中法常用水泥抗碳化性能的比较

发布时间：2018-04-18 01:23

  本文选题：快速碳化 + 水灰比　； 参考：《浙江科技学院》2017年硕士论文

【摘要】：钢筋锈蚀一直是各国钢筋混凝土建筑结构安全的最大隐患,钢筋混凝土中的钢筋表面有一层钝化膜可以阻碍其锈蚀,但包裹钢筋的混凝土若是失去碱性后发生碳化时,会导致钢筋表面钝化膜破坏,从而使钢筋发生锈蚀。钢筋锈蚀主要是由于混凝土碳化、氯离子引起钢筋去钝化和酸性介质引起的,而混凝土是否碳化关系到氯离子及酸性介质进入的关键,所以研究混凝土碳化尤为重要。要研究混凝土碳化缘由,水泥是混凝土组成材料中最易发生碳化的成分,因此最终解决水泥试块的碳化是解决钢筋混凝土结构破坏的关键所在。本论文研究中法两国常用水泥的抗碳化性能,目的在于了解两国用于实际工程建筑的水泥对钢筋混凝土建筑的耐久性的影响,并研究了水灰比、CO_2浓度、有无防水剂、预处理(碳化试验前)和水泥成分等因素对水泥试块的碳化的影响。得出以下结论:1)实验分别对0.45、0.50和0.55三组水灰比的试块进行抗碳化性能比较,实验结果显示,随着水灰比的增大,碳化程度增加。2)实验选用CO_2浓度为10%和20%,结果表明CO_2浓度越高,碳化越快。3)实验选用一组试块添加表面有机硅防水剂与不添加防水剂的试块进行碳化程度的比较,发现有防水剂的试块前7天碳化速度明显小于无防水剂的试块,且总的碳化深度也较低。4)预处理对于水泥胶砂试块碳化性能影响较为明显:一组试块成型后在60℃的烘干箱中干燥48h,另一组试块成型后在45℃的烘干箱中干燥14天,进行加速碳化。前者较后者碳化速度慢。5)中国和法国常用水泥成分不同,中国的常用水泥的碳化速度比法国常用水泥碳化速度更快。法国所用水泥中,CaO含量的成分相对较多,水化后的碱性物质更多,单位体积消耗的CO_2更多,所以碳化速度更慢。
[Abstract]:The corrosion of steel bars has always been the biggest hidden danger to the safety of reinforced concrete buildings in various countries. A passivation film on the surface of reinforced concrete bars can hinder its corrosion. However, if the reinforced concrete is carbonized after losing its alkalinity,This will lead to the destruction of the passivation film on the steel bar surface, which will lead to the corrosion of the steel bar.The corrosion of steel bar is mainly caused by carbonation of concrete, deactivation of steel bar by chloride ion and acid medium, and the carbonation of concrete is related to the key of chloride ion and acid medium, so it is very important to study the carbonation of concrete.In order to study the cause of concrete carbonation, cement is the most easily carbonated component of concrete. Therefore, the key to solve the structural damage of reinforced concrete is to solve the carbonation of concrete specimen.In this paper, the carbonation resistance of cement used in China and France is studied. The purpose of this paper is to understand the influence of cement used in practical construction on the durability of reinforced concrete buildings, and to study the concentration of water cement ratio of COSP 2 and the availability of water repellent.Effects of pretreatment (before carbonization test) and cement composition on carbonation of cement test blocks.The following conclusions are drawn: (1) the carbonization resistance of the three groups of water-cement ratio of 0.45 and 0.55 is compared with the ratio of water to cement. The experimental results show that with the increase of water-cement ratio, the carbonization degree increases with the increase of water-cement ratio.) the concentration of CO_2 is 10% and 20% respectively. The results show that the higher the concentration of CO_2 is, the higher the carbonization degree is.The faster the carbonization was, the faster the carbonization degree was compared between a group of test blocks with surface silicone water-repellent and those without water repellent. It was found that the carbonation rate of the sample with water repellent was obviously lower than that without water repellent in the first 7 days.The total carbonation depth was also lower. 4) Pretreatment had a significant effect on the carbonization properties of cement mortar sand. One group of samples was dried in oven at 60 鈩，

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