碳化对CO_(2)强化再生骨料混凝土抗氯离子渗透性能的影响

Influence of Carbonation on Chloride Ion Penetration Resistance of CO_(2)Modified Recycled Aggregate Concrete

本工作以再生粗骨料(RCA)替代率为变量,采用CO_(2)对RCA进行强化处理,通过快速碳化试验和氯离子快速迁移试验(RCM法),研究了碳化对CO_(2)强化再生骨料混凝土(CRAC)抗氯离子渗透性能的影响。结果表明:当RCA替代率由0%增至100%时,RCA未强化的再生骨料混凝土(RAC)、碳化7 d后的RAC(C-RAC)、CRAC及碳化7 d后的CRAC(C-CRAC)的抗氯离子渗透性能的降幅分别为73.0%、90.8%、53.4%和80.8%。相较于RAC,当RCA替代率分别为50%、75%和100%时,CRAC的抗氯离子渗透性能分别提高了13.8%、16.6%和11.3%。当RCA替代率分别为0%、50%、75%和100%时,C-RAC的抗氯离子渗透性能相较于RAC分别提高了15.5%、23.6%、19.8%和6.8%;当RCA替代率分别为50%、75%和100%时,C-CRAC的抗氯离子渗透性能相较于CRAC分别提高了16.5%、9.6%和0.4%。CRAC碳化后,其对提高抗氯离子渗透性能的效果要优于仅对RCA或RAC进行碳化,当RCA替代率分别为50%、75%和100%时,C-CRAC的抗氯离子渗透性能相较于RAC分别提高了28.0%、24.6%和11.6%。

In this paper,the replacement rate of recycled coarse aggregate(RCA)was used as a variable,and CO_(2)was used to modify the RCA.Using the rapid carbonization test and the rapid chloride ion migration test(RCM method),the effect of carbonation on chloride ion penetration resistance of CO_(2)-modified recycled aggregate concrete(CRAC)was studied.The results showed that when the RCA replacement rate increased from 0%to 100%,the reductions of chloride ion penetration resistance of RCA unmodified recycled aggregate concrete(RAC),RAC after 7 days of carbonation(C-RAC),CRAC,and CRAC after 7 days of carbonation(C-CRAC)were 73.0%,90.8%,53.4%,and 80.8%,respectively.Compared with RAC,when the RCA replacement rates were 50%,75%,and 100%,the chloride ion permeation resistance of CRAC increased by 13.8%,16.6%,and 11.3%,respectively.Compared with RAC,when the RCA replacement rates were 0%,50%,75%,and 100%,the chloride ion permeation resistance of C-RAC increased by 15.5%,23.6%,19.8%,and 6.8%.Compared with CRAC,when the RCA replacement rates were 50%,75%,and 100%,the chloride ion permeation resistance of C-CRAC increased by 16.5%,9.6%,and 0.4%,respectively.After carbonation of CRAC,its effect on improving the resistance to chloride ion penetration was better than carbonation of RCA or RAC alone.When the RCA replacement rates were 50%,75%,and 100%,compared with RAC,the resistance to chloride ion penetration of C-CRAC increased by 28.0%,24.6%,and 11.6%,respectively.