硫酸盐冻融对自密实再生粗骨料混凝土力学性能的影响  

Effect of Sulfate Freeze-Thaw on Mechanical Properties of Self-Compacting Recycled Coarse Aggregate Concrete

作　　者：侯玉飞[1] 郑传磊 赵亚娣 金宝宏[2] HOU Yufei;ZHENG Chuanlei;ZHAO Yadi;JIN Baohong(Xinhua College,Ningxia University,Yinchuan 750021,China;School of Civil and Hydraulic Engineering,Ningxia University,Yinchuan 750021,China)

机构地区：[1]宁夏大学新华学院,银川750021 [2]宁夏大学土木与水利工程学院,银川750021

出　　处：《工业建筑》2023年第7期189-198,6,共11页Industrial Construction

基　　金：国家自然科学基金项目(51968060);宁夏大学新华学院重点学科建设项目(ZDXK-2019-01);宁夏高等学校科研项目(NGY2020103)。

摘　　要：采用快速冻融循环法研究再生粗骨料(RCA)替代率、冻融环境及冻融循环次数对自密实再生粗骨料混凝土(SCRCAC)力学性能的影响。结果表明:RCA替代率相同时,清水冻融环境中SCRCAC经历125次冻融循环后的抗压强度、劈拉强度及单轴抗压强度损失率最小,5%质量分数的MgSO4溶液冻融环境中为最大。冻融试验初期硫酸盐可抑制冻融损伤。冻融试验后期,不同冻融环境及RCA取代率下再生粗骨料混凝土与普通混凝土的抗压强度与冻融循环次数的关系曲线逐渐呈现分离。基于此,提出了劈裂抗拉及单轴抗压强度与抗压强度之间的新关系式,该模型能较好地预测RCASCC经硫酸盐冻融后的损伤劣化规律。建立的强度预测模型经游程检验表明模型精度较高。灰熵关联分析表明:清水、5%质量分数的Na2SO4溶液及5%质量分数的Na2SO4与5%质量分数的MgSO4的混合盐溶液冻融环境中冻融循环次数对抗压强度及劈拉强度的影响大于RCA取代率;而与5%质量分数的MgSO4溶液中情况相反;清水环境中冻融循环次数对单轴抗压强度的影响大于RCA取代率。The effect of recycled coarse aggregate(RCA)replacement ratios,freeze-thaw environments and freeze-thaw cycles on the mechanical properties of self-compacting recycled coarse aggregate concrete(SCRCAC)were studied by rapid freeze-thaw cycle method.The results showed that when the RCA replacement ratios were the same,the compressive strength,splitting tensile strength and uniaxial compressive strength loss ratio of SCRCAC after being subjected to 125 freeze-thaw cycles were the smallest in the freeze-thaw environment of clear water,and the maximum in the 5%mass fraction MgSO 4 solution freeze-thaw environment.Sulfate could inhibit freeze-thaw damage at the initial stage of freeze-thaw.At the late stage of freeze-thaw,the relation curves of compressive strength and freeze-thaw cycles of SCRCAC gradually spearated from that curves of ordinary concrete in different freeze-thaw environments and RCA replacement ratios.Based on that,a new relation between the splitting tensile force and the uniaxial compressive force was presented,better predicted the damage and deterioration law of SCRCAC after freeze-thawing of sulfate.The established strength prediction model showed that the model had high accuracy.Grey entropy correlation analysis showed that the effect of freeze-thaw cycles on compressive strength and splitting tensile strength was greater than that of RCA replacement ratios in the freeze-thaw environment of clear water,in the solution of 5%mass fraction of Na 2SO 4,and in the solution of 5%mass fraction of Na 2SO 4 and 5%mass fraction of MgSO 4.However,contrary to the situation of the solution of 5%mass fraction of MgSO 4.The effect of freeze-thaw cycles on the uniaxial compressive strength was larger than the RCA replacement ratio in clear water.

关 键 词：再生粗骨料自密实混凝土 换算关系 冻融损伤模型 强度预测模型 游程检验 灰熵关联分析 

分 类 号：TU528[建筑科学—建筑技术科学]