Characteristics of chloride ingress into mortars containing ceramic waste aggregate

The characteristics of chloride ingress into mortar containing ceramic waste aggregate (CWA) were investigated by using an electron probe micro-analyzer. The CWA was produced from electric porcelain insulator wastes via the processes of crushing and grinding. The CWA mortar in which entire fine aggregate was replaced with the CWA was studied in comparison with typical river sand (RS) mortar. For both mortars, the water to cement ratio (W/C) was varied at 0.4, 0.5, and 0.6. The chloride ingress was introduced to the mortars through the immersion in a 5.0 wt% sodium chloride solution for 24, 48, and 96 weeks. It is clearly evident that the CWA mortar had smaller chloride penetration than the RS mortar. Furthermore, to manifest how the CWA reduced the chloride ingress, either the pore size distribution of the CWA and the RS mortars or the zeta potential on the CWA and the RS particles in a high-alkaline solution simulating the pore solution was conducted. The CWA mortars had much lower pore volume than the RS mortars, whereas the zeta potential of both particles was not markedly different. It was thus indicated that the pore size distribution is of greater influence than the zeta potential.