Speaker
Description
Concrete, protective coatings, and other construction materials deteriorate under biologically induced corrosive conditions commonly found in sewer systems. Understanding "corrosivity"—the severity of corrosion in a given environment—is essential for selecting appropriate materials, designing mitigation strategies, and estimating service life and lifecycle costs.
This study focuses on sewer-related corrosion of concrete infrastructure, including large-diameter pipes, access chambers, and wet wells. Degradation is primarily driven by microbial activity that produces sulphuric acid under specific environmental conditions.
A quantitative classification of sewer gas-phase corrosivity was developed using field data from ordinary Portland cement (OPC) assets in service for 17 to 81 years across Australian utilities. The classification was based on the relative depth of corrosion observed as a function of measured environmental parameters—specifically H₂S, CO₂, temperature, and relative humidity. These environmental conditions were used as surrogate indicators of corrosivity.
To validate the classification and assess its application to material selection, a range of commercially available materials—including calcium aluminate and geopolymer cement-based systems—were installed in sewers with different corrosivity classifications. Comparative observations across these environments demonstrated meaningful differences in material performance, confirming the classification’s practical relevance.
The findings show that environmental conditions can be effectively used to predict relative corrosivity in sewer networks, and that material performance varies significantly with exposure severity. The proposed classification offers engineers and asset managers a robust tool for aligning material selection with environmental conditions, improving durability, optimising lifecycle costs, and supporting resilient wastewater infrastructure.
Affiliations
- The University of Sydney, Sydney, NSW, 2006, Australia
- The Water Services Association of Australia, Melbourne, Victoria, 3008, Australia
| Title | A Framework for Classifying Sewer Gas-Phase Corrosivity Based on Material Response |
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| Keywords | corrosivity, sewer infrastructure, concrete durability, protective coatings and material degradation |