Study on the Calcinations of Recycled Cement Clinker Using Waste Concrete and Waste Clay Brick

摘要

Utilizing construction waste, mainly waste concrete, to produce recycled cement, provides possibility for realizing the closed circulation between concrete and cement, which is an effective way for sustainable development of cement and concrete industry. Waste clay brick (WCB) and its surface-coated waste mortar are inevitably introduced into the raw meals while waste concrete is used in cement production. So on the basis of the composition characteristics of construction waste, considering of optimizing the performance of recycled cement and improving the adaptability of recycled cement to complex raw material, it's necessary to study the effect of raw meal mixing waste concrete and WCB on sintering process and property of recycled cement clinker. Mixing waste concrete and WCB in three different proportions, the burnability of raw meal, clinker mineral composition, clinker mineral morphology and hydration characteristics of recycled cement have been studied in this paper. The results indicate, the presence of WCB is beneficial for the generation and development of silicate minerals;;with increasing proportion of WCB, the content of f-CaO in recycled cement clinker rises, the structure of C-S-H gel from hydration product presents higher densification and the compression strength of 3d and 28d curing period are enhanced.