复合盐侵-冻融环境下混凝土的应力-应变关系试验研究  

Experimental study on stress-strain relationship of concrete under multi-salt soaking and freezing-thawing

作　　者：韩霄羽 姚贤华 管俊峰 钱国双 

机构地区：[1]华北水利水电大学土木与交通学院,河南郑州450011

出　　处：《混凝土》2017年第10期20-23,28,共5页Concrete

基　　金：国家自然科学基金面上项目(51779095);国家自然科学基金青年基金(51209094);郑州市科技攻关项目(153PKJGG111)

摘　　要：对混凝土在3.5%、10.5%、17.5%复合盐(NaCl、Na_2SO_4、NaHCO_3、Na_2CO_3)溶液的侵蚀作用下,研究了在复合盐侵蚀和冻融循环作用下C30混凝土的应力-应变关系的变化规律,对6组42个尺寸为100 mm×100 mm×100 mm的混凝土立方体试件进行了冻融循环,并利用SEM扫描电镜观察冻融作用后混凝土内部显微结构的变化。试验结果表明:(1)复合盐溶液侵蚀作用下,浸泡冻融的冻融循环次数相同时,混凝土的峰值应力随溶液浓度的增加而有所增大,峰值应变随之左移,应力-应变曲线逐渐趋于平缓;相对于养护冻融,浸泡冻融条件下,随着侵蚀溶液浓度的增加,试件的峰值应力降低的少;(2)进行150次冻融循环试验后,随着复合盐侵蚀溶液浓度的增加,经浸泡冻融试验的混凝土试件的抗压强度分别降低了36.1%、35.9%、34.3%,而经养护冻融试验的混凝土试件的抗压强度分别降低了55.6%、59.9%、57.6%;(3)经扫描电镜(SEM)分析,随着复合盐侵蚀溶液浓度的增加,混凝土损伤程度减弱。The variation of stress-strain relationship of C30 concrete under multi-salt soaking and freezing-thawing was studied.The concentration of multi-salt （NaC1 ,Na2SO4,NaHCO3 and Na2CO3） is 3.5%, 10.5% and 17.5% respectively.Six groups （42） specimens of con- crete cube with dimensions of 100 mm×100 mm×l00 mm were exposed to rapid freeze-thaw and observed through SEM in order to detect damages caused by freeze-thaw action.The experimental results indicate that （ 1 ） The peak-value stress of concrete increases with the increase of time and solution concentration and the peak-value strain moves to the left when the freezing-thawing cycles were the same.The stress-strain curve of the corroded concrete becomes leveling off.Contrast to the maintenance freezing-thawing, under the immersion freez- ing,thawing, the peak-value stress of the specimen decreases less; （2）After the 150 times of freezing-thawing cycles, with the increase of multi-salt concentration, the compressive strength of concrete in the immersion freezing-thawing decreases by 36.1%, 35.9% and 34.3% re- spectively, and the compressive strength in the maintenance freezing and thawing decreases by 55.6%, 59.9% and 57.6% repectively; （3）The damage degree of concrete decreases with the increase of multi-salt concentration by SEM analysis.

关 键 词：混凝土 复合盐侵蚀 养护冻融 浸泡冻融 应力-应变曲线 微观分析 

分 类 号：TU528.01[建筑科学—建筑技术科学]