西宁盐渍土地区混凝土劣化机理试验研究

发布时间：2018-03-21 09:36

本文选题：混凝土　切入点：盐渍土　出处：《应用基础与工程科学学报》2017年04期 　论文类型：期刊论文

【摘要】：对不同组混凝土试件在多种情况下进行了耐久性试验,结合试验数据选取试件的相对质量评价参数和相对动弹性模量评价参数作为评价指标,探究了混凝土的表观损伤特征、相对质量及相对动弹性模量的变化规律,同时对不同组混凝土试件取样进行电镜扫描、EDS能谱分析及化学成分测定,以揭示混凝土的微观结构及损伤劣化机理.研究结果表明,相对质量评价参数和相对动弹性模量评价参数能直观地表征混凝土的劣化过程;西宁盐渍土地区混凝土的破坏形式为盐分的化学腐蚀和物理结晶,化学腐蚀对混凝土劣化具有加速效应,二者相互作用使混凝土发生了严重的破坏,主要的腐蚀产物有石膏、碳酸钙及硅灰石膏,特别地在西宁盐渍土地区混凝土发现了更为危害的硅灰石膏型硫酸盐侵蚀;西宁地区现场暴露混凝土已经受到盐渍土的侵蚀,其评价参数波动性变化,经过1 230d的试验还处于劣化初期.
[Abstract]:In this paper, durability tests of concrete specimens of different groups are carried out under various conditions. According to the test data, the relative quality evaluation parameters and the relative dynamic elastic modulus evaluation parameters of the specimens are selected as the evaluation indexes, and the apparent damage characteristics of concrete are explored. The changes of relative mass and relative dynamic modulus of elasticity were analyzed by scanning electron microscope (SEM) EDS spectrum analysis and chemical composition analysis to reveal the microstructure of concrete and the mechanism of damage deterioration. The relative quality evaluation parameters and the relative dynamic elastic modulus evaluation parameters can directly characterize the deterioration process of concrete, and the failure forms of concrete in Xining saline soil area are chemical corrosion of salt and physical crystallization. Chemical corrosion has an accelerated effect on the deterioration of concrete, and the interaction of the two causes serious damage to concrete. The main corrosion products are gypsum, calcium carbonate and wollastonite paste, the main corrosion products of which are gypsum, calcium carbonate and wollastonite paste. In particular, more harmful wollastonite gypsum sulfate erosion has been found in concrete in Xining saline soil area, and the field exposed concrete in Xining area has been eroded by saline soil, and its evaluation parameters fluctuate. After 1 230 days of test, it is still in the initial stage of deterioration.
【作者单位】：兰州理工大学甘肃省土木工程防灾减灾重点实验室;西部土木工程防灾减灾教育部工程研究中心;
【基金】：国家自然科学基金项目(51168031,51468039)
【分类号】：TU528

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