Modelling the life-cycle of concrete gravity sewers subject to microbial corrosion

Long term deterioration of concrete sewer infrastructure costs the wastewater industry billions of dollars per year globally raising serious questions about how best to prioritize remedial and replacement work in order to maintain the sustainability of wastewater infrastructure. It follows that predicting the time to failure of existing reinforced concrete sewer systems is an important issue for wastewater utilities. A recently completed 6 year field trial examined the corrosion behavior of new and aged sewer pipe in Australian gravity sewers. The work shed light on the corrosion process timeline and the impact of the local sewer environment on the rate of corrosion experienced by concrete sewer mains. A service life prediction model for concrete sewer pipe which has been developed is discussed as well as methods for prolonging concrete sewer pipe service life.