干湿循环作用下沙漠砂混凝土抗硫酸盐侵蚀性能研究

Research on the Performance of Desert Sand Concrete Under Dry-Wet Cycles with Sulfate Erosion

对干湿循环作用下硫酸盐侵蚀沙漠砂混凝土进行力学性能试验研究,采用质量损失率、抗压耐蚀系数、相对动弹性模量来表征沙漠砂混凝土硫酸盐-干湿循环作用下性能劣化。试验结果表明:随着干湿循环次数增加,沙漠砂混凝土质量损失率先减小后增大,抗压耐蚀系数和相对动弹性模量先增大后减小。干湿循环60次时,质量损失率达到最小值,抗压耐蚀系数和相对动弹性模量达到最大值。随着硫酸盐溶液浓度升高,抗压耐蚀系数和相对动弹性模量降低幅度增大,取代率为40%的沙漠砂混凝土抗压耐蚀系数和相对动弹性模量比普通混凝土高。以动弹性模量定义损伤度,相对峰值应力和峰值应变与损伤度呈指数关系,其相关系数均达到0.93以上。

In order to study the performance of desert sand concrete after sulfate attack,the mechanical properties of sulfate attacked desert sand concrete under the action of wet-dry cycles were tested.The mass loss rate,compressive corrosion resistance coefficient and dynamic elastic modulus were used to symbol the mechanical properties deterioration of desert sand concrete under the action of sulfate erosion and wet-dry cycles.Experimental results showed that with the increase of the number of dry-wet cycles,the mass loss rate of desert sand concrete decreased firstly and then increased.The compressive corrosion resistance coefficient and relative dynamic modulus of elasticity increased firstly and then decreased.When the number of wet-dry cycles was equal to 60,the mass loss rate of desert sand concrete reached the minimum,and the compressive corrosion resistance coefficient and relative dynamic modulus of elasticity arrived at maximum.The higher the sulfate solution concentration,the greater the decrease in compressive corrosion resistance coefficient and relative dynamic modulus.The compressive corrosion resistance coefficient and relative dynamic modulus of desert sand concrete with the desert sand replacement ratio of 40%were higher than that of ordinary concrete.Dynamic elastic modulus was used to define damage variable.The relative peak stress and peak strain were exponentially related to the damage variable,the correlation coefficients of which were all above 0.93.