Evaluation of novel copper-based antimicrobial admixtures for biocorrosion mitigation of cement paste

Abstract

Copper-based antimicrobial admixtures have been favoured for mitigating microbially induced concrete corrosion (MICC) owing to their practical bactericidal abilities. However, concerns regarding the leachability of hazardous components and the long-term efficacy of these admixtures have hindered their industrial application, with limited understanding of their comparative antimicrobial performance and mechanisms. In this work, three conventional copper compounds (copper sulphate, copper acetate, and copper oxide) and two newly synthesized copper-modified admixtures (copper-exchanged montmorillonite and copper-chelated chitosan) were evaluated and compared in terms of their impact on the properties, biocorrosion resistance, and environmental impact of cement paste. The findings revealed that the inclusion of copper-containing admixtures led to increased slump flow, extended setting time, improved compressive strength, lowered porosity, and reduced corrosion depth in the cement paste. Compared with copper sulphate and copper oxide, copper acetate exhibited superior engineering properties, antimicrobial performance, and reduced copper ion leaching. Cu-modified montmorillonite emerged as the most effective copper-based antimicrobial agent, considerably reducing the corrosion depth of cement paste by 32.8 % with the lowest copper leaching, suggesting its potential as a sustainable solution for antimicrobial concrete applications. In contrast, adding chitosan led to poor mechanical and adverse antimicrobial performance, indicating its limited potential as a carrier for synthesized antimicrobial agents.