【摘要】：混凝土與鋼筋之間良好的粘結(jié)性能是保證二者協(xié)同工作的重要基礎(chǔ)，隨著實際工程中耐久性問題越來越多地出現(xiàn)，鋼筋混凝土粘結(jié)性能的耐久性也自然的成為研究者們關(guān)注的焦點。已有的研究成果表明，鋼筋銹蝕已經(jīng)成為混凝土結(jié)構(gòu)耐久性最主要的影響因素之一，其對鋼筋混凝土粘結(jié)性能的影響也不可忽略，，但是由于銹蝕產(chǎn)物界面上的傳力機(jī)理復(fù)雜且影響因素眾多，兼之理論分析體系匱乏，因此十分有必要繼續(xù)展開對該領(lǐng)域的理論和試驗研究。 本文以已有的銹蝕鋼筋混凝土粘結(jié)性能退化試驗為基礎(chǔ)，通過對試塊銹蝕率和極限荷載數(shù)據(jù)進(jìn)行分析，得出結(jié)論：當(dāng)銹蝕率低于某值（約1%）時，極限荷載逐漸變大；當(dāng)銹蝕超過該值之后，極限荷載開始變小。說明在銹蝕率較低時，銹蝕產(chǎn)物的產(chǎn)生能在一定程度上提高鋼筋與混凝土之間的粘結(jié)性能。 同時，研究結(jié)果表明，粘結(jié)強(qiáng)度與極限滑移量的衰減受銹蝕量、混凝土保護(hù)層厚度以及混凝土抗拉強(qiáng)度等因素影響，相較于相對銹蝕率，鋼筋的絕對銹蝕量更能直觀反映銹蝕對銹脹力、銹蝕裂縫和粘結(jié)強(qiáng)度退化的影響機(jī)制，從而選取相互獨立的參數(shù)銹蝕產(chǎn)物厚度、混凝土相對保護(hù)層厚度與抗拉強(qiáng)度等，建立了多參數(shù)的銹蝕鋼筋混凝土粘結(jié)強(qiáng)度計算式，與國內(nèi)外及本文實驗結(jié)果的對比驗證了所選參數(shù)及所建模型的合理性。 通過在鋼筋內(nèi)部開槽并粘貼應(yīng)變片的方法，采集拉拔試驗過程中鋼筋的應(yīng)變，通過對鋼筋應(yīng)變數(shù)據(jù)和鋼筋加載端及自由端滑移值數(shù)據(jù)的分析，得到多參數(shù)的銹蝕鋼筋與混凝土之間的粘結(jié)-滑移關(guān)系。分析各因素對粘結(jié)剛度的影響，得出結(jié)論：粘結(jié)剛度隨著銹蝕產(chǎn)物層厚度t的增加而不斷減小；在產(chǎn)生相同滑移值的情況下，相對保護(hù)層厚度c/d越大，其粘結(jié)應(yīng)力水平越高，粘結(jié)剛度越大。 最后，通過分析銹蝕鋼筋混凝土粘結(jié)性能退化對梁抗彎剛度的影響機(jī)理，同時考慮鋼筋混凝土粘結(jié)性能退化及銹脹裂縫引起的梁橫截面初始缺陷對銹蝕梁抗彎剛度的影響，利用剛度解析法，推導(dǎo)出綜合考慮鋼筋應(yīng)變不協(xié)調(diào)系數(shù)m、修正后的裂縫鋼筋應(yīng)變不均勻系數(shù)'和有效高度折減系數(shù)γ的銹蝕梁抗彎剛度的計算模型。
[Abstract]:The good bond performance between concrete and steel bar is an important basis to ensure the cooperative work of the two. With the emergence of more and more durability problems in practical engineering, the durability of reinforced concrete bond performance has naturally become the focus of attention of researchers. The existing research results show that steel corrosion has become one of the most important factors affecting the durability of concrete structures, and its influence on the bond properties of reinforced concrete can not be ignored. However, due to the complexity of force transfer mechanism on the interface of corrosion products and the lack of theoretical analysis system, it is necessary to continue to carry out theoretical and experimental research in this field. In this paper, based on the existing bond degradation test of corroded reinforced concrete, through the analysis of the corrosion rate and ultimate load data of the test block, it is concluded that when the corrosion rate is lower than a certain value (about 1%), the ultimate load increases gradually, and when the corrosion exceeds this value, the ultimate load begins to decrease. It is shown that the formation of corrosion products can improve the bond between steel bar and concrete to a certain extent when the corrosion rate is low. At the same time, the results show that the attenuation of bond strength and ultimate slip is affected by corrosion, the thickness of concrete protective layer and the tensile strength of concrete. Compared with the relative corrosion rate, the absolute corrosion of steel bar can directly reflect the influence mechanism of corrosion on corrosion expansion force, corrosion crack and bond strength degradation, so as to select the independent parameter corrosion product thickness. Based on the relative protective layer thickness and tensile strength of concrete, a multi-parameter formula for calculating the bond strength of corroded reinforced concrete is established, and the rationality of the selected parameters and the model is verified by comparing with the experimental results at home and abroad and in this paper. Through the method of slotting and pasting strain gauge in the steel bar, the strain of the steel bar in the process of drawing test is collected. Through the analysis of the strain data of the steel bar and the slip value data of the loading end and the free end of the steel bar, the bond-slip relationship between the corroded steel bar and the concrete with multiple parameters is obtained. The influence of each factor on bond stiffness is analyzed, and it is concluded that the bond stiffness decreases with the increase of corrosion product layer thickness t, and the higher the relative protective layer thickness is, the higher the bond stress level is, and the greater the bond stiffness is when the relative protective layer thickness c 鈮

本文編號：2505800