高性能混凝土在氯盐侵蚀和冻融循环作用下的耐久性分析  

Durability Analysis of High-Performance Concrete Under Chloride Salt Erosion and Freeze-Thaw Cycles

作　　者：冯博[1] 刘青[1] 钱永久[1] FENG Bo;LIU Qing;QIAN Yongjiu(School of Civil Engineering,Southwest Jiaotong University,Chengdu 610031,China)

机构地区：[1]西南交通大学土木工程学院,四川成都610031

出　　处：《西南交通大学学报》2023年第5期1083-1089,共7页Journal of Southwest Jiaotong University

基　　金：国家自然科学基金(51778532)。

摘　　要：为研究海洋环境下高性能混凝土桥梁的耐久性,基于混凝土室内快速冻融试验,对高性能混凝土进行氯盐侵蚀与冻融循环耦合作用下的耐久性试验,分析混凝土在不同水胶比、粉煤灰掺量和含气量时的质量损失率和相对动弹性模量;并根据试验分析结果建立氯盐侵蚀与冻融循环耦合作用下的高性能混凝土质量预测衰减模型.结果表明:水胶比对高性能混凝土的抗盐冻性能影响显著,混凝土抗盐冻性能随着水胶比增大而降低,建议水胶比不宜大于0.45;粉煤灰的加入会降低混凝土的抗盐冻性能,掺量较高时其抗盐冻性能难以达到满足要求,粉煤灰掺量不宜高于30%;随着含气量增加,混凝土抗盐冻性能呈现先提升后降低的变化规律,建议有考虑抗盐冻要求的混凝土其含气量在4.5%~5.5%内选取.In order to study the durability of high-performance concrete(HPC)bridges in the marine environment,based on the rapid indoor freeze-thaw test of concrete,the durability of HPC under the coupled action of chloride salt erosion and freeze-thaw cycles was tested,and the mass loss rate and relative dynamic elastic modulus of concrete under different water-binder ratios,fly ash contents,and air contents were analyzed.According to the test analysis results,a quality prediction attenuation model of HPC under the coupled action of chloride salt erosion and freeze-thaw cycles was established.The results show that the water-binder ratio has a great influence on the salt-freezing resistance of HPC.The salt-freezing resistance of concrete decreases with the increase in the water-binder ratio,and it is suggested that the water-binder ratio should not be greater than 0.45;the addition of fly ash will reduce the salt-freezing resistance of concrete,and the salt-freezing resistance can hardly meet the requirements when the fly ash content is high.Therefore,the fly ash content should not be higher than 30%;as air content increases,the salt-freezing resistance of concrete first increases and then decreases.The air content of concrete considering the salt-freezing resistance requirements is recommended to be selected within the range of 4.5%–5.5%.

关 键 词：高性能混凝土 氯盐侵蚀 冻融循环 耐久性 

分 类 号：U444[建筑科学—桥梁与隧道工程]