrobial screening. This work establishes tailored antimicrobial admixtures as a promising solution to extend sewer infrastructure lifespan and validates accelerated lab testing as a predictive tool for real-world performance.