Durability of proprietary cementitious materials for use in wastewater transport systems

Several methods and materials, such as high performance coatings, fiber glass reinforced linings, special mortars, brick or ceramic linings, etc., are used to protect concrete from sulfuric acid attack in a sewage environment. Two proprietary high alumina cementitious lining materials, CC and SC, are recent additions to the list of protective materials used in the Arabian Gulf. This paper documents the findings of a laboratory study under accelerated conditions as well as a two-year field study of CC and SC in a wastewater lift station in Jubail, Saudi Arabia. In the laboratory investigations, 50 mm cube mortar specimens prepared using: (1) SC, (2) CC, (3) Type I + 8% silica fume cement, (4) Type I + 20% fly ash cement and (5) Type I cement were exposed to 2% sulfuric acid for 150 days. The laboratory specimens were tested for weight reduction, compressive strength, sulfate content, and alkalinity. In the field, the walls and ceiling of a wastewater manhole were coated using the proprietary lining materials, SC and CC, and were exposed to a normal sewage service environment. Performance of the liner materials was monitored for sulfate content and alkalinity after 6, 12 and 24 months of exposure. The analysis and evaluation test data generated from the accelerated laboratory study and the field study, which lasted for 24 months, showed that SC performed better than other materials tested in this investigation.