A visual investigation on chloride ingress into ceramic waste aggregate mortars having different water to cement ratios

In reinforced concrete structures, chloride ingress causes deleterious consequences due to corrosion of steel reinforcement. With no protective means, the service life of the structures is shortened proportionately to the rate of chloride ingress designated as a coefficient of chloride diffusion. Previous experimental study using the rapid chloride migration test has indicated that the use of ceramic waste aggregate (CWA) is effective in lowering the chloride diffusion coefficient of the 0.5 water to cement (W/C) ratio mortars and thus making mortars more durable. In this study, further experiments were conducted to seek visual evidences of the inhibiting of chloride ingress in the CWA mortars using a silver nitrate (AgNO 3 ) solution spray method and an electron probe microanalysis (EPMA) after 24 weeks submersion in 5.0 wt.% sodium chloride solution. The CWAs tested at this time were electrical porcelain insulator wastes from an electric power company, which were crushed and ground in a recycle plant. In particular, the test program was extended to investigate the CWA mortars at a wider range of W/C ratios, i.e. 0.4, 0.5, and 0.6. All the CWA mortars were also compared with their counterpart mortars made of typical river sand (RS). It is visually found that, at the W/C ratio of 0.4, 0.5, and 0.6, the CWA mortar is more effective in resisting chloride ingress (having lower coefficient of apparent chloride diffusion) than the RS mortar. Moreover, the compression test was carried out. It is worth noting that the CWA has no adverse effect on the compressive strength of mortars in relation to river sand.