三场耦合下路面混凝土界面区结构的损伤机制
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摘要
界面区是水泥混凝土结构中的薄弱区域,为揭示华北地区路面混凝土界面区结构在实际工作环境中的损伤机理,通过室内试验模拟路面混凝土在荷载、冻融和干湿三场耦合下的工作状态,采用数字图像处理技术对不同工作阶段的路面混凝土界面区结构进行图像提取与分析,揭示路面水泥混凝土在三场耦合下界面区结构的动态变化过程,进而研究三场耦合作用下路面水泥混凝土细观损伤机制.结果表明:标准养护3个月后混凝土的界面区宽度在30~40μm之间;随着荷载、冻融和干湿循环三场耦合作用时间的增长,混凝土疲劳寿命明显缩短,达到疲劳破坏时,界面区宽度接近60~70μm;三场耦合作用下界面区的扩展速度明显增加,混凝土的结构密实度逐渐降低,最大裂缝长度先延伸然后减小,而裂缝最大宽度则逐渐增加;最终确定了混凝土疲劳破坏时界面区宽度范围以及界面区结构破坏特征参数临界值.
The interfacial transition zone( ITZ) is a weak area in the cement concrete structure. In order to obtain the deterioration behavior of the ITZ suffering the working environment in North China,coupled loading condition of fatigue load,freeze-thaw cycles and dry-wet was conducted to simulate the working condition of pavement concrete.Digital image processing technology was used to extract and analyze the structure of pavement concrete interface area in different working stages,the dynamic process of the interface structure of the pavement cement concrete under the three fields was revealed,and then microcosmic damage mechanism of pavement cement concrete was studied.Results show that after three months of standard curing,the width of ITZ of concrete is between 30 ~ 40 μm; with the increase of the coupling time of load,freezing-thawing and dry-wet circulation,the fatigue life of concrete is obviously shortened,and when the fatigue damage is reached,the width of ITZ is close to 60 ~ 70 μm; the expansion rate of ITZ increases obviously,the structural density of the concrete decreases gradually,the maximum crack length extends first and then decreases,and the maximum width of the crack increases gradually; finally,the width of ITZ and the critical value of the structural parameters of ITZ are determined.
The interfacial transition zone( ITZ) is a weak area in the cement concrete structure. In order to obtain the deterioration behavior of the ITZ suffering the working environment in North China,coupled loading condition of fatigue load,freeze-thaw cycles and dry-wet was conducted to simulate the working condition of pavement concrete.Digital image processing technology was used to extract and analyze the structure of pavement concrete interface area in different working stages,the dynamic process of the interface structure of the pavement cement concrete under the three fields was revealed,and then microcosmic damage mechanism of pavement cement concrete was studied.Results show that after three months of standard curing,the width of ITZ of concrete is between 30 ~ 40 μm; with the increase of the coupling time of load,freezing-thawing and dry-wet circulation,the fatigue life of concrete is obviously shortened,and when the fatigue damage is reached,the width of ITZ is close to 60 ~ 70 μm; the expansion rate of ITZ increases obviously,the structural density of the concrete decreases gradually,the maximum crack length extends first and then decreases,and the maximum width of the crack increases gradually; finally,the width of ITZ and the critical value of the structural parameters of ITZ are determined.
引文
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[14]PANG B,ZHOU Z,CHENG X,et al. ITZ properties of concrete with carbonated steel slag aggregate in salty freeze-thaw environment[J]. Construction&Building Materials,2016,114:162-171.
[15]MILICA M VLAHOVIC',MAJA M Savic',SANJA P Martinovic',et al. Use of image analysis for durability testing of sulfur concrete and Portland cement concrete[J].Materials&Design,2012,34:346-354.
[16]NADEEM A,MEMON S A,LO T Y. Qualitative and quantitative analysis and identification of flaws in the microstructure of fly ash and metakaolin blended high performance concrete after exposure to elevated temperatures[J]. Construction&Building Materials,2013,38(2):731-741.
[17]吴浩,姚燕,王玲.数字图像处理技术在水泥混凝土研究中的应用[J].混凝土与水泥制品,2007(4):8-13.WU Hao,YAO Yan,WANG Ling. Application of digitalimage processing technology in cement concrete research[J]. China Concrete and Cement Products,2007(4):8-13.
[18]YANG X,SHEN A,GUO Y,et al. Deterioration mechanism of interface transition zone of concrete pavement under fatigue load and freeze-thaw coupling in cold climatic areas[J]. Construction&Building Materials,2018,160:588-597.
[19]韦江雄,余其俊,曾小星,等.混凝土中孔结构的分形维数研究[J].华南理工大学学报(自然科学版),2007,35(2):121-124.WEI Jiang-xiong,YU Qi-jun,ZENG Xiao-xing,et al.Fractal dimension of pore structure of concrete[J].Journal of South China University of Technology(Natural Science Edition),2007,35(2):121-124.
[20]陈洁,李其斌,杜亨,等.数学形态学在图像分割中的应用研究[J].计算机光盘软件与应用,2013(19):303-303.CHEN Jie,LI Qi-bin,DU Heng,et al. The application of mathematical morphology in image segmentation[J].Computer CD Software and Applications,2013(19):303-303.
[2]焦修刚,刘光廷.混凝土热湿耦合数值计算中的参数拟合[J].清华大学学报(自然科学版),2005,45(3):319-321.JIAO Xiu-gang,LIU Guang-ting. Parameter fitting in numerical analysis of coupled heat and mass transport in concrete[J]. Journal of Tsinghua University(Science&Technology),2005,45(3):319-321.
[3]耿飞,解建光,钱春香.图像分析技术对混凝土裂缝的定量评价[J].混凝土,2005(5):78-80.GENG Fei,XIE Jian-guang,QIAN Chun-xiang. Image analysis technique for quantitative evaluation of cracks in concrete[J]. Concrete,2005(5):78-80.
[4]GU X,HONG L,WANG Z,et al. Experimental study and application of mechanical properties for the interface between cobblestone aggregate and mortar in concrete[J].Construction&Building Materials,2013,46(46):156-166.
[5]SUN X,ZHANG B,DAI Q,et al. Investigation of internal curing effects on microstructure and permeability of interface transition zones in cement mortar with SEM imaging,transport simulation and hydration modeling techniques[J]. Construction&Building Materials,2015,76:366-379.
[6]LIZARAZO-MARRIAGA J,HIGUERA C,CLAISSE P.Measuring the effect of the ITZ on the transport related properties of mortar using electrochemical impedance[J]. Construction&Building Materials,2014,52(2):9-16.
[7]GAO Y,SCHUTTER G D,YE G. Micro-and meso-scale pore structure in mortar in relation to aggregate content[J]. Cement&Concrete Research,2013,52(10):149-160.
[8]吕惠卿,张湘伟,张荣辉.水泥混凝土路面断裂破坏研究[J].重庆交通大学学报(自然科学版),2010,29(1):54-57.LHui-qing,ZHANG Xiang-wei,ZHANG Rong-hui.Crack damage of cement concrete pavement[J]. Journal of Chongqing Jiaotong University(Natural Science),2010,29(1):54-57.
[9]LEEMANN A,MNCH B,GASSER P,et al. Influence of compaction on the interfacial transition zone and the permeability of concrete[J]. Cement&Concrete Research,2006,36(8):1425-1433.
[10]RANGARAJU P R,OLEK J,DIAMOND S. An investigation into the influence of inter-aggregate spacing and the extent of the ITZ on properties of Portland cement concretes[J]. Cement&Concrete Research,2010,40(11):1601-1608.
[11]水中和,万惠文.老混凝土中骨料-水泥界面过渡区(ITZ)(Ⅰ)——元素与化合物在ITZ的富集现象[J].武汉理工大学学报,2002,24(4):21-23.SHUI Zhong-he,WANG Hui-wen. Aggregate-Cement interfacial transition zone(ITZ)in old concrete(Ⅰ)—concentrations of elements and compounds to the ITZ[J]. Journal of Wuhan University of Technology,2002,24(4):21-23.
[12]CWIRZEN A,PENTTALA V. Aggregate-cement paste transition zone properties affecting the salt-frost damage of high-performance concretes[J]. Cement&Concrete Research,2005,35(4):671-679.
[13]SICAT E,GONG F,UEDA T,et al. Experimental investigation of the deformational behavior of the interfacial transition zone(ITZ)in concrete during freezing and thawing cycles[J]. Construction&Building Materials,2014,65(5):122-131.
[14]PANG B,ZHOU Z,CHENG X,et al. ITZ properties of concrete with carbonated steel slag aggregate in salty freeze-thaw environment[J]. Construction&Building Materials,2016,114:162-171.
[15]MILICA M VLAHOVIC',MAJA M Savic',SANJA P Martinovic',et al. Use of image analysis for durability testing of sulfur concrete and Portland cement concrete[J].Materials&Design,2012,34:346-354.
[16]NADEEM A,MEMON S A,LO T Y. Qualitative and quantitative analysis and identification of flaws in the microstructure of fly ash and metakaolin blended high performance concrete after exposure to elevated temperatures[J]. Construction&Building Materials,2013,38(2):731-741.
[17]吴浩,姚燕,王玲.数字图像处理技术在水泥混凝土研究中的应用[J].混凝土与水泥制品,2007(4):8-13.WU Hao,YAO Yan,WANG Ling. Application of digitalimage processing technology in cement concrete research[J]. China Concrete and Cement Products,2007(4):8-13.
[18]YANG X,SHEN A,GUO Y,et al. Deterioration mechanism of interface transition zone of concrete pavement under fatigue load and freeze-thaw coupling in cold climatic areas[J]. Construction&Building Materials,2018,160:588-597.
[19]韦江雄,余其俊,曾小星,等.混凝土中孔结构的分形维数研究[J].华南理工大学学报(自然科学版),2007,35(2):121-124.WEI Jiang-xiong,YU Qi-jun,ZENG Xiao-xing,et al.Fractal dimension of pore structure of concrete[J].Journal of South China University of Technology(Natural Science Edition),2007,35(2):121-124.
[20]陈洁,李其斌,杜亨,等.数学形态学在图像分割中的应用研究[J].计算机光盘软件与应用,2013(19):303-303.CHEN Jie,LI Qi-bin,DU Heng,et al. The application of mathematical morphology in image segmentation[J].Computer CD Software and Applications,2013(19):303-303.