A comprehensive assessment of ceramic wastes in ultra-high-performance concrete

Abstract

Abstract This study investigates the utilization of ceramic waste from the ceramic manufacturing sector as a partial replacement for cement and fine aggregate in ultra-high-performance concrete (UHPC). Ceramic waste, ground into microparticles (555 m 2 /kg), replaced 10–50% of cement in 22 UHPC mixtures. One group used sand, and the other used ground ceramic waste as fine aggregate. Tests evaluated mechanical properties, consistency, durability, and microstructure. Results showed that SCWP and WCWP could replace up to 20% of cement, enhancing performance while maintaining desired mechanical and durability characteristics. The results showed that slump flow diameter decreased by increasing replacement ratios by SCWP and WCWP up to 50% of cement mass to 685 mm and 670 mm compared with the control mix, which had 770 mm for the first group and 634 mm and 615 mm in comparison to 713 mm for the control mix for the second group. Compressive strengths were increased to 171.3 MPa and 176.7 MPa, compared to 155 MPa for the control mix at 56 days in the first group. In the second group, compressive strengths reached 160.31 MPa and 165.33 MPa, compared to 143.15 MPa for the control mix at 56 days. All other mechanical properties, including compressive strength, are enhanced with cement replacement percentages of up to 20%. The study reveals that at 20% substitution of SCWP and WCWP, hardened UHPC properties such as tensile and flexural strength and modulus of elasticity significantly improved, reaching 21.31 MPa, 27.85 MPa, and 54.12 GPa for the first group and 19.97 MPa, 25.95 MPa, and 50.36 GPa for the second. Water permeability also decreased. The gradual increase in OPC replacement reduced compressive strength loss. The secondary C–S–H gel, formed from reactions with SCWP and WCWP, filled micropores and enhanced UHPC’s microstructure and matrix density.