MICROBIAL INDUCED ACID CORROSION FROM A FIELD PERSPECTIVE – ADVANCES IN PROCESS UNDERSTANDING AND CONSTRUCTION MATERIAL DEVELOPMENT

Microbial induced acid corrosion is accounted for ~40 % of the degradation of subsurface wastewater infrastructure globally. While fundamental process understanding has increased significantly within the last decades, to date no sustainable building material exists, which meets the long-term requirements in such aggressive and corrosive environments. This work describes a novel model based on field studies, conducted in various Austrian sewer networks, intertwining biological, mineralogical and hydro-chemical factors. Additionally, an extensive field testing campaign over the duration of 18 months, conducted on different geopolymer concretes (GPC), particularly designed for the latter environments will be presented. Innovative GPCs were tested regarding their microstructural behavior, microbial accessibility and hydro-chemical alterations over time and compared to commercially produced cement based products, including OPC and CAC concretes. Additionally, the system specific environmental parameters, such as relevant gas concentrations (H2S, CO2, CH4), relative humidity and temperature were constantly monitored.