Aeration of Cement and Cement Mortar Paste through Colloidal Gas Aphrons

Abstract

Aeration of cement and cement mortars is a critical step in the manufacture of aerated concrete. Presently, metallic powders and foams are used for air entrainment. This paper explores a new method of air entrainment. Aerated concrete has been prepared in the laboratory with separate systems of cement-sand, cement-fly ash, and cement-GBFS (granulated blast furnace slag). Each system has been aerated with different volumes of colloidal gas aphrons (CGAs). CGAs are used as an aerating medium, and a kinetic generation model is studied using anionic, cationic, and nonionic surfactants. The paste density and air content have been measured for the green mass of mortar produced. The resulting aerated concrete after curing has been evaluated for its properties, e.g., porosity, dry density and, compressive strength. The microstructure of aerated concrete produced by the CGAs method of aeration has been studied using scanning electron microscope, which confirmed that the CGAs can create stable air voids in the cement mortar leading to its successful aeration. The method of manufacture of aerated concrete by the CGAs route of air entrainment has the potential for utilization of higher percentages of industrial wastes like fly ash and GBFS.