Preliminary Investigation into the Effects of Carbonation on Cement-Solidified Hazardous Wastes

Abstract

This paper reports results from a preliminary investigation into the effects of carbonation on a cement-solidified waste material. The waste, which is a commercially blended product, was solidified using different amounts of ordinary Portland cement (OPC) and cured in three different environments: nitrogen, air, and carbon dioxide. After 28 days, the samples were investigated for leachate metals fixation, strength, and microstructural development. Carbonation was found to play an important role in “accelerating” the apparent hydration of binder within the solidified waste forms. Carbonated solidified products were characterized by enhanced calcite contents, higher strength values, and a significant reduction in leachable metals extracted compared to air-cured samples. Samples cured under a nitrogen atmosphere showed significant retardation of hydration, resulting in low strength values but improved fixation of leachable metals.