Time Dependency on Chloride Diffusion of Ceramic Waste Aggregate Mortars Containing Ground Granulated Blast-Furnace Slag

Abstract

From our previous findings, the recycling of ceramic waste aggregate (CWA) in mortar has been proved an ecological means plus an excellent outcome against chloride ingress. The CWAs were electric porcelain insulator wastes supplied from an electric power company, which were crushed and ground to fine aggregate sizes. In this study, to further develop the CWA mortar as an eco-efficient, ground granulated blast-furnace slag (GGBS) was incorporated. The GGBS was utilized as a supplementary cementitious material (SCM) at three different replacement levels of 15, 30, and 45% by weight of cement. The time dependency of the GGBS on enhancing chloride resistance in the CWA mortars was experimentally assessed by using an electron probe microanalysis (EPMA). The tests were carried out on mortar samples after immersion in 5.0% NaCl solution for 24, 48, and 96 weeks. Another set of the mortar samples was exposed to a laboratory ambient condition for 24, 48, and 96 weeks and then followed with a carbonation test. The resistance to the chloride ingress of the CWA mortar becomes more effective in proportion to the replacement level of the GGBS. Meanwhile, the carbonation depth of the CWA mortar increases with increasing the GGBS. The relationship between the apparent chloride diffusion coefficient and the GGBS replacement level was shown along with the immersion time.

Characteristics of Chloride Diffusion and Pore Volume in Ceramic Waste Aggregate Mortar Containing GGBS

“…To enhance the chloride resistance of the CWA mortars, the authors have studied on the CWA mortars containing GGBS [19], [20]. In the previous study [19], the chloride ingress tests were performed on the CWA mortars, which have the water-to-binder ratio (W/B) of only 0.5, partially replaced with the GGBS at 15, 30, and 45% by mass. The GGBS significantly decreased the chloride ion penetration and the changing of the apparent chloride diffusion coefficients were relatively small along the immersion time up to 96 weeks.…”