Dolomite-based quarry-dust as a substitute for fly-ash geopolymers and cement pastes

摘要

The effects of the addition of dolomite-based quarry-dust (QD) waste material as a filler in CEM-I and FA based geopolymeric mixtures were studied. This study shows that unused QD may be integrated at high replacement rates (up to 40% by weight) in both CEM-I and FA-based systems, showing good and, in some cases, even significant improvement in their engineering properties. A significant increase in compressive strength was found for both CEM- and FA-based mixtures when gradually increasing the QD content. Two main mechanisms were suggested that may support this positive effect: the mechanical anchoring of the QD particles within the matrix, which was mainly found in the FA-based mixtures, due to the significant differences in their particle shape and morphology, and the enhancement of the hydration reaction in the presence of the QD particles mainly found in the CEM-based mixtures. Nevertheless, the vulnerability of these QD containing products to acidic conditions must be carefully considered. The ability to use quarry waste products as construction materials would not only reduce the costs and energy required for production processes but would also provide an efficient, green disposal path for quarry-dust waste, which currently poses an environmental problem without an alternative solution. (C) 2019 Published by Elsevier Ltd.