Influences of carbonation on heavy metal diffusivity in cement hydrates

Abstract

Many studies on the effective utilization of industrial by-products such as blast furnace slag and fly ash have been carried out. There is a possibility of heavy metal leaching from concrete containing wastes. In order to promote the use of wastes as a concrete material, the environmental impact of concrete containing heavy metals must be appropriately evaluated. In this study, the mobility and adsorptivity of heavy metal ions were investigated using carbonated cement hydrates containing heavy metals with a diffusion test and an adsorption test. Copper, zinc and lead were used as heavy metals. As a result, it was found that the diffusivity of heavy metals in cement hydrates should be very low even if cement hydrates are carbonated. Lead ions were less adsorbed on carbonated cement hydrates than on non-carbonated cement hydrates although the value of pH in pore solution decreased.