【摘要】：實(shí)際結(jié)構(gòu)混凝土要受到各種作用而存在不同程度的損傷,損傷將影響侵蝕介質(zhì)的滲入,導(dǎo)致混凝土結(jié)構(gòu)耐久性發(fā)生較大的變化。不考慮損傷研究結(jié)構(gòu)混凝土耐久性會(huì)使研究結(jié)果偏離實(shí)際情況,使得人們對(duì)于混凝土結(jié)構(gòu)耐久性能和壽命的預(yù)期高于實(shí)際。因此,本文考慮造成結(jié)構(gòu)混凝土損傷的兩個(gè)主導(dǎo)因素：高溫和荷載,通過(guò)試驗(yàn)研究受損結(jié)構(gòu)混凝土的耐久性能。高溫?fù)p傷作用后混凝土耐久性能的研究方面：通過(guò)強(qiáng)度試驗(yàn)、RCM試驗(yàn)及超聲檢測(cè)方法分別測(cè)定了不同溫度作用下混凝土的剩余抗壓強(qiáng)度、氯離子遷移系數(shù)及超聲波速；通過(guò)干濕循環(huán)試驗(yàn)和RCT試驗(yàn)研究了高溫受損混凝土氯離子侵入規(guī)律,并擬合得到受損混凝土的氯離子擴(kuò)散系數(shù)；對(duì)相對(duì)聲速與其余三項(xiàng)指標(biāo)分別作了擬合；同時(shí)測(cè)定了高溫受損混凝土經(jīng)過(guò)水養(yǎng)護(hù)后的力學(xué)性能和耐久性能,研究了水養(yǎng)護(hù)對(duì)混凝土性能的修復(fù)效果。荷載損傷作用對(duì)混凝土耐久性能影響的研究方面：通過(guò)試驗(yàn)從荷載水平和受荷歷史兩個(gè)方面研究持續(xù)受壓混凝土的氯離子侵入規(guī)律,并考慮徐變的影響；通過(guò)試驗(yàn)研究了開(kāi)裂與未開(kāi)裂混凝土梁內(nèi)受拉區(qū)氯離子侵入規(guī)律,并考慮荷載水平和受荷歷史的影響。 高溫作用對(duì)混凝土耐久性能影響的研究方面,試驗(yàn)結(jié)果表明,隨著溫度升高,混凝土抗壓強(qiáng)度先上升后下降,氯離子遷移系數(shù)成非線性增長(zhǎng),超聲波速下降,氯離子擴(kuò)散系數(shù)增大。經(jīng)過(guò)水養(yǎng)護(hù)后,高溫?fù)p傷混凝土的力學(xué)性能和耐久性能均有不同程度的提高,且作用溫度越高,修復(fù)效果越好。相對(duì)聲速與受損混凝土的耐久性能有較好的相關(guān)性。 荷載對(duì)混凝土耐久性能影響的研究方面,試驗(yàn)結(jié)果表明,持續(xù)壓荷載作用下,混凝土的應(yīng)變隨荷載水平提高而增大,超聲波速隨荷載水平提高先基本保持不變,后增大,臨界水平為0.4,氯離子擴(kuò)散系數(shù)隨荷載水平先減小后增大,臨界水平在0.4左右,與超聲波速變化有較好的相關(guān)性。早齡期壓荷載對(duì)后期耐久性能影響較小。持續(xù)彎拉荷載作用下,未開(kāi)裂的混凝土梁純彎段氯離子擴(kuò)散系數(shù)隨荷載水平提高而增大；早齡期彎拉荷載對(duì)后期混凝土耐久性能影響也較��；開(kāi)裂混凝土梁內(nèi)氯離子侵入程度隨與裂縫的距離增大而下降。
[Abstract]:Actual structural concrete will be damaged by various kinds of actions, which will affect the infiltration of erosive medium and lead to great changes in the durability of concrete structure. The durability of concrete without damage study will make the research results deviate from the actual situation, which makes the durability performance and life expectancy of concrete structures higher than the actual ones. Therefore, in this paper, the durability of damaged concrete is studied by considering two main factors: high temperature and load. In terms of the durability of concrete after high temperature damage, the residual compressive strength, chloride transfer coefficient and ultrasonic velocity of concrete under different temperature were measured by RCM test and ultrasonic testing method. The chloride ion invasion law of high temperature damaged concrete is studied by dry and wet cycle test and RCT test, and the chloride diffusion coefficient of damaged concrete is obtained by fitting, and the relative sound velocity is fitted with the other three indexes respectively. At the same time, the mechanical properties and durability of high temperature damaged concrete after water curing were measured, and the effect of water curing on concrete performance was studied. The influence of load damage on the durability of concrete is studied. The chloride intrusion law of concrete under continuous compression is studied from two aspects of load level and loading history, and the influence of creep is considered. The influence of load level and load history on the chloride intrusion in the tensile zone of cracked and uncracked concrete beams is studied by experiments. As for the effect of high temperature on durability of concrete, the experimental results show that the compressive strength of concrete increases first and then decreases with the increase of temperature, the chloride ion transport coefficient increases nonlinear, and the ultrasonic velocity decreases. The chloride ion diffusion coefficient increases. After water curing, the mechanical properties and durability of high temperature damaged concrete are improved to some extent, and the higher the action temperature, the better the repair effect. The relative sound velocity has a good correlation with the durability of damaged concrete. The experimental results show that the strain of concrete increases with the increase of load level, and the ultrasonic velocity remains unchanged at first, then increases with the increase of load level. When the critical level is 0.4, the diffusion coefficient of chloride ion decreases first and then increases with the load level. The critical level is about 0.4, which has a good correlation with the change of ultrasonic velocity. The early age compressive load has little effect on the later durability. The chloride diffusion coefficient of pure flexural section of uncracked concrete beams increases with the increase of load level under continuous flexural load, and the early age flexural load has little effect on the durability of concrete in later stage. The degree of chloride invasion decreases with the increase of the distance between the crack and the crack.
【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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