再生混凝土抗硫酸盐侵蚀机理及可靠性分析

Mechanism and Reliability Analysis of Sulfate Resistance of Recycled Concrete

通过不同质量掺量的再生粗骨料(0%、30%和50%)和再生细骨料(0%和15%)来制备再生骨料混凝土(RAC),研究硫酸盐干湿循环试验中RAC质量和相对动弹性模量的劣化规律,并评判不同掺量下RAC抗硫酸盐侵蚀的能力。结果表明:随硫酸盐干湿循环次数的增加,相对动弹性模量先增大后减小,质量损失率则先下降后上升;干湿循环80次时,再生粗骨料混凝土的相对动弹性模量最大损失达60%,质量最多增长0.43%。此外,利用一元Winner分布建立可靠度模型,对硫酸盐干湿循环下RAC的演变规律进行评判,并结合扫描电镜(SEM)试验对侵蚀后的RAC微观形貌进行分析。

Recycled aggregate concrete(RAC) was prepared by different mass admixture of recycled coarse aggregate(0%, 30% and 50%) and recycled fine aggregate(0% and 15%). The deterioration law of RAC mass and relative dynamic elastic modulus in sulfate dry-wet cycle test was studied. The sulfate resistance of RAC under different admixture was evaluated. The results show that with the increase of dry-wet cycles of sulfate, the relative dynamic elastic modulus increases first and then decreases, and the mass loss rate decreases first and then increases. The maximum relative dynamic elastic modulus loss of recycled coarse aggregate concrete reaches 60%, and the maximum mass increase is 0.43%, after 80 times of dry-wet cycles. In addition, the reliability model was established by Winner distribution. The evolution of RAC was evaluated under sulfate dry-wet cycle, and the morphology of RAC after erosion was analyzed by scanning electron microscopy(SEM).