本文選題：再生混凝土　切入點(diǎn)：數(shù)值分析　出處：《山東農(nóng)業(yè)大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：以均勻介質(zhì)假設(shè)為前提的宏觀力學(xué)方法研究再生骨料混凝土的力學(xué)性狀,不能深入探究再生混凝土的破壞機(jī)理,需要在細(xì)觀層次上研究再生混凝土內(nèi)部組分對(duì)其宏觀力學(xué)性能和破壞過程的影響。本文采用基于真實(shí)骨料模型的數(shù)值分析方法,對(duì)再生混凝土破壞過程、力學(xué)性能及影響因素等展開了系列研究。應(yīng)用MATLAB圖像處理軟件對(duì)再生混凝土試件圖片進(jìn)行圖形前處理、分段變換、中值濾波除噪、邊緣檢測(cè)和幾何矢量轉(zhuǎn)換,建立的再生混凝土真實(shí)骨料數(shù)值模型。在細(xì)觀尺度上將再生混凝土分為六相組分:天然骨料、老砂漿、新砂漿、新砂漿和天然骨料界面過渡區(qū)、新砂漿和老砂漿界面過渡區(qū)、老砂漿和天然骨料界面過渡區(qū)。根據(jù)再生混凝土各相組分的力學(xué)特性,利用自動(dòng)動(dòng)態(tài)增量非線性分析軟件ADINA對(duì)再生混凝土單軸拉伸及壓縮作用下細(xì)觀損傷過程和宏觀力學(xué)性能變化進(jìn)行了模擬分析。對(duì)模擬結(jié)果和試驗(yàn)結(jié)果進(jìn)行對(duì)比分析,驗(yàn)證了建立的再生混凝土真實(shí)細(xì)觀數(shù)值模型的合理性。在此基礎(chǔ)上,對(duì)再生混凝土進(jìn)行變參數(shù)分析,討論不同天然骨料、界面過渡區(qū)和新老硬化砂漿的力學(xué)特性對(duì)再生混凝土宏觀力學(xué)性能的影響。研究結(jié)論表明:與混凝土隨機(jī)骨料細(xì)觀模型比較,真實(shí)骨料模型的模擬結(jié)果與試驗(yàn)結(jié)果吻合較好,真實(shí)骨料模型能更好地模擬荷載作用下的再生混凝土的破壞過程;天然骨料彈性模量較其他各相組分大,對(duì)再生混凝土宏觀剛度和強(qiáng)度影響較小,在其周邊界面過渡區(qū)易產(chǎn)生應(yīng)力集中,影響再生混凝土的破壞過程和裂縫擴(kuò)展路徑;再生混凝土宏觀強(qiáng)度和剛度均隨新砂漿力學(xué)性能的變化而變化,老砂漿性能對(duì)再生混凝土宏觀性能影響較小;再生混凝土的新老界面處存在拉應(yīng)力和剪應(yīng)力集中現(xiàn)象,新老界面強(qiáng)度對(duì)再生混凝土宏觀力學(xué)性能影響較小。本文結(jié)論可為再生混凝土結(jié)構(gòu)和構(gòu)件的力學(xué)分析及應(yīng)用安全等提供技術(shù)支持,同時(shí)為進(jìn)一步研究再生混凝土的細(xì)微觀性能提供參考。
[Abstract]:The mechanical properties of recycled aggregate concrete can not be studied by macroscopic mechanical method based on the assumption of homogeneous medium, and the failure mechanism of recycled concrete can not be deeply explored. It is necessary to study the influence of internal components of recycled concrete on its macroscopic mechanical properties and failure process at the meso level. In this paper, a numerical analysis method based on real aggregate model is used to analyze the failure process of recycled concrete. A series of studies on mechanical properties and influencing factors were carried out. Using MATLAB image processing software, the image of regenerated concrete specimen was processed by image pre-processing, segmental transformation, median filtering and noise removal, edge detection and geometric vector conversion. The real aggregate numerical model of recycled concrete is established. The recycled concrete is divided into six phase components at meso scale: natural aggregate, old mortar, new mortar, new mortar and natural aggregate interface transition zone, new mortar and old mortar interface transition zone, Interface transition zones between old mortar and natural aggregates. Based on the mechanical properties of each phase component of recycled concrete, The microscopic damage process and macroscopic mechanical properties of recycled concrete under uniaxial tension and compression were simulated and analyzed by using the automatic dynamic increment nonlinear analysis software ADINA. The simulation results were compared with the experimental results. The rationality of the real mesoscopic numerical model of recycled concrete is verified. On the basis of this, the variable parameter analysis of recycled concrete is carried out, and the different natural aggregates are discussed. The effect of the mechanical properties of the interfacial transition zone and the new and old hardened mortar on the macroscopic mechanical properties of recycled concrete is studied. The results show that the simulation results of the real aggregate model are in good agreement with the experimental results compared with the concrete random aggregate meso model. The real aggregate model can better simulate the failure process of recycled concrete under load, and the elastic modulus of natural aggregate is larger than that of other phases, which has little effect on the macro stiffness and strength of recycled concrete. It is easy to produce stress concentration in the transition zone of its peripheral interface, which affects the failure process and crack propagation path of recycled concrete, and the macroscopic strength and stiffness of recycled concrete vary with the mechanical properties of new mortar. The properties of old mortar have little influence on the macro performance of recycled concrete, and there are tensile stress and shear stress concentration at the new and old interface of recycled concrete. The new and old interface strength has little influence on the macro mechanical properties of recycled concrete. The conclusion of this paper can provide technical support for mechanical analysis and application safety of recycled concrete structures and members. At the same time, it provides a reference for the further study of the fine properties of recycled concrete.
【學(xué)位授予單位】：山東農(nóng)業(yè)大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU528

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本文編號(hào)：1592405