生态再生混凝土抗硫酸盐侵蚀性能研究

Study on the resistance to sulphate erosion of recycled concrete

基于生态再生混凝土在实际工程中的应用要求,采用Ⅱ类再生粗骨料100%替代天然粗骨料,分别制备FA系列和S95矿粉系列生态再生混凝土,FA和S95矿粉的掺加量为30%,矿物掺合料掺量为30%,通过调整天然细骨料的用量来确定孔隙率的大小,对比分析W/C和孔隙率大小对生态再生混凝土的力学性能及抗SO42-盐侵蚀性能的影响规律。研究结果表明:减小W/C和降低孔隙率大小均能够提高生态再生混凝土的力学性能和抗SO42-盐侵蚀性能;在经过SO42-盐侵蚀干湿循环次数达到60次后,其抗压强度耐蚀系数(Kf)均≥87.2%,S95矿粉系列生态再生混凝土的抗SO42-盐侵蚀性能明显优于FA系列;当孔隙率相同时,提高W/C,能够明显地降低Kf;对于相同胶凝材料体系的再生生态混凝土,孔隙率为15%的混凝土耐蚀系数均≥94.2%,其抗硫酸盐侵蚀性能良好。

Based on the application requirements of ecologically recycled concrete in practical projects,100%of recycled coarse aggregate is used as a substitute for natural coarse aggregate,and FA series and S95 mineral powder series of ecologically recycled concrete are prepared separately.The admixture of FA and S95 fines is 30%.The content of mineral admixture is 30%.The porosity was determined by adjusting the amount of natural fine aggregate.The mechanical properties and anti-SO42--salt of ecologically recycled concrete were compared between W/C and porosity.Erosion performance of the law.The results show that reducing the W/C and decreasing the porosity can both improve the mechanical properties and the SO42-salt resistance of the ecologically recycled concrete.The compressive strength of the eco-recycled concrete after 60 cycles of the dry and wet cycle has reached 60 times.The corrosion resistance coefficient(Kf)is≥87.2%,and the SO42-salt erosion resistance of the S95 mineral powder series of ecologically recycled concrete is significantly better than that of the FA series.When the porosity is the same,increasing the W/C can significantly reduce Kf.For the same The regenerated ecological concrete of the cementitious material system has a corrosion resistance coefficient of≥94.2%for concrete with a porosity of 15%,and its sulfate resistance is good.