MgCl2，Na2SO4复合腐蚀与弯曲荷载作用对碳化混凝土的抗冻性的影响  

Effects of Composite Solution of MgCl_2,Na_2SO_4 and Flexural Stress on Freezing-Thawing Durability of Carbonized Concretes

作　　者：麻海燕[1] 燕坤 黄东升[1] 杨礼明[1] 

机构地区：[1]南京航空航天大学航空宇航学院,南京210016 [2]南京市园林规划设计院有限责任公司,南京210013

出　　处：《南京航空航天大学学报》2008年第2期250-254,共5页Journal of Nanjing University of Aeronautics & Astronautics

基　　金：国家自然科学基金(50178044)资助项目;江苏省自然科学前期预研基金(BK2005216)资助项目

摘　　要：在未加载与加载条件下,采用快冻法研究了快速碳化28 d后的粉煤灰混凝土(FAC)、大掺量矿物掺合料混凝土(HCMC)和绿色高耐久性混凝土(GHDC)在水和5%MgCl2+5%Na2SO4复合溶液中的抗冻性。结果表明,碳化FAC和碳化HCMC的抗冻性与冻融介质的化学成分存在密切的关系,氯盐、镁盐和硫酸盐腐蚀对碳化FAC的冻融破坏存在叠加效应;镁盐和硫酸盐腐蚀能够缓解NaCl对碳化HCMC的冻融破坏,而NaCl腐蚀则能加速镁盐和硫酸盐对碳化HCMC的冻融破坏作用;NaCl的冰点降低作用能大大缓解碳化GHDC在腐蚀溶液中的冻融破坏,即使在镁盐和硫酸盐溶液中混有NaCl成分,也能够明显地提高碳化GHDC的抗冻性。进一步研究还表明,在(MgCl2+Na2SO4)复合溶液的冻融条件下,碳化显著降低了FAC和HCMC的耐久性,施加弯曲荷载使其耐久性进一步劣化,但GHDC的耐久性则不受碳化作用和外部弯曲荷载的影响。因此,GHDC即使发生了严重的碳化,在(MgCl2+Na2SO4)复合溶液、弯曲荷载和冻融循环及其多因素耦合作用下仍然具有非常高的耐久性。By using the method for accelerated freezing-thawing, the freezing-thawing durability of carbonized fly ash concrete （FAC）, concrete with high content mineral admixture （HCMC） and green high durable concrete （GHDC） subjected to water and the composite solution （5%MgC12＋5%Na2SO4） with and without loading are studied. Results show that the freezing-thawing durability of carbonized FAC and carbonized HCMC has a close relationship with the chemical composition of freeze-thaw medium. There is a superposed effect of chloride, magnesium and sulfate attack. Magnesium and sulfate can easily damage carbonized HCMC in NaC1 solution, but NaC1 solution can accelerate the damage of carbonized HCMC subjected to magnesium sulfate solution. NaC1 can decrease the freezing point, it is beneficial to freezing-thawing durability of carbonized GHDC though subjected to magnesium sulfate solution. Further studies show that the freezing-thawing durability of FAC and HCMC reduces in composite solution （MgC12＋Na2SO4） due to the carbonation. It is worse under the effect of flexural stress. But they have no effect on GHDC. So although GHDC is carbonized badly, it also has a high freezing-thaw- ing durability subjected to the composite solution （MgC12＋Na2SO4）, flexural stress, freezing-thawing cycles and their combination.

关 键 词：混凝土 碳化作用 抗冻性 复合溶液 弯曲荷载 

分 类 号：TP183[自动化与计算机技术—控制理论与控制工程]