Investigating the influence of basalt as mineral admixture on hydration and microstructure formation mechanism of cement

Basalt powder is a by-product of basalt stone crushing plant. It is a big problem to propose utilization of these by-products from the aspects of disposal, environmental pollution and health hazards. In this paper, basalt is attempted to manufacture concrete as a new mineral admixture. Firstly, the chemical compositions and the pozzolan activity of the basalt were measured. Secondly, the cementitious paste with basalt powder was prepared and the normal consistency, setting time and the compressive strength were tested. Finally, the isothermal calorimetric measurement, X-ray diffraction (XRD) and Scanning Electron Microscopy (SEM) test were conducted to investigate the hydration process and microstructure formation of the basalt blended paste. sults show that the basalt has obvious potential pozzolan activities and can be used as a new mineral admixture. The basalt has retardation effect on the setting and hydration heat evolution process of cement. Besides, early age compressive strength development of the basalt blended paste was normally less than the pure cement paste, but the strength are close at later ages.