Laboratory simulation of the process of formation of sulphuric acid (H2SO4) on the non-submerged walls of concrete sewer pipes, and sub- sequent attack of products of cement hydration, has proved to be a challenging task over the years. This, coupled with scarce facilities for in-situ measurements, has generally contributed to the lack of a more comprehensive theory around durable cementitious materials that can withstand exposure to biogenic H2SO4 in a range of sewer environments. This paper focusses on the performance of different cementitious materials exposed in a ‘live’ experimental sewer in South Africa. The cementitious materials under review comprise those made with Portland cement and calcium aluminate cement. Results indicate that cements with high contents of aluminates perform better than silicate based cements when subjected to biogenic H2SO4 attack. Inevitably, use of aluminate-rich cements forms part of the solution in the development of durable cementitious linings for concrete sewer pipe applications.
University of Cape Town