温湿度耦合作用下细观尺度混凝土裂缝扩展仿真
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摘要
早龄期混凝土拆模后易出现不同程度的裂缝,这在影响结构美观的同时,为后期承载埋下了隐患。为研究混凝土早龄期裂缝扩展机理,本文借助试验和仿真手段展开了分析。首先,以3组大体积混凝土构件为试验对象,借助温湿度数据采集系统对早龄期阶段混凝土裂缝扩展规律展开了试验研究;其次,提出了一种模拟温湿度耦合作用的实用新方法,对温湿度梯度引起的构件应力等问题进行了数值仿真;最后,基于细观尺度模型,编制了温湿度耦合作用下混凝土裂缝扩展程序,对早龄期混凝土开裂行为进行了数值模拟,并将模拟结果与试验对比。分析表明,早龄期裂缝集中出现在水化热反应最剧烈的阶段,裂缝形态以横向裂缝为主,分布呈现高随机性特征。数值仿真在一定程度上正确反映了试验结果。
A series of cracks may generate in early-age concrete after the formwork is dismantled,which is terrible for both the structural appearance and resisting loads.In order to investigate the crack propagation mechanism of the early-age concrete,a test is carried out and a simulation technique is adopted.Firstly,the experimental study was executed by means of the temperature and humidity data acquisition system,taking three mass concrete members as the tested object.Secondly,a new practical simulation method was proposed to acquire the stress data caused by both the temperature and humidity gradients.Finally,a crack propagation procedure was further developed to simulate the cracking behavior of the early-age concrete based on the meso-scale model.The analysis results indicate that most early-age cracks emerge at the most fierce stage of hydration reaction; transverse cracks are the majority and their distribution is high randomness.The simulation results reflect correctly the test observation to a certain extent.
A series of cracks may generate in early-age concrete after the formwork is dismantled,which is terrible for both the structural appearance and resisting loads.In order to investigate the crack propagation mechanism of the early-age concrete,a test is carried out and a simulation technique is adopted.Firstly,the experimental study was executed by means of the temperature and humidity data acquisition system,taking three mass concrete members as the tested object.Secondly,a new practical simulation method was proposed to acquire the stress data caused by both the temperature and humidity gradients.Finally,a crack propagation procedure was further developed to simulate the cracking behavior of the early-age concrete based on the meso-scale model.The analysis results indicate that most early-age cracks emerge at the most fierce stage of hydration reaction; transverse cracks are the majority and their distribution is high randomness.The simulation results reflect correctly the test observation to a certain extent.
引文
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[11] 王振红,朱岳明,武圈怀,等.混凝土热学参数试验与反分析研究[J].岩土力学,2009,30(6):1821-1825.
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[13] 陈德鹏,钱春香.考虑Knudsen扩散影响的水泥基材料湿扩散系数[J].建筑材料学报,2009(6):635-638.
[14] 朱伯芳.再论混凝土弹性模量的表达式[J].水利学报,1996(3):89-91.
[15] 王铁梦.工程结构裂缝控制 [M].北京:中国建筑工业出版社,1997.
[2] 陈德鹏,钱春香,缪昌文,等.计算混凝土湿热耦合变形的解析-有限元结合解法[J].东南大学学报(自然科学版),2010,40(增刊2):89-95.
[3] 郭利霞,陈守开,钟凌.混凝土结构的温湿耦合仿真计算[J].四川大学学报(工程科学版),2011,43(4):47-51.
[4] COMI C,KIRCHMAYR B,PIGNATELLI R.Two-phase damage modeling of concrete affected by alkali-silica reaction under variable temperature and humidity conditions [J].International Journal of Solids and Structures,2012,49(23):3367-3380.
[5] PETER A,MURUGESAN K,SHARMA U K,et al.Numerical study of heat and moisture transport through concrete at elevated temperatures [J].Journal of Mechanical Science and Technology,2014,28(5):1967-1977.
[6] ALQAM M,ALKAM M K.Temperature and moisture distribution inside a circular concrete column during the early stages of hydration [J].Canadian Journal of Civil Engineering,2014,41(6):559-568.
[7] 唐世斌.混凝土温湿型裂缝开裂过程细观数值模型研究[D].大连:大连理工大学,2009.
[8] RAO G A,PRASAD B K R.Influence of the roughness of aggregate surface on the interface bond strength [J].Cement & Concrete Research,2002,32(2):253-257.
[9] YANG C C.Effect of the transition zone on the elastic moduli of mortar [J].Cement & Concrete Research,1998,28(5):727-736.
[10] 盛宏玉,李和平,叶建乔,等.组合实心圆柱体热传导瞬态分析的状态变量法[J].上海交通大学学报,2011,45(2):247-251.
[11] 王振红,朱岳明,武圈怀,等.混凝土热学参数试验与反分析研究[J].岩土力学,2009,30(6):1821-1825.
[12] 袁勇.混凝土结构早期裂缝控制 [M].北京:科学出版社,2004.
[13] 陈德鹏,钱春香.考虑Knudsen扩散影响的水泥基材料湿扩散系数[J].建筑材料学报,2009(6):635-638.
[14] 朱伯芳.再论混凝土弹性模量的表达式[J].水利学报,1996(3):89-91.
[15] 王铁梦.工程结构裂缝控制 [M].北京:中国建筑工业出版社,1997.