Ultra-high performance concrete prepared with ceramic polishing waste: Hydration, microstructure and mechanical property

This study aims to clarify the effects of ceramic polishing waste (CPW) on the hydration properties, micro-structure development and mechanical properties of ultra-high performance concrete (UHPC). In present work, CPW was used as an auxiliary cementitious material to replace cement(C), fly ash (FA) and silica fume (SF). Firstly, the pozzolanic activity of CPW was examined via Frattini test method. Then, the hydration kinetics of UHPC with CPW was characterized by isothermal calorimetry, low-field NMR and chemical shrinkage. The hydration product and microstructure of UHPC with CPW were also studied by XRD, TGA and SEM. Finally, the effect of CPW substitute on workability and mechanical properties of UHPC was investigated. Results showed that CPW performed excellent pozzolanic activity, and it could participate in the hydration reaction at the late age. When the replacement ratio of cement with CPW was less than 20%, the compressive strength of UHPC was slightly decreased in the early stage, however, the strength could be comparable to that of UHPC without CPW at 56 d. Besides, it is noteworthy that the compressive strength of all UHPC with CPW exceeded 120 MPa at 28 d. This paper developed a novel application scenario for CPW that would help alleviate the problem of tight supply of raw materials such as SF and FA.