Microstructural study of carbonated cement-solidified synthetic heavy metal waste

Synthetic wastes have been widely employed to help elucidate the complex interactions between real wastes and hydraulic binders during solidification. In this work, a laboratory produced metal waste mixed with Portland cement and immediately carbonated it using an accelerated method. The microstructures of carbonated and non-carbonated control samples were distinct despite both being dominated by unusually large phenograins derived from the waste. In the carbonated sample waste phenograins remained unaltered, whereas cement grains were largely decalcified. As a consequence of decalcification, observable porosity was significantly reduced by the formation of precipitated carbonates.