【摘要】：要改變建筑工業(yè)的粗放型生產(chǎn)方式,實(shí)現(xiàn)可持續(xù)發(fā)展,一方面要提高混凝土結(jié)構(gòu)的耐久性,另一方面要實(shí)現(xiàn)廢混凝土的循環(huán)再生利用,推廣再生混凝土的應(yīng)用。混凝土中的鋼筋銹蝕會(huì)對(duì)保護(hù)層產(chǎn)生銹脹壓力,導(dǎo)致混凝土保護(hù)層開裂甚至剝落,嚴(yán)重影響混凝土結(jié)構(gòu)的承載能力和耐久性,是引起鋼筋混凝土結(jié)構(gòu)耐久性破壞的最主要因素之一。而在再生混凝土中,復(fù)雜的骨料／砂漿界面和再生骨料內(nèi)部的微裂縫等特殊的微觀結(jié)構(gòu)可能會(huì)對(duì)其銹裂過程帶來多方面的影響。本文以混凝土結(jié)構(gòu)的銹裂過程為研究對(duì)象,以試驗(yàn)研究和理論分析相結(jié)合的研究手段,對(duì)混凝土結(jié)構(gòu)的銹裂機(jī)理進(jìn)行了深入分析,并對(duì)再生混凝土的銹裂性能進(jìn)行了研究和探討。主要研究內(nèi)容如下： (1)對(duì)鋼筋混凝土構(gòu)件銹裂過程中鋼筋銹蝕產(chǎn)物在混凝土孔隙中和銹脹裂縫中的填充行為進(jìn)行了深入的試驗(yàn)研究。通過對(duì)千濕循環(huán)加速銹蝕的鋼筋混凝土試塊進(jìn)行SEM電鏡掃描和EDX能譜分析,觀察了鋼筋／混凝土界面處的銹層結(jié)構(gòu),尤其關(guān)注鐵銹在混凝土中的填充情況。對(duì)鐵銹填充區(qū)域CP的分布進(jìn)行了定量研究,并觀察和分析了銹蝕產(chǎn)物在銹脹裂縫中的填充情況。 (2)基于試驗(yàn)研究成果,對(duì)銹裂過程“三階段理論”進(jìn)行了修正,提出了更符合實(shí)際銹裂過程的“二階段理論”,并對(duì)已有的銹裂模型進(jìn)行了改進(jìn),使其能夠更接近真實(shí)的混凝土結(jié)構(gòu)的銹裂過程。基于損傷力學(xué)和彌散裂縫的概念,對(duì)銹裂模型進(jìn)行了發(fā)展,建立了保護(hù)層完全開裂階段的銹裂模型,并基于模型的計(jì)算結(jié)果對(duì)于銹脹裂縫的開展規(guī)律進(jìn)行了探討。 (3)通過改進(jìn)的干濕循環(huán)通電法對(duì)不同再生取代率的混凝土試塊進(jìn)行加速銹蝕,測量了混凝土保護(hù)層銹裂時(shí)刻的銹層厚度,以及銹脹裂縫隨鋼筋銹蝕程度的開展情況,并與理論模型的計(jì)算結(jié)果進(jìn)行了對(duì)比驗(yàn)證。對(duì)影響再生混凝土銹裂過程的各種因素進(jìn)行了分析和討論,并討論了試驗(yàn)結(jié)果對(duì)于再生混凝土的工程應(yīng)用的參考意義。
[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.
【學(xué)位授予單位】：浙江大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2013
【分類號(hào)】：TU37

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