随着优质粉煤灰的短缺,磨细石灰石粉取代粉煤灰逐步广泛应用在混凝土生产当中,本文以磨细石灰石粉作为变量,研究磨细石灰石粉对高性能混凝土流变性能、力学性能、耐久性的影响及作用机理.试验结果表明:随磨细石灰石粉掺量增加,混凝土坍落度、扩展度呈先增大后降低趋势,倒坍落度筒流空时间呈先降低后增大趋势,混凝土抗压强度及抗压强度比在3d、7d程增加趋势,在28d、56d呈降低趋势,混凝土电通量呈先降低后增加趋势.磨细石灰石粉对混凝土在水泥水化时起到微晶核效应,对早龄期水化速率作用明显,综合考虑混凝土拌合物流变性能、力学性能和耐久性能,磨细石灰石粉比表面积最佳取代量为15%.
With the shortage of high-quality fly ash,ground limestone powder has gradually been widely used in concrete production instead of fly ash.In this paper,the influence of ground limestone powder on rheological properties,mechanical properties,durability and mechanism of high-performance concrete with different variables of ground limestone powder were studied.The test results show that the slump and expansion of concrete first increase and then decrease,the flow empty time of the slump first decreases and then increases.The compressive strength and the ratio of compressive strength of concrete increase at 3d and 7d,and decrease at 28d and 56d.The electric flux of concrete first de-creases and then increases with the increase of the content of ground limestone powder.The ground limestone powder plays a microcrystalline nucleation effect during cement hydration in concrete,and has an obvious effect on the hydration rate at early age.The optimum replacement of ground limestone powder is 15%,is considered that the variable flow properties of concrete mixing,mechanical and dura-bility of concrete.