發(fā)布時間：2018-06-11 13:17

  本文選題：再生粗骨料 + 早期開裂��； 參考：《寧夏大學(xué)》2017年碩士論文

【摘要】：粗骨料是制備混凝土必不可少的原材料,現(xiàn)有的天然砂石粗骨料已經(jīng)難以維持混凝土粗骨料的可持續(xù)發(fā)展,因此必須要找到合適的天然粗骨料的替代品。整個地球每年都因舊建筑物、舊公路拆除而產(chǎn)生規(guī)模龐大的廢棄混凝土,這些廢棄混凝土又得不到有效的循環(huán)利用,因此研究再生混凝土的性能十分重要。這些廢棄混凝土塊經(jīng)過機(jī)械破碎、分級后,按一定的替代率與相應(yīng)的配合比可以制成再生粗骨料�，F(xiàn)在研究的大都是再生粗骨料混凝土的力學(xué)性能,而關(guān)于再生粗骨料混凝土的早期開裂及鋼纖維再生粗骨料混凝土早期開裂的研究是少之又少,同時試驗的復(fù)雜性和高成本性又限制了再生混凝土的發(fā)展,有限元數(shù)值模擬作為一種數(shù)值分析方法,即方便直觀又節(jié)省了試驗成本。因此,本文的主要研究內(nèi)容如下:(1)采用集中約束平板法,利用萬能試驗機(jī)及裂縫寬度觀測儀測取試驗數(shù)據(jù),通過分析試驗所得的數(shù)據(jù),研究了再生粗骨料對天然粗骨料的不同替代率、鋼纖維不同體積摻量對再生粗骨料混凝土 28天抗壓強(qiáng)度和早期開裂性能的影響,主要得出以下結(jié)論:①隨著再生粗骨料替代率的增加,再生混凝土的28d抗壓強(qiáng)度、28d抗劈裂強(qiáng)度,均表現(xiàn)出先增大后減小的趨向,當(dāng)替代率為60%時,抗壓強(qiáng)度達(dá)到最大值;隨著再生粗骨料替代率的增加,再生混凝土的24h水分蒸發(fā)速率、最大裂縫寬度、裂縫總面積先減少后增大。當(dāng)再生粗骨料對天然骨料的替代率為60%時,再生粗骨料混凝土板的開裂程度最小。②鋼纖維再生粗骨料混凝土板的28天抗壓強(qiáng)度隨著鋼纖維體積摻量的增加,而先降低后增加;其24h水分蒸發(fā)速率、最大裂縫寬度、裂縫總面積則整體表現(xiàn)出先降低后升高的趨向。再生粗骨料混凝土板的28d抗劈裂強(qiáng)度隨著鋼纖維體積摻量的增加而增高。當(dāng)鋼纖維的體積摻量達(dá)到0.8%,鋼纖維再生粗骨料混凝土板的早期開裂程度最小。(2)通過ANSYS完成有限元數(shù)值模擬,先選擇Solid70單元進(jìn)行熱分析,熱分析完成后,將Solid70單元轉(zhuǎn)換為Solid45單元,讀取熱分析結(jié)果,進(jìn)行結(jié)構(gòu)分析,得到再生粗骨料混凝土板的溫度應(yīng)力。得到溫度應(yīng)力后,重新建立有限元模型,采用Solid65單元進(jìn)行結(jié)構(gòu)分析,從而得到鋼纖維再生粗骨料混凝土早期開裂多少的情況。計算分析了鋼纖維不同體積摻量對鋼纖維再生混凝土板早期開裂的影響,數(shù)值模擬結(jié)果表明:鋼纖維再生混凝土板的早期開裂基本發(fā)生在裂縫誘導(dǎo)器附近,隨著鋼纖維體積摻量的增加,模型板裂縫的數(shù)量先減少后增加。當(dāng)鋼纖維體積摻量達(dá)到0.8%,有限元模型板的早期開裂最少;當(dāng)鋼纖維的體積摻量為1.2%時,雖然模型板的裂縫沒有沿裂縫誘導(dǎo)器分布,但是裂縫的數(shù)量最多。本文通過試驗研究再生粗骨料混凝土和鋼纖維再生粗骨料混凝土的早期開裂性能,通過ANSYS模擬鋼纖維再生粗骨料混凝土的早期開裂,試驗結(jié)果和數(shù)值模擬結(jié)果趨勢比較接近,給再生粗骨料混凝土用于工程實際提供了支持。
[Abstract]:Coarse aggregate is an essential raw material for the preparation of concrete. The existing natural aggregate coarse aggregate is difficult to maintain the sustainable development of the coarse aggregate of concrete. Therefore, it is necessary to find a suitable substitute for natural coarse aggregate. The whole earth is dismantled from old buildings and old roads to produce large scale of waste concrete every year. Concrete can not be recycled effectively, so it is very important to study the performance of recycled concrete. After being mechanically broken, these concrete blocks can be made into recycled coarse aggregate according to a certain substitution rate and corresponding mix ratio. Most of the research is on the mechanical properties of recycled coarse aggregate concrete. The early cracking of aggregate concrete and the early cracking of steel fiber recycled coarse aggregate concrete are few. At the same time, the complexity and high cost of the experiment restrict the development of recycled concrete. The finite element numerical simulation is a numerical analysis method, which is convenient and intuitive and saves the cost of the test. Therefore, the main research of this paper is the main research of this paper. The contents are as follows: (1) using the centralized constrained flat plate method, using the universal test machine and the crack width observatory to measure the experimental data. Through the analysis of the data obtained from the experiment, the different substitution rate of recycled coarse aggregate to natural coarse aggregate and the 28 day compressive strength and early cracking performance of the recycled coarse aggregate concrete with different volume of steel fiber are studied. The main conclusions are as follows: (1) with the increase of the replacement rate of recycled coarse aggregate, the 28d compressive strength of recycled concrete and the splitting strength of 28d show a tendency to increase first and then decrease. When the substitution rate is 60%, the compressive strength reaches the maximum. With the increase of the replacement rate of recycled coarse aggregate, the 24h moisture evaporation rate of recycled concrete is increased. When the replacement ratio of recycled coarse aggregate to natural aggregate is 60%, the cracking degree of recycled coarse aggregate concrete slab is the smallest. (2) the 28 day compressive strength of steel fiber recycled coarse aggregate concrete slab increases with the volume of steel fiber volume, and then increases first, and the water evaporation rate of 24h The maximum crack width and the total area of the crack show a tendency to decrease first and then increase. The 28d splitting strength of recycled coarse aggregate concrete plate increases with the increase of the volume of steel fiber. When the volume of steel fiber is 0.8%, the early cracking degree of the steel fiber recycled coarse aggregate concrete slab is the smallest. (2) complete through the completion of the steel fiber reinforced concrete slab. The finite element numerical simulation, first select the Solid70 unit for thermal analysis, after the thermal analysis is completed, the Solid70 unit is converted to Solid45 unit, the thermal analysis results are read, and the thermal stress of the recycled coarse aggregate concrete slab is obtained. After the thermal stress is obtained, the finite element model is rebuilt, and the structure analysis is carried out by the Solid65 element. The early cracking of steel fiber recycled coarse aggregate concrete was obtained. The effect of different volume of steel fiber on the early cracking of steel fiber recycled concrete slab was calculated and analyzed. The results of numerical simulation showed that the early cracking of the steel fiber recycled concrete slab was basically near the crack inducer, with the volume of steel fiber volume added. When the volume of steel fiber volume reaches 0.8%, the early cracking of the finite element model plate is the least. When the volume of steel fiber is 1.2%, the cracks in the model plate are not distributed along the crack inducer, but the number of the cracks is the most. The early cracking performance of steel fiber recycled coarse aggregate concrete was simulated by ANSYS to simulate the early cracking of steel fiber regenerated coarse aggregate concrete. The trend of experimental results and numerical simulation results was close, and it provided support for regenerated coarse aggregate concrete used in engineering practice.
【學(xué)位授予單位】：寧夏大學(xué)
【學(xué)位級別】：碩士
【學(xué)位授予年份】：2017
【分類號】：TU528

【參考文獻(xiàn)】

相關(guān)期刊論文 前10條

1 秦荷成;;聚丙烯纖維對再生混凝土早期抗裂性能影響的試驗研究[J];廣西水利水電;2013年03期

2 吳瑾;耿犟;楊曦;;短期荷載作用下再生骨料混凝土梁正截面裂縫寬度試驗研究[J];建筑結(jié)構(gòu)學(xué)報;2011年06期

3 馬漢英;劉志欣;;再生混凝土抗裂性能影響因素試驗研究[J];天津建設(shè)科技;2010年04期

4 吳瑾;丁東方;楊曦;;再生混凝土梁正截面開裂彎矩分析與試驗研究[J];建筑結(jié)構(gòu);2010年02期

5 肖建莊;劉瓊;李文貴;Vivian Tam;;再生混凝土細(xì)微觀結(jié)構(gòu)和破壞機(jī)理研究[J];青島理工大學(xué)學(xué)報;2009年04期

6 劉瓊;肖建莊;李宏;;老砂漿對再生混凝土力學(xué)性能影響模擬試驗[J];四川大學(xué)學(xué)報(工程科學(xué)版);2009年S1期

7 馬彥飛;徐曉勇;;配合比設(shè)計對再生混凝土劈裂抗拉強(qiáng)度的影響[J];江蘇建材;2009年01期

8 李平先;宋新偉;夏成;;鋼筋再生混凝土簡支梁的使用性能研究[J];建筑結(jié)構(gòu)學(xué)報;2008年S1期

9 周徽;柳炳康;陸國;;再生混凝土基本力學(xué)性能試驗分析[J];安徽建筑工業(yè)學(xué)院學(xué)報(自然科學(xué)版);2008年06期

10 夏廣政;夏冬桃;徐禮華;池寅;;混雜纖維增強(qiáng)混凝土深梁受彎性能試驗研究[J];華中科技大學(xué)學(xué)報(自然科學(xué)版);2007年11期

，

本文編號：2005380