摘要:
将再生高钛重矿渣粗、细骨料按50%、75%、100%的取代率取代高钛重矿渣粗、细骨料制备强度等级为C20、C25、C30的高钛重矿渣再生混凝土并测定其28 d强度,采用抗氯离子渗透试验、快速冻融试验、抗硫酸盐干湿循环侵蚀试验研究其耐久性能。试验结果表明:再生混凝土实测强度随再生骨料取代率的增大而减小,各个强度等级混凝土的实测强度均能达到设计强度,但强度富余小;再生混凝土DRCM值随骨料取代率及强度等级的提高而降低,最小及最大DRCM值分别为2.3×10-12 m2/s和3.3×10-12 m2/s,耐久性推荐水平分别为好和较好;再生混凝土抗冻性能随再生骨料取代率及强度等级的提高逐渐增强,但仅有再生骨料取代率为75%、100%的C25再生混凝土及取代率为100%的C30再生混凝土达到100次冻融循环的抗冻等级;30次硫酸盐干湿循环侵蚀对再生混凝土的强度影响很小,在同一强度等级下,再生混凝土抗硫酸盐侵蚀性能随再生骨料取代率的升高而减小,强度等级越小,减小幅度越大。
Abstract:
Replacing coarse and fine aggregates of high-titanium heavy slag with 50%,75%,and 100% replacement rates of coarse and fine aggregates of high-titanium heavy slag to prepare high-titanium heavy-slag recycled concrete with strength classes C20,C25,C30 was carried out,and the 28-day strength was measured.The durability of the samples was studied by resistance to chloride ion penetration test,rapid freeze-thaw test,and resistance to sulfate wet and dry cycle erosion test.The test results show that the measured strength of the recycled concrete decreases with increase of the replacement rate of the recycled aggregate,and the measured strength of each strength grade concrete can reach the design strength,but the strength margin is small.The DRCM value of the recycled concrete decreases with increase of the replacement rate and strength of the aggregate.The minimum and maximum DRCM values are 2.3×10-12 m2/s and 3.3×10-12 m2/s,respectively.The frost resistance of recycled concrete increases with gradual increase of the replacement rate of recycled bone and the strength grade,but only the C25 recycled concrete with 75% and 100% recycled aggregate and the C30 recycled concrete with 100% replacement reach the freeze-thaw rating of 100 freeze-thaw cycles.The effect of 30 sulfate dry-wet cycle erosions on the strength of recycled concrete is small.At the same strength level,the resistance to sulfate erosion of recycled concrete decreases with the increase of the replacement rate of recycled aggregate.The smaller the strength level,the smaller the decrease amplitude.
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