evaluation of the relationships between the strength properties of hsc containing sf and gp at a low water-binder ratio

in this paper, the effect on the strength properties of high strength concrete (hsc) manufactured with silica fume (sf) and ground pumice (gp) is investigated. portland cement was replaced with sf, gp and combination of sf and gp up to 25%. 22 different concrete mixtures with these replacement ratios were produced by using 0.25 water-binder ratio. the ultrasound pulse velocity, compressive, splitting tensile and flexural strengths of these concretes were determined. the experimental results show that producing hsc is feasible with sf and gp. besides, the experimental results indicate that sf and sf in combination with gp can enhance both the short-term and the long-term properties of concrete, whereas gp needs a comparatively longer time to obtain a suitable effect. the results are also supported by scanning electron microscope analysis. the optimum replacement ratios of sf and gp are found to be 15% and 5% of cement, respectively. the relationships between ultrasound pulse velocity, compressive, splitting tensile and flexural strengths are investigated by considering the effects of sf and gp.