Calcium aluminate cement linings for cost-effective sewers

In South Africa, the traditional solution for large diameter sewers a concrete pipe made with calcareous aggregate a sacrificial layer on the inside. When self-cleansing velocities occur, corrosion potential is mild and this approach is adequate. However, when hydraulic conditions are unfavourable, the corrosion potential increases and this solution may prove inadequate. Rapid urbanization and limited resources in South Africa, where less than half the population have adequate sanitation, call for alternative solutions when potential for corrosion is high. Based on information from various research institutions and an experimental section of live sewer, with which the author has been personally involved, the concept of a host pipe made of ordinary Portland cement concrete, with a sacrificial layer comprising calcium aluminate cement concrete, was successfully developed and launched in the marketplace. Aspects of this cost-effective development and the supporting research are presented and recommendations for its application made.