受损结构混凝土的耐久性能研究
发布时间：2018-10-08 14:52
【摘要】：实际结构混凝土要受到各种作用而存在不同程度的损伤,损伤将影响侵蚀介质的渗入,导致混凝土结构耐久性发生较大的变化。不考虑损伤研究结构混凝土耐久性会使研究结果偏离实际情况,使得人们对于混凝土结构耐久性能和寿命的预期高于实际。因此,本文考虑造成结构混凝土损伤的两个主导因素：高温和荷载,通过试验研究受损结构混凝土的耐久性能。高温损伤作用后混凝土耐久性能的研究方面：通过强度试验、RCM试验及超声检测方法分别测定了不同温度作用下混凝土的剩余抗压强度、氯离子迁移系数及超声波速；通过干湿循环试验和RCT试验研究了高温受损混凝土氯离子侵入规律,并拟合得到受损混凝土的氯离子扩散系数；对相对声速与其余三项指标分别作了拟合；同时测定了高温受损混凝土经过水养护后的力学性能和耐久性能,研究了水养护对混凝土性能的修复效果。荷载损伤作用对混凝土耐久性能影响的研究方面：通过试验从荷载水平和受荷历史两个方面研究持续受压混凝土的氯离子侵入规律,并考虑徐变的影响；通过试验研究了开裂与未开裂混凝土梁内受拉区氯离子侵入规律,并考虑荷载水平和受荷历史的影响。 高温作用对混凝土耐久性能影响的研究方面,试验结果表明,随着温度升高,混凝土抗压强度先上升后下降,氯离子迁移系数成非线性增长,超声波速下降,氯离子扩散系数增大。经过水养护后,高温损伤混凝土的力学性能和耐久性能均有不同程度的提高,且作用温度越高,修复效果越好。相对声速与受损混凝土的耐久性能有较好的相关性。 荷载对混凝土耐久性能影响的研究方面,试验结果表明,持续压荷载作用下,混凝土的应变随荷载水平提高而增大,超声波速随荷载水平提高先基本保持不变,后增大,临界水平为0.4,氯离子扩散系数随荷载水平先减小后增大,临界水平在0.4左右,与超声波速变化有较好的相关性。早龄期压荷载对后期耐久性能影响较小。持续弯拉荷载作用下,未开裂的混凝土梁纯弯段氯离子扩散系数随荷载水平提高而增大；早龄期弯拉荷载对后期混凝土耐久性能影响也较小；开裂混凝土梁内氯离子侵入程度随与裂缝的距离增大而下降。
[Abstract]:Actual structural concrete will be damaged by various kinds of actions, which will affect the infiltration of erosive medium and lead to great changes in the durability of concrete structure. The durability of concrete without damage study will make the research results deviate from the actual situation, which makes the durability performance and life expectancy of concrete structures higher than the actual ones. Therefore, in this paper, the durability of damaged concrete is studied by considering two main factors: high temperature and load. In terms of the durability of concrete after high temperature damage, the residual compressive strength, chloride transfer coefficient and ultrasonic velocity of concrete under different temperature were measured by RCM test and ultrasonic testing method. The chloride ion invasion law of high temperature damaged concrete is studied by dry and wet cycle test and RCT test, and the chloride diffusion coefficient of damaged concrete is obtained by fitting, and the relative sound velocity is fitted with the other three indexes respectively. At the same time, the mechanical properties and durability of high temperature damaged concrete after water curing were measured, and the effect of water curing on concrete performance was studied. The influence of load damage on the durability of concrete is studied. The chloride intrusion law of concrete under continuous compression is studied from two aspects of load level and loading history, and the influence of creep is considered. The influence of load level and load history on the chloride intrusion in the tensile zone of cracked and uncracked concrete beams is studied by experiments. As for the effect of high temperature on durability of concrete, the experimental results show that the compressive strength of concrete increases first and then decreases with the increase of temperature, the chloride ion transport coefficient increases nonlinear, and the ultrasonic velocity decreases. The chloride ion diffusion coefficient increases. After water curing, the mechanical properties and durability of high temperature damaged concrete are improved to some extent, and the higher the action temperature, the better the repair effect. The relative sound velocity has a good correlation with the durability of damaged concrete. The experimental results show that the strain of concrete increases with the increase of load level, and the ultrasonic velocity remains unchanged at first, then increases with the increase of load level. When the critical level is 0.4, the diffusion coefficient of chloride ion decreases first and then increases with the load level. The critical level is about 0.4, which has a good correlation with the change of ultrasonic velocity. The early age compressive load has little effect on the later durability. The chloride diffusion coefficient of pure flexural section of uncracked concrete beams increases with the increase of load level under continuous flexural load, and the early age flexural load has little effect on the durability of concrete in later stage. The degree of chloride invasion decreases with the increase of the distance between the crack and the crack.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU37
本文编号：2257176
[Abstract]:Actual structural concrete will be damaged by various kinds of actions, which will affect the infiltration of erosive medium and lead to great changes in the durability of concrete structure. The durability of concrete without damage study will make the research results deviate from the actual situation, which makes the durability performance and life expectancy of concrete structures higher than the actual ones. Therefore, in this paper, the durability of damaged concrete is studied by considering two main factors: high temperature and load. In terms of the durability of concrete after high temperature damage, the residual compressive strength, chloride transfer coefficient and ultrasonic velocity of concrete under different temperature were measured by RCM test and ultrasonic testing method. The chloride ion invasion law of high temperature damaged concrete is studied by dry and wet cycle test and RCT test, and the chloride diffusion coefficient of damaged concrete is obtained by fitting, and the relative sound velocity is fitted with the other three indexes respectively. At the same time, the mechanical properties and durability of high temperature damaged concrete after water curing were measured, and the effect of water curing on concrete performance was studied. The influence of load damage on the durability of concrete is studied. The chloride intrusion law of concrete under continuous compression is studied from two aspects of load level and loading history, and the influence of creep is considered. The influence of load level and load history on the chloride intrusion in the tensile zone of cracked and uncracked concrete beams is studied by experiments. As for the effect of high temperature on durability of concrete, the experimental results show that the compressive strength of concrete increases first and then decreases with the increase of temperature, the chloride ion transport coefficient increases nonlinear, and the ultrasonic velocity decreases. The chloride ion diffusion coefficient increases. After water curing, the mechanical properties and durability of high temperature damaged concrete are improved to some extent, and the higher the action temperature, the better the repair effect. The relative sound velocity has a good correlation with the durability of damaged concrete. The experimental results show that the strain of concrete increases with the increase of load level, and the ultrasonic velocity remains unchanged at first, then increases with the increase of load level. When the critical level is 0.4, the diffusion coefficient of chloride ion decreases first and then increases with the load level. The critical level is about 0.4, which has a good correlation with the change of ultrasonic velocity. The early age compressive load has little effect on the later durability. The chloride diffusion coefficient of pure flexural section of uncracked concrete beams increases with the increase of load level under continuous flexural load, and the early age flexural load has little effect on the durability of concrete in later stage. The degree of chloride invasion decreases with the increase of the distance between the crack and the crack.
【学位授予单位】：浙江大学
【学位级别】：硕士
【学位授予年份】：2013
【分类号】：TU37
【参考文献】
相关期刊论文 前10条
1 郑丹;李鑫鑫;;混凝土在持续荷载下的强度[J];重庆交通大学学报(自然科学版);2010年02期
2 李敏;钱春香;;高强混凝土受火后抗渗透性能衰减规律[J];东南大学学报(自然科学版);2006年05期
3 薛文;王卫仑;龚顺风;金伟良;;干湿循环下氯离子在混凝土中的传输[J];低温建筑技术;2010年06期
4 曹蓓蓓,梁志刚;高温条件下混凝土结构与性能的变化[J];国外建材科技;2004年06期
5 李敏,钱春香,王珩,游有鲲,孙伟;高强混凝土受火后力学性能变化规律的研究[J];硅酸盐学报;2003年11期
6 方永浩,李志清,张亦涛;持续压荷载作用下混凝土的渗透性[J];硅酸盐学报;2005年10期
7 钱春香;游有鲲;李敏;;再养护液对受高温后高强混凝土的渗透性能的影响[J];硅酸盐学报;2006年02期
8 李敏,钱春香,孙伟;高强混凝土火灾后性能变化规律研究[J];工业建筑;2002年10期
9 刘利先,时旭东,过镇海;混凝土高温损伤后水中养护的愈合功能试验研究[J];工业建筑;2003年05期
10 孙洪梅,王立久,曹明莉;高铝水泥耐火混凝土火灾高温后强度及耐久性试验研究[J];工业建筑;2003年09期
相关博士学位论文 前1条
1 延永东;氯离子在损伤及开裂混凝土内的输运机理及作用效应[D];浙江大学;2011年
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