Combined Potential of Quarry Waste Fines and Eggshells for the Hydrothermal Synthesis of Tobermorite at Varying Cement Content

Abstract

Quarry waste fines and eggshells are unavoidable wastes which relentlessly contribute to environmental loads and pollution. Although many studies have suggested various methods for recycling, these wastes remain underutilized due to some technical constraints. In addition, no study has yet explored the possibility of combining quarry waste fines (QWF) and eggshell powder (ESP) for tobermorite synthesis. Tobermorite is the main component which primarily provides strength to autoclaved aerated concrete products. With this in mind, this study seeks to evaluate the potential of QWF-ESP mix at 10%, 15%, and 20% amounts of cement, respectively. The XRF, XRD, and TGA–DTA techniques were used to characterize the waste materials, while physical and mechanical property tests and XRD analysis were performed on the autoclaved samples. It was found that QWF contains 53.77% SiO2 and ESP contains 97.8% CaO which are key components for tobermorite synthesis. This study also revealed that the mixture with only 10% cement has the highest compressive strength among the QWF-ESP samples. Furthermore, the formation of tobermorite in the samples was confirmed through XRD analysis. Hence, the hydrothermal curing of QWF-ESP can be further developed to produce functional tobermorite-bearing materials.