低温环境下含石灰石粉水泥基材料抗硫酸盐侵蚀性能研究OA北大核心CSTPCD

In order to improve sulfate resistance performance of cement-based materials containing limestone powder at low temperature,the sulfate resistance and mechanism of cement-based materials containing limestone powder mixed with different mineral admixtures were studied by using pulsed electrical field to accelerate sulfate erosion,observing the changes of specimen appearance and measuring the microscopic components of the corrosion material by XRD and FT-IR.The results indicate that the incorporation of mineral admixtures can enhance the sulfate resistance performance of cement-based materials containing limestone powder in low-temperature to some extent,and the inhibitory effect of combined mineral admixture is found to be more pronounced compared with single mineral admixture.However,the minimum content requirements of mineral admixtures should be met.It is suggested that,in the case of single mineral admixture,the mass proportion of fly ash or slag powder in cement-based materials should not be less than 30％and 50％,respectively.The sum of fly ash and slag powder content should be 50％～70％in the case of combined mineral admixture,and the mass ratio of fly ash and slag powder is 1.0∶1.5～1.0∶2.5.In addition,during thaumasite form of sulfate attack(TSA)of cement-based materials containing limestene powder,the diffraction peak of thaumasite is mainly formed by the rightward shift of ettringite diffraction peak,indicating that the formation of thaumasite is mainly formed by the transformation of ettringite.Therefore,the effective inhibition of formation of ettringite is the key point to inhibit TSA for cement-based materials containing limestone powder.