混凝土结构锈裂二阶段理论及裂缝开展研究
发布时间：2018-08-16 17:43
【摘要】：要改变建筑工业的粗放型生产方式,实现可持续发展,一方面要提高混凝土结构的耐久性,另一方面要实现废混凝土的循环再生利用,推广再生混凝土的应用。混凝土中的钢筋锈蚀会对保护层产生锈胀压力,导致混凝土保护层开裂甚至剥落,严重影响混凝土结构的承载能力和耐久性,是引起钢筋混凝土结构耐久性破坏的最主要因素之一。而在再生混凝土中,复杂的骨料／砂浆界面和再生骨料内部的微裂缝等特殊的微观结构可能会对其锈裂过程带来多方面的影响。本文以混凝土结构的锈裂过程为研究对象,以试验研究和理论分析相结合的研究手段,对混凝土结构的锈裂机理进行了深入分析,并对再生混凝土的锈裂性能进行了研究和探讨。主要研究内容如下： (1)对钢筋混凝土构件锈裂过程中钢筋锈蚀产物在混凝土孔隙中和锈胀裂缝中的填充行为进行了深入的试验研究。通过对千湿循环加速锈蚀的钢筋混凝土试块进行SEM电镜扫描和EDX能谱分析,观察了钢筋／混凝土界面处的锈层结构,尤其关注铁锈在混凝土中的填充情况。对铁锈填充区域CP的分布进行了定量研究,并观察和分析了锈蚀产物在锈胀裂缝中的填充情况。 (2)基于试验研究成果,对锈裂过程“三阶段理论”进行了修正,提出了更符合实际锈裂过程的“二阶段理论”,并对已有的锈裂模型进行了改进,使其能够更接近真实的混凝土结构的锈裂过程。基于损伤力学和弥散裂缝的概念,对锈裂模型进行了发展,建立了保护层完全开裂阶段的锈裂模型,并基于模型的计算结果对于锈胀裂缝的开展规律进行了探讨。 (3)通过改进的干湿循环通电法对不同再生取代率的混凝土试块进行加速锈蚀,测量了混凝土保护层锈裂时刻的锈层厚度,以及锈胀裂缝随钢筋锈蚀程度的开展情况,并与理论模型的计算结果进行了对比验证。对影响再生混凝土锈裂过程的各种因素进行了分析和讨论,并讨论了试验结果对于再生混凝土的工程应用的参考意义。
[Abstract]:In order to change the extensive production mode of construction industry and realize sustainable development, on the one hand, the durability of concrete structure should be improved, on the other hand, the recycling and reuse of waste concrete should be realized, and the application of recycled concrete should be popularized. The corrosion of steel bars in concrete will cause corrosion expansion pressure on the protective layer, which will lead to cracking and even exfoliation of the concrete cover, which will seriously affect the bearing capacity and durability of concrete structure. It is one of the main factors that cause durability damage of reinforced concrete structure. In recycled concrete, the complex aggregate / mortar interface and the micro-cracks inside the recycled aggregate may have many effects on the process of rust cracking. In this paper, the rust cracking process of concrete structure is taken as the research object, and the mechanism of rust cracking of concrete structure is deeply analyzed by means of the combination of experimental research and theoretical analysis. The rust cracking property of recycled concrete is studied and discussed. The main research contents are as follows: (1) the filling behavior of steel corrosion products in concrete pores and corrosion expansion cracks during the process of corrosion cracking of reinforced concrete members is studied. By means of SEM scanning electron microscope and EDX energy dispersive analysis, the rust layer structure at the interface between steel bar and concrete was observed, especially the filling of rust in concrete. The distribution of CP in the rust filling region is quantitatively studied, and the filling of rust products in the rust expansion crack is observed and analyzed. (2) based on the experimental results, the "three-stage theory" of the rust cracking process is modified. The "two-stage theory" which is more in line with the actual rust cracking process is put forward, and the existing rust cracking model is improved to make it more close to the real rust cracking process of concrete structure. Based on the concept of damage mechanics and dispersion crack, the rust cracking model is developed, and the rust crack model of the protective layer is established in the stage of complete cracking. Based on the calculation results of the model, the rules of corrosion crack development are discussed. (3) accelerated corrosion of concrete specimens with different regeneration rates is carried out by the improved wet and dry cycle electrification method. The thickness of rust layer at the time of rust crack of concrete protective layer and the development of rust expansion crack with the corrosion degree of steel bar were measured and compared with the calculated results of theoretical model. Various factors affecting the process of rust cracking of recycled concrete are analyzed and discussed, and the reference significance of the test results for the engineering application of recycled concrete is discussed.
【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：2186709
[Abstract]:In order to change the extensive production mode of construction industry and realize sustainable development, on the one hand, the durability of concrete structure should be improved, on the other hand, the recycling and reuse of waste concrete should be realized, and the application of recycled concrete should be popularized. The corrosion of steel bars in concrete will cause corrosion expansion pressure on the protective layer, which will lead to cracking and even exfoliation of the concrete cover, which will seriously affect the bearing capacity and durability of concrete structure. It is one of the main factors that cause durability damage of reinforced concrete structure. In recycled concrete, the complex aggregate / mortar interface and the micro-cracks inside the recycled aggregate may have many effects on the process of rust cracking. In this paper, the rust cracking process of concrete structure is taken as the research object, and the mechanism of rust cracking of concrete structure is deeply analyzed by means of the combination of experimental research and theoretical analysis. The rust cracking property of recycled concrete is studied and discussed. The main research contents are as follows: (1) the filling behavior of steel corrosion products in concrete pores and corrosion expansion cracks during the process of corrosion cracking of reinforced concrete members is studied. By means of SEM scanning electron microscope and EDX energy dispersive analysis, the rust layer structure at the interface between steel bar and concrete was observed, especially the filling of rust in concrete. The distribution of CP in the rust filling region is quantitatively studied, and the filling of rust products in the rust expansion crack is observed and analyzed. (2) based on the experimental results, the "three-stage theory" of the rust cracking process is modified. The "two-stage theory" which is more in line with the actual rust cracking process is put forward, and the existing rust cracking model is improved to make it more close to the real rust cracking process of concrete structure. Based on the concept of damage mechanics and dispersion crack, the rust cracking model is developed, and the rust crack model of the protective layer is established in the stage of complete cracking. Based on the calculation results of the model, the rules of corrosion crack development are discussed. (3) accelerated corrosion of concrete specimens with different regeneration rates is carried out by the improved wet and dry cycle electrification method. The thickness of rust layer at the time of rust crack of concrete protective layer and the development of rust expansion crack with the corrosion degree of steel bar were measured and compared with the calculated results of theoretical model. Various factors affecting the process of rust cracking of recycled concrete are analyzed and discussed, and the reference significance of the test results for the engineering application of recycled concrete is discussed.
【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
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