Promoting the circularity of ceramic materials through cold sintering of aggregates from construction and demolition waste

Abstract

A ceramic composition containing 95 wt% of construction and demolition waste-like material was consolidated by cold sintering process at 200 °C using KOH water solutions as the liquid medium. The relative density of the samples reaches ∼90 % of the theoretical one for process conditions of 600 MPa and 60 min. A post-annealing process at 1100 °C of the as-cold sintered samples causes a slight increase in the relative density and of their mechanical strength compared with conventionally sintered samples at 1100 °C and increases the shape factor of the Weibull distribution, thus increasing the reliability of the component. It is shown that cold sintering of the material avoids its high pyroplasticity, providing low shrinkage and reducing internal defects in the ceramic. This work represents the first exploration of the viability of manufacturing ceramic tiles with high recycled content contributing to the transition to a greener world.