Influence of Portland blast-furnace slag cement and air-entraining and high range water-reducing admixture on some properties of concrete incorporating sludge

Abstract

Authors have been studying for several years as for the effective utilization of sludge water containing cement and fine particles of aggregate. Nowadays, JIS A 5308 permits the usage under 3 percent as solids of sludge for the unit content of cement of new concrete. This study, in order to utilize the larger quantity of sludge water than that now allowed in the mixing plants, is to obtain the basical data on the properties of fresh concrete and of hardened concrete. Especially, the influence of portland blast-furnace slag cement and air-entraining and high range water-reducing admixture (SP) has been discussed experimentally on the view points of slump, bleeding, compressive strength and drying shrinkage. From the results of this study it was clarified that a good quality concrete could be obtained regardless of the kind of cement and admixture, even though the sludge mass of 9% of cement content and the sludge age of 3 days, provided that setting retarder was used adequately.