Evaluation of the internal high alumina cement mortar lining of ductile cast iron pipes used in sewage transportation

摘要

High alumina cement has been used to line the interior of ductile cast iron pipes intended for sewage transportation. Defects occurring in the production line include waves, ripples, knots, strip cracks, milky layers, crack network, non uniform thickness, breakage and roughness. The effect of the grain size of sand, the water/cement ratio, the sand/cement ratio and the percent citric acid added as a retar-der and a plasticizer, on the different properties of the lining mortar. The optimum conditions obtained were used to line 900 mm diameter C.I. pipes. An appreciable reduction of defects was observed.