本文關(guān)鍵詞： 高性能再生混凝土 強化再生骨料 物理性能 力學性能 界面過渡區(qū) 疲勞性能　出處：《內(nèi)蒙古工業(yè)大學》2015年碩士論文　論文類型：學位論文

【摘要】：由于再生骨料混凝土自身存在諸多缺陷,近年來高強高性能再生混凝土的研究日益受到專家學者的關(guān)注。在研究再生混凝土基本物理力學性能的基礎(chǔ)上,本文著重研究了再生骨料高性能強化途徑、強化效果、高性能再生混凝土的界面特征以及高性能雙層再生混凝土梁的疲勞性能,主要內(nèi)容如下:首先,對再生骨料混凝土基本物理力學性能進行了研究,試驗結(jié)果表明:再生粗骨料與天然骨料相比表面更為粗糙,棱角較多且吸水率較大,壓碎值高,缺陷較為明顯。再生混凝土立方體抗壓強度、抗折強度、劈裂抗拉強度均低于同配比普通混凝土。通過正交試驗得出:粉煤灰摻量和再生骨料取代率是影響再生混凝土28d抗壓強度和抗折強度的兩個主要因素。第二,采用物理強化結(jié)合化學強化的再生粗骨料強化方法對再生粗骨料進行處理,結(jié)合二次攪拌法,較好的改善了再生骨料混凝土的工作性和力學性能。其中最優(yōu)處理方法為:先水洗去除粉塵,用5%HCL溶液處理,再用機械強化法去除松動的水泥砂漿殼,最后用1%EVA乳液處理得到強化再生粗骨料。與處理前相比,強化再生骨料24h吸水率降低22.7%,壓碎值降低26.5%,表觀密度提高12.5%。使用ESEM場發(fā)射電子掃描顯微鏡,觀察再生混凝土、普通混凝土以及高性能再生混凝土的界面結(jié)構(gòu)及水化產(chǎn)物,結(jié)果表明:再生混凝土中骨料與水泥石界面存在較明顯的微裂紋和較薄弱的過渡區(qū),強化處理方法使得再生混凝土界面過渡區(qū)得到了改善。第三,通過改變水膠比、砂率、強化再生粗骨料取代率,研究其對高性能再生混凝土工作性、28d立方體抗壓強度和抗折強度的影響。設(shè)計正交試驗研究了礦粉、水灰比、減水劑對高性能再生混凝土早齡期干縮性能的影響。得到滿足工作性、力學性能以及干縮性的高性能再生混凝土最優(yōu)配合比。最后,對雙層高性能再生混凝土梁疲勞試驗進行了研究。試驗表明:雙層高性能再生混凝土梁彎曲疲勞壽命能夠較好的服從兩對數(shù)威布爾分布。應(yīng)力水平為0.8時,使用取代率為30%強化再生骨料制成的高性能再生混凝土梁的抗疲勞性能優(yōu)于非強化再生混凝土梁;應(yīng)力比為0.7時,兩者接近。
[Abstract]:Due to the defects of recycled aggregate concrete, the research of high strength and high performance recycled concrete has been paid more and more attention by experts and scholars in recent years, based on the study of the basic physical and mechanical properties of recycled concrete. This paper focuses on the high performance of recycled aggregate strengthening way, strengthening effect, interface characteristics of high performance recycled concrete and fatigue performance of high performance double-layer recycled concrete beam. The main contents are as follows: first. The basic physical and mechanical properties of recycled aggregate concrete are studied. The experimental results show that the recycled coarse aggregate has more rough surface, more angles, higher water absorption and higher crushing value than natural aggregate. The defect is obvious. Recycled concrete cube compressive strength, flexural strength. The splitting tensile strength of concrete is lower than that of common concrete with the same ratio. The content of fly ash and the replacement ratio of recycled aggregate are two main factors affecting the compressive strength and flexural strength of recycled concrete for 28 days. The regenerated coarse aggregate was treated by physical strengthening combined with chemical strengthening and combined with secondary agitation. The workability and mechanical properties of recycled aggregate concrete were improved, and the optimal treatment methods were as follows: wash dust first, treat it with 5 HCL solution, and then remove loose cement mortar shell by mechanical strengthening method. At last, the recycled coarse aggregate was treated with 1 / EVA emulsion. Compared with the pre-treatment, the 24h water absorption of the reinforced recycled aggregate was reduced by 22.7and the crushing value was reduced by 26.5%. The apparent density was increased by 12.5. The interface structure and hydration products of recycled concrete, ordinary concrete and high performance recycled concrete were observed by ESEM field emission electron scanning microscope. The results show that there are obvious microcracks and weak transition zone in the interface between aggregate and cement stone in recycled concrete. By changing the water-binder ratio, sand ratio, and strengthening the replacement rate of recycled coarse aggregate, the effects of high performance recycled concrete on the compressive strength and flexural strength of high performance recycled concrete for 28 days were studied. The orthogonal test was designed to study the ore powder. The effect of water-cement ratio and water-reducing agent on the dry shrinkage performance of high performance recycled concrete at early age. The optimum mix ratio of high performance recycled concrete satisfying workability, mechanical property and dry shrinkage is obtained. Finally. The fatigue test of double-layer high performance recycled concrete beams is carried out. The results show that the fatigue life of double-layer high performance recycled concrete beams can be well distributed from two logarithmic Weibull distributions, and the stress level is 0.8. The fatigue resistance of high performance recycled concrete beams made of reinforced recycled aggregate with substitution ratio of 30% is better than that of non-reinforced recycled concrete beams. When the stress ratio is 0.7, the two are close.
【學位授予單位】：內(nèi)蒙古工業(yè)大學
【學位級別】：碩士
【學位授予年份】：2015
【分類號】：TU528

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相關(guān)博士學位論文 前1條

1 李九蘇;基于活性粉末增強的混凝土再生利用技術(shù)研究[D];湖南大學;2009年

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本文編號：1448805