复合盐侵-冻融环境下混凝土的应力-应变关系试验研究
发布时间：2018-11-27 19:40
【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。
[Abstract]:The concrete was corroded by 3.5% and 10.5% of the compound salt (NaCl,Na_2SO_4,NaHCO_3,Na_2CO_3) solution, The stress-strain relationship of C30 concrete under the action of composite salt erosion and freeze-thaw cycle was studied. Six groups of concrete cube specimens with size of 100 mm 脳 100 mm were subjected to freeze-thaw cycle. The microstructure of concrete after freezing and thawing was observed by SEM scanning electron microscope. The results show that: (1) when the freezing and thawing cycles are the same, the peak stress of concrete increases with the increase of solution concentration, and the peak strain shifts to the left. The stress-strain curve tends to be gentle; Compared with the curing freezing and thawing, the peak stress of the specimen decreases with the increase of the concentration of corrosion solution under the condition of immersion freezing and thawing. (2) after 150 freeze-thaw cycle tests, with the increase of the concentration of the composite salt erosion solution, the compressive strength of the concrete specimens subjected to immersion freezing and thawing test decreased by 36.1% and 35.9% respectively. The compressive strength of the concrete specimens tested by the curing freeze-thaw test has been reduced by 55.69.9and 57.6respectively. (3) (SEM) analysis shows that the damage degree of concrete decreases with the increase of the concentration of complex salt solution.
【作者单位】： 华北水利水电大学土木与交通学院;
【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)
【分类号】：TU528
本文编号：2361841
[Abstract]:The concrete was corroded by 3.5% and 10.5% of the compound salt (NaCl,Na_2SO_4,NaHCO_3,Na_2CO_3) solution, The stress-strain relationship of C30 concrete under the action of composite salt erosion and freeze-thaw cycle was studied. Six groups of concrete cube specimens with size of 100 mm 脳 100 mm were subjected to freeze-thaw cycle. The microstructure of concrete after freezing and thawing was observed by SEM scanning electron microscope. The results show that: (1) when the freezing and thawing cycles are the same, the peak stress of concrete increases with the increase of solution concentration, and the peak strain shifts to the left. The stress-strain curve tends to be gentle; Compared with the curing freezing and thawing, the peak stress of the specimen decreases with the increase of the concentration of corrosion solution under the condition of immersion freezing and thawing. (2) after 150 freeze-thaw cycle tests, with the increase of the concentration of the composite salt erosion solution, the compressive strength of the concrete specimens subjected to immersion freezing and thawing test decreased by 36.1% and 35.9% respectively. The compressive strength of the concrete specimens tested by the curing freeze-thaw test has been reduced by 55.69.9and 57.6respectively. (3) (SEM) analysis shows that the damage degree of concrete decreases with the increase of the concentration of complex salt solution.
【作者单位】： 华北水利水电大学土木与交通学院;
【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)
【分类号】：TU528
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