吉林省西部地区受盐冻腐蚀混凝土受压构件受力性能的损伤研究

发布时间：2018-01-05 20:24

本文关键词：吉林省西部地区受盐冻腐蚀混凝土受压构件受力性能的损伤研究　出处：《长春工程学院》2017年硕士论文　论文类型：学位论文

【摘要】：吉林省西部地区既是东北典型的季冻区,也是土壤盐碱化最严重的地区之一。其境内土壤以碳酸(氢)盐为主,PH值较高,且土壤成分复杂,含有CO_3~(2-)、HCO_(3-)、SO_4~(2-)、Cl~-、Na~+、Mg~(2+)等离子。由于气候条件恶劣,此类地区的混凝土结构工程经常遭受各类盐(CO_3~(2-)、HCO_(3-)、SO_4~(2-)、Cl~-)侵蚀和冻融交替的双重作用,导致混凝土发生剥蚀破坏,进而加剧了周围环境中腐蚀性介质的侵入,加速混凝土保护层内钢筋的锈蚀和混凝土的胀裂,从而引起混凝土构件承载力下降和结构的失效与破坏,大大缩短了混凝土工程的使用寿命。目前,国内外学者更多关注冻融循环、氯盐或硫酸盐腐蚀等单一因素作用及氯盐或硫酸盐侵蚀与冻融双重因素下混凝土构件受压承载力的劣化问题;甚少关注吉林西部地区盐渍土环境下混凝土受压构件承载力性能的退化问题。因此,本文以吉林西部大安境内的混凝土工程为研究对象,开展了盐冻腐蚀作用后混凝土受压构件受力性能的损伤研究。制备混凝土构件(尺寸为120mm×120mm×600mm)放入质量分数分别为0、3.4%、10%的复合盐侵蚀溶液中进行快速冻融试验,以探究混凝土构件柱受压承载力随盐冻次数的损伤规律,为此类环境下混凝土结构的安全评价和耐久性设计提供参考。本文的主要研究工作及结论主要有:1.对冻融循环作用后的混凝土构件进行轴心受压试验,研究其冻融循环后受压承载力的损伤规律。结果表明:构件的质量、动弹性模量及承载能力均呈下降趋势,同时混凝土立方体试块的轴心抗压强度也随之降低。2.根据大安市境内土样中易溶盐的种类和含量配制复合盐侵蚀溶液,对复合盐溶液长期浸泡后的混凝土构件进行轴心受压试验,研究其轴心受压承载力的损伤规律。结果表明:盐蚀作用下混凝土构件破坏并不严重,其受压承载力的损伤程度随复合盐溶液质量分数的增加而增大。3.进行复合盐浸-冻融交替作用下混凝土构件的轴心受压试验,研究盐蚀-冻融双重因素作用后混凝土轴心受压构件承载力的损伤规律。结果表明:在盐蚀-冻融循环作用下,受压构件表层混凝土发生剥落,内部结构损伤严重,承载力下降明显;而且复合盐溶液的质量分数越高,混凝土构件破坏得越严重。另外,盐蚀-冻融循环作用下混凝土构件的损伤程度与速度远比单一因素(盐蚀、冻融)作用时严重迅速。4.通过对三组轴心受压试验得出的试验数据进行拟合,分别得出在盐蚀、冻融循环、盐蚀—冻融循环作用下混凝土构件受压承载力的计算损伤模型。
[Abstract]:The western part of Jilin Province is not only a typical seasonal frozen area in Northeast China, but also one of the most serious salinization areas. The soil in the region is dominated by carbonate (hydrogen) salt with high PH value and complex soil composition. Containing CO3 / C / 2 / HCOC / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C. Concrete structural projects in such areas are often subjected to the dual effects of various types of salt CO3C / C / H / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C / C. It leads to the erosion and destruction of concrete, which intensifies the invasion of corrosive medium in the surrounding environment, and accelerates the corrosion of steel bars in concrete cover and the expansion and cracking of concrete. Thus, the bearing capacity of concrete members decreases and the failure and failure of the structure, greatly shorten the service life of concrete engineering. At present, scholars at home and abroad pay more attention to freeze-thaw cycle. Single factor such as chloride or sulfate corrosion and deterioration of compressive capacity of concrete members under double factors of chloride or sulfate erosion and freeze-thaw; Little attention has been paid to the degradation of bearing capacity of concrete members under saline soil environment in the western part of Jilin Province. Therefore, this paper takes the concrete project in the west of Jilin Province as the research object. The damage of compressive concrete members subjected to salt frozen corrosion was studied. The weight fraction of prepared concrete members (120mm 脳 120mm 脳 600mm) was 0 respectively. The rapid freeze-thaw test was carried out in 10% of the composite salt erosion solution to investigate the damage law of the compressive capacity of concrete member column with the times of salt freezing. The main research work and conclusions of this paper are as follows: 1. The axial compression test of concrete members subjected to freeze-thaw cycle is carried out. The damage law of compression bearing capacity after freeze-thaw cycle is studied. The results show that the mass, dynamic elastic modulus and bearing capacity of the members are decreasing. At the same time, the axial compressive strength of concrete cube test block also decreased. 2. According to the species and content of soluble salt in soil samples in Da'an City, the compound salt erosion solution was prepared. The axial compression test was carried out to study the damage law of the bearing capacity of concrete members immersed in the composite salt solution for a long time. The results showed that the damage of concrete members under salt corrosion was not serious. The damage degree of the compressive bearing capacity increases with the increase of the mass fraction of the composite salt solution. 3. The axial compression test of concrete members under the combined salt immersion and freeze-thaw alternate action is carried out. The damage law of the bearing capacity of concrete axial compression members under the action of salt corrosion and freeze-thaw is studied. The results show that under the action of salt corrosion and freeze-thaw cycles, the surface concrete of compressive members spalling off. The internal structure is damaged seriously and the bearing capacity decreases obviously. Moreover, the higher the mass fraction of the composite salt solution, the more serious the damage of concrete members. In addition, the damage degree and speed of concrete members under the action of salt corrosion-freeze-thaw cycle is much higher than that of single factor (salt corrosion). By fitting the test data obtained from the three groups of axial compression tests, respectively, in salt erosion, freeze-thaw cycle. Damage model of compressive capacity of concrete members under salt corrosion-freeze-thaw cycle.
【学位授予单位】：长春工程学院
【学位级别】：硕士
【学位授予年份】：2017
【分类号】：TU37

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