本文選題：火災(zāi)高溫 + 再生混凝土　； 參考：《廣西大學(xué)》2015年碩士論文

【摘要】：近年來(lái),由于人口的高度集中、建筑火災(zāi)事故的頻發(fā),給人民的生命和財(cái)產(chǎn)帶來(lái)了嚴(yán)重?fù)p失。另一方面,伴隨著世界范圍內(nèi)大量建筑垃圾處理問(wèn)題的亟待解決以及建筑材料的巨大損耗和短缺,再生混凝土應(yīng)用于建筑結(jié)構(gòu)工程成為趨勢(shì)。因此,在再生混凝廣泛推廣應(yīng)用于結(jié)構(gòu)工程之前,有必要對(duì)于再生混凝土以及鋼筋再生混凝土受火災(zāi)高溫后的相關(guān)力學(xué)性能進(jìn)行研究。本文主要通過(guò)試驗(yàn)手段,結(jié)合相關(guān)理論分析,針對(duì)再生混凝土受高溫作用后的受壓應(yīng)力一應(yīng)變關(guān)系以及鋼筋再生混凝土受高溫作用后的粘結(jié)滑移性能進(jìn)行研究。完成的工作有：一、對(duì)經(jīng)過(guò)不同溫度作用后的天然混凝土和再生混凝土,采用超景深三維顯微系統(tǒng)對(duì)比觀察其受壓破壞后微觀裂縫的開展?fàn)顟B(tài),了解各個(gè)界面的粘結(jié)情況。二、通過(guò)對(duì)同強(qiáng)度再生混凝土受高溫作用后的單軸受壓試驗(yàn),研究了在不同再生粗骨料取代率和不同溫度條件下再生混凝土的應(yīng)力和應(yīng)變的特點(diǎn),并根據(jù)試驗(yàn)結(jié)果建立了再生混凝土受高溫作用后的應(yīng)力—應(yīng)變?nèi)�方程。三、通過(guò)中心拉拔試驗(yàn)研究了高溫后鋼筋與再生混凝土間的粘結(jié)滑移性能,揭示了在不同溫度條件、不同再生粗骨料取代率、不同相對(duì)保護(hù)層厚度c/d和有無(wú)橫向約束箍筋等條件影響下的粘結(jié)滑移性能,獲得了相應(yīng)的粘結(jié)—滑移曲線。四、依據(jù)損傷力學(xué)應(yīng)變等效性假設(shè)的相關(guān)理論知識(shí)分析了高溫后鋼筋與再生混凝土間的粘結(jié)滑移性能,定義粘結(jié)損傷變量D,計(jì)算得到損傷演變方程D-s關(guān)系曲線,建立了基于界面損傷的粘結(jié)—滑移本構(gòu)方程。主要研究結(jié)論如下：(1)采用三維顯微系統(tǒng)觀察和分析表明,在經(jīng)歷不同溫度作用后,天然混凝土破壞時(shí)內(nèi)部的薄弱面為骨料—砂漿界面；再生混凝土受壓破壞時(shí)內(nèi)部各個(gè)界面相對(duì)薄弱程度從重到輕依次為：舊骨料—新砂漿界面、舊砂漿—新砂漿界面和舊骨料—舊砂漿界面。(2)同一取代率條件下,受高溫作用后的再生混凝土試件的峰值應(yīng)力呈減小趨勢(shì),峰值應(yīng)變呈增大趨勢(shì),且所經(jīng)歷的溫度越高,峰值應(yīng)力越小,峰值應(yīng)變?cè)酱?峰值應(yīng)力最大損失為53.8%，峰值應(yīng)變最大增幅為270.1%。(3)當(dāng)試件經(jīng)歷溫度小于或等于400℃,在同一溫度下,隨著粗骨料取代率的增大,再生混凝土峰值應(yīng)力呈減小趨勢(shì),峰值應(yīng)變呈增大趨勢(shì)；當(dāng)試件經(jīng)歷溫度達(dá)到500。C后,出現(xiàn)了相反的規(guī)律,在同一溫度下,隨著取代率的增加,再生混凝土峰值應(yīng)力整體呈增大趨勢(shì),而峰值應(yīng)變呈減小趨勢(shì)。(4)在同一高溫條件作用后,取代率為100%的再生混凝土的峰值應(yīng)力均大于其他各取代率的結(jié)果,而峰值應(yīng)變則小于其他各取代率的峰值應(yīng)變。(5)不帶箍筋試件的主要破壞模式為劈裂破壞,帶箍筋試件的主要破壞模式為劈裂—拔出破壞。(6)同一取代率條件下,試件經(jīng)歷的溫度越高,試件峰值粘結(jié)應(yīng)力越小,峰值滑移量越大,溫度達(dá)500℃時(shí),峰值粘結(jié)應(yīng)力最大損失為66.2%,峰值滑移值最大增幅為126.4%。同時(shí),帶箍筋試件的平均峰值粘結(jié)應(yīng)力和平均峰值滑移值均要大于不帶箍筋試件的結(jié)果；相對(duì)保護(hù)側(cè)厚度c/d越大,則峰值粘結(jié)應(yīng)力越大,峰值滑移值也越大。(7)當(dāng)溫度在小于或等于400℃時(shí),每個(gè)溫度條件下均有一個(gè)最優(yōu)粗骨料取代率對(duì)抵抗試件的粘結(jié)滑移破壞最有利,而當(dāng)溫度達(dá)到500℃后,則是再生粗骨料取代率越大,對(duì)抵抗粘結(jié)滑移破壞越有利。
[Abstract]:In recent years, because of the high concentration of the population, the frequent occurrence of building fire accidents has brought serious loss to the people's life and property. On the other hand, with the problem of building garbage disposal in the world and the huge loss and shortage of building materials, the application of re concrete to the construction engineering has become a trend. Therefore, it is necessary to study the related mechanical properties of recycled concrete and regenerated concrete after fire and high temperature. This paper mainly deals with the stress-strain relationship of regenerated concrete under the effect of high temperature, and it is necessary to study the related mechanical properties of recycled concrete and regenerated concrete after fire and high temperature. The bond slip behavior of rebar regenerated concrete is studied by high temperature action. The work completed is: first, the natural concrete and recycled concrete after different temperatures are used, and the development state of the micro cracks after the compression failure is compared with the three dimensional microscopic system of ultra depth of field, and the bonding condition of each interface is understood. Two The stress and strain characteristics of recycled concrete under different recycled coarse aggregate and different temperature are studied after the uniaxial compression test of the same strength recycled concrete subjected to high temperature. According to the test results, the stress strain full curve equation of recycled concrete under high temperature is established. Three, through the central drawing The bond slip behavior between reinforced concrete and regenerated concrete after high temperature is studied. The bond slip curves are obtained under the influence of different temperature conditions, the substitution rate of recycled coarse aggregate, the thickness c/d of different relative protective layer and the transverse confinement stirrup. Four, according to the mechanics of damage. The related theoretical knowledge of the variable equivalence hypothesis is used to analyze the bond slip behavior between steel and recycled concrete after high temperature. The bond damage variable D is defined, and the D-s relation curve of the damage evolution equation is calculated. The bond slip constitutive equation based on the interface damage is established. The main conclusions are as follows: (1) the three-dimensional microscopic system observation and the analysis are as follows. The analysis shows that the internal weak surface is the aggregate mortar interface when the natural concrete is damaged by different temperatures, and the relative weak degree of the internal interfaces of the recycled concrete is in turn, the old aggregate - the new mortar interface, the old mortar - the new mortar interface and the old aggregate - the old mortar interface. (2) the same one. Under the condition of substitution, the peak stress of recycled concrete specimen after high temperature is decreased, and the peak strain is higher, the higher the peak stress, the greater the peak strain, the maximum peak stress loss 53.8%, the maximum strain of the peak strain 270.1%. (3), when the temperature is less than or equal to 400 C. At the same temperature, with the increase of the replacement rate of coarse aggregate, the peak stress of recycled concrete decreases and the peak strain shows an increasing trend. When the temperature reaches 500.C, the reverse regularity appears. At the same temperature, with the increase of the substitution rate, the peak stress of the regenerated concrete increases, and the peak strain shows the trend. (4) after the same high temperature condition, the peak stress of the recycled concrete with the substitution rate of 100% is greater than that of the other substitution rates, while the peak strain is less than the peak strain of other substitutional rates. (5) the main failure mode of the specimen without stirrups is splitting failure, and the main failure mode with the stirrup specimen is splitting. (6) under the same substitution rate, the higher the temperature of the specimen is, the smaller the peak bond stress is, the greater the peak slip, the maximum loss of the peak bond stress is 66.2%, the maximum peak slip value is 126.4%., and the average peak bond stress and the average peak slip value of the test pieces with stirrup are both large. The greater the relative protective side c/d, the larger the relative protective side thickness, the greater the peak bond stress, and the greater the value of the peak slip. (7) when the temperature is less than or equal to 400 C, there is an optimal coarse aggregate substitution rate under each temperature condition to resist the bond slip failure of the specimen, while the temperature reaches 500 degrees C. The greater the replacement rate of raw coarse aggregate is, the more favorable it is to resist bond slip failure.

【學(xué)位授予單位】：廣西大學(xué)
【學(xué)位級(jí)別】：碩士
【學(xué)位授予年份】：2015
【分類號(hào)】：TU398.9;TU352.5

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