Using nano-CaCO3 and ceramic tile waste to design low-carbon ultra high performance concrete

Abstract

Abstract China’s annual production of ceramic tiles inevitably produces a large amount of ceramic tile waste, which causes environmental and land occupation problems. Using a high-volume ceramic tile waste to fabricate ultra high performance concrete (UHPC) will reduce the workability and mechanical properties but increase the low-carbon properties. Motivated by such mechanical and low-carbon properties, this study introduced inexpensive, spherical, low-carbon nano-CaCO3 (NC) to improve the workability and mechanical properties of UHPC with a high volume of ceramic tile waste powder and aggregate (UHPCHCTWPA). The results of this study indicated that NC can improve the workability but shortened the setting times of UHPCHCTWPA. NC also significantly increases the mechanical properties including compressive strength, compressive work, flexural strength, fracture energy, and ratio of flexural strength to compressive strength. It is due to that NC enhances the hydration rate and hydration degree, and optimizes hydration product orientation, size, and distribution. Moreover, compared with UHPC, the UHPCHCTWPA with NC reduces energy intensity, CO2 emission, and cost by more than 20%. Therefore, adding NC can make UHPCHCTWPA with good workability, mechanical and low-carbon properties and can effectively and quickly utilize ceramic tile waste.