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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.

The copper-plated steel fiber has the characteristics of good electrical, mechanical and high conductivity, and the ceramic waste powders has the advantages of pozzolanic internal curing and low carbon properties. It is easy to form a good andchemically stable strengthening, toughening and conductive network by synergistic action. Therefore, the piezoresistivity properties of copper-plated steel fiber content and loading conditions on copper-plated steel reinforced fiber ultra high performance concrete with ceramic waste powders were studied by using uniform sieving method. The research shows that the copper-plated steel fiber can improve the piezoresistivity of ultra high performance concrete with ceramic tile waste powders with different content of copper-plated steel fibers under different load amplitudes and different loading rates. Compared with plain samples, the fractional change in resistivity and stress/strain sensitivity of 2.50 vol% content of copper-plated steel fibers reinforced ultra high performance concrete with ceramic waste powders are increased by 650.0%, 614.3% and 1 223.0%, respectively. Moreover, it can be seen that the loading amplitude has the greatest influence on the piezoresistivity performance among copper-plated steel fibers and loading rates. The stress-electricity model shows that the relationship between the fractional change in resistivity and stress/strain sensitivity of ultra high performance concrete with ceramic waste powders is exponential function under cyclic load, and the fitting degree is above 0.90. Therefore, the stress/strain monitoring of concrete structures can be realized by testing the resistivity of copper-plated steel fiber reinforced ultra high performance concrete with ceramic waste powders. [ABSTRACT FROM AUTHOR]