本文關(guān)鍵詞： 纖維混凝土 界面 拔出過程 纖維摻量　出處：《廣州大學(xué)》2015年碩士論文　論文類型：學(xué)位論文

【摘要】：纖維增強(qiáng)混凝土材料目前已經(jīng)迅速發(fā)展成為廣泛應(yīng)用在各工程領(lǐng)域的新型復(fù)合建筑材料,其中以鋼纖維與碳纖維混凝土材料發(fā)展最快。鋼纖維和碳纖維混凝土材料具有阻裂、增強(qiáng)和增韌的作用。鋼筋與混凝土可以共同工作的主要原因之一是兩種材料之間有效的粘結(jié)力。本文利用物理試驗(yàn)和數(shù)值模擬方法,結(jié)合聲發(fā)射技術(shù)手段,研究考慮界面控制的鋼筋從纖維混凝土基體中拔出的粘結(jié)滑移特性。利用RFPA2D和RFPA3D軟件,建立基于Weibull隨機(jī)分布的細(xì)觀非均勻損傷模型,將鋼筋與纖維混凝土之間的界面單獨(dú)作為一相,分析單根鋼筋從纖維混凝土基體中拔出的損傷破壞過程,重點(diǎn)研究了鋼筋的粘結(jié)長度、鋼纖維和碳纖維的摻量變化對鋼筋與纖維混凝土之間粘結(jié)滑移特性的影響。本文主要研究內(nèi)容如下:(1)研究纖維摻量的變化對纖維混凝土基體基本力學(xué)性能的影響。分別改變鋼纖維混凝土基體和碳纖維混凝土基體中的纖維摻量,運(yùn)用物理試驗(yàn)和數(shù)值模擬兩種方法進(jìn)行研究。物理試驗(yàn)中鋼纖維摻量為1.0%、1.2%和1.5%,碳纖維摻量為0.15%、0.20%、0.25%,制作6組不同的纖維混凝土立方體試塊并與普通混凝土立方體試塊進(jìn)行對比。在RFPA2D軟件中,建立纖維混凝土試塊單軸壓縮的數(shù)值模型,將數(shù)值模擬得到的聲發(fā)射與應(yīng)力應(yīng)變曲線的結(jié)果與物理試驗(yàn)得到的結(jié)果進(jìn)行對比,以驗(yàn)證數(shù)值模型中各相力學(xué)參數(shù)設(shè)置的合理性。(2)研究考慮界面的不同粘結(jié)長度對鋼筋從普通混凝土基體中拔出的粘結(jié)滑移特性的影響。首先,利用中心拔出物理試驗(yàn)?zāi)Ｐ?得到拔出力-拔出位移曲線;并運(yùn)用聲發(fā)射技術(shù)對整個拔出過程進(jìn)行監(jiān)測,得到不同粘結(jié)長度的鋼筋從混凝土基體中拔出的聲發(fā)射信號特征,與拔出力-拔出位移曲線進(jìn)行對比。其次運(yùn)用RFPA2D軟件建立水泥砂漿、粗骨料、鋼筋與混凝土基體之間的界面、鋼筋共四相的中心拔出數(shù)值模型,得到不同粘結(jié)長度的鋼筋從混凝土基體中拔出破壞的全過程,分析鋼筋與混凝土基體之間的界面單元信息,得到二維數(shù)值模擬情況下的界面剪應(yīng)力等性質(zhì);最后建立RFPA3D中心拔出數(shù)值模型,探討三維數(shù)值模型中不同粘結(jié)長度下的鋼筋從混凝土基體中拔出的粘結(jié)滑移特性。(3)研究纖維摻量對鋼筋從纖維混凝土基體中拔出的粘結(jié)滑移特性的影響,考慮鋼筋與纖維混凝土基體中的界面性質(zhì),分別改變鋼纖維與碳纖維的摻量,進(jìn)行物理試驗(yàn)和數(shù)值模擬研究,并利用聲發(fā)射手段對整個拔出過程進(jìn)行監(jiān)測。鋼筋粘結(jié)長度為5d(d為鋼筋直徑),最后得到鋼筋從纖維混凝土基體中拔出的力-位移曲線及聲發(fā)射信號特征。
[Abstract]:Fiber reinforced concrete materials have been rapidly developed into new types of composite building materials widely used in various engineering fields, among which steel fiber and carbon fiber reinforced concrete materials have the fastest development. Strengthening and toughening. One of the main reasons why the reinforcement and concrete can work together is the effective bonding force between the two materials. In this paper, we use physical test and numerical simulation method, combined with acoustic emission technology, The bond-slip behavior of steel bar pull-out from fiber reinforced concrete matrix considering interface control is studied. Using RFPA2D and RFPA3D software, a mesoscale nonuniform damage model based on Weibull random distribution is established. Taking the interface between steel bar and fiber concrete as a single phase, the damage and failure process of a single steel bar extracted from the fiber reinforced concrete matrix is analyzed, and the bond length of the steel bar is studied emphatically. The influence of the content of steel fiber and carbon fiber on the bond-slip behavior of steel fiber and fiber reinforced concrete. The main contents of this paper are as follows: 1) the influence of fiber content on the basic mechanical properties of fiber reinforced concrete matrix is studied. To change the fiber content in steel fiber reinforced concrete matrix and carbon fiber concrete matrix, In the physical test, the steel fiber content is 1.0% and 1.5%, and the carbon fiber content is 0.15% and 0.20%, 0.25% respectively. Six different groups of fiber concrete cube test blocks are made and compared with the ordinary concrete cube test blocks. In RFPA2D software, A numerical model for uniaxial compression of fiber reinforced concrete specimens is established. The results of acoustic emission and stress-strain curves obtained by numerical simulation are compared with those obtained from physical tests. In order to verify the reasonableness of setting mechanical parameters of each phase in the numerical model, the effect of different bond lengths of interface on the bond-slip behavior of steel bar pulled out from ordinary concrete matrix is studied. Firstly, the physical test model is drawn out by central pull-out. The drawing force-drawing displacement curve was obtained, and the acoustic emission technique was used to monitor the whole pull-out process, and the acoustic emission signal characteristics of the steel bars with different bonding lengths were obtained. Secondly, the interface between cement mortar, coarse aggregate, steel bar and concrete matrix and the central pull-out numerical model of four phases of steel bar are established by using RFPA2D software. The whole process of tensile failure of steel bar with different bonding length from concrete matrix is obtained. The information of interface element between steel bar and concrete matrix is analyzed and the properties of interface shear stress under two-dimensional numerical simulation are obtained. Finally, a numerical model of RFPA3D center pull-out is established. The effect of fiber content on the bond slip behavior of steel bar pull-out from concrete matrix is studied in the three-dimensional numerical model. Considering the interfacial properties of steel and fiber reinforced concrete matrix and changing the content of steel fiber and carbon fiber, the physical test and numerical simulation are carried out. The whole pull-out process is monitored by acoustic emission method. The bonding length of steel bar is 5 d and the diameter of steel bar is 5 d. Finally, the force-displacement curve and acoustic emission signal characteristics of steel bar drawn from fiber reinforced concrete matrix are obtained.
【學(xué)位授予單位】：廣州大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2015
【分類號】：TU528.57

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本文編號：1524402