Simulation Study of Three-Stage Corrosion of Portland, Aluminate, and Alkali-Activated Cementitious Materials in Sewers

To simulate the service behavior of new-made concrete pipelines in a sewage environment, the corrosion of different mortars in three stages of abiotic neutralization, neutral, and acidophilic bacteria action was studied. The alkali-activated mortars showed a more intact appearance, lower loss rates of mass and strength, and less biofilm attachment, but greater neutralization depth compared with ordinary portland cement mortar (OPCm) after corrosion. Based on the establishment of a two-stage linear model of corrosion initial and progressive periods, the predicted service life of alkali-activated fly ash mortar is approximately 2.5 times that of OPCm, and longer than that of calcium aluminate cement mortar.