Abstract
For reutilizing the cement sludge as a concrete waterproofer, the sludge was treated with stearic acid by chemical method. And we compared the performances of the new waterproofers with those of two others which have been used in demostic area. The particles of the new waterproofer are finer than those of standard sand but larger than those of cement. And the surfaces of the particles are coated with metallic soaps which have strong water repellency. Also the exess stearic acid and metallic soaps coated on the sludge react with the Ca++ or Al+++ when mixed with cement mortar. Therefore, the watertightness and the physical properties of the new waterproofers in cement mortar were superior to those of the others.
