Analysis of a Composite Admixture Based on Ready-Mixed Concrete Waste Residuals

Abstract

Reasonable treatment and utilization of waste residuals discharged during the production of ready-mixed concrete is an important problem in the cement industry. In this study, a composite admixture was prepared by using ready-mixed concrete waste residuals, furnace slag, and water granulated slag. The grinding characteristics of such material were investigated. Moreover, the effect of such admixture on cement hydration and pore structure was analyzed by X-ray diffraction, thermogravimetric-differential scanning calorimetry, scanning electron microcopy and mercury intrusion porosimetry. As shown by the results: The grinding characteristics of the waste residuals can be improved significantly by mixing them with furnace slag and water granulated slag. Furthermore, the composite admixture does not change the composition of hydration products; rather it contributes to refine the pore structure of the matrix, thus improving the mechanical properties of these cement-based materials.