Bio-waste-based cement for sustainable civil engineering practice

Industrial byproducts are being increasingly used as raw materials in the cement clinker production. This can help to address the issue of huge amounts of eggshell waste that are discarded into the environment. This bio-waste has a trigonal-calcite structure and similar behaviour as limestone. In this study, cement clinker is synthesized at 1300 °C using eggshell waste in place of limestone. The raw materials are mechanically activated in a high-energy mill. The sintering kinetics are calculated using the results of differential thermal analysis. Mechanical activation modified the spatial distribution of Al, Si, Ca, and Fe, thereby improving the reactivity which in turn decreased the sintering temperature of the clinker. The study demonstrated that eggshell waste is a suitable replacement for limestone in the production of ordinary Portland cement.