基于CT扫描技术的沥青混合料虚拟劈裂试验  

Virtual splitting test of asphalt mixture based on computer tomography scanning technology

作　　者：李强[1,2] 张卓宇 罗桑 关永胜[4] LI Qiang;ZHANG Zhuoyu;LUO Sang;GUAN Yongsheng(College of Civil Engineering,Nanjing Forestry University,Nanjing 210037,China;National-Provincial Joint Engineering Research Center of Electromechanical Product Packaging,Nanjing 210037,China;School of Transportation,Southeast University,Nanjing 211189,China;Jiangsu Sino Road Transportation Science and Technology Co.Ltd.,Nanjing 211800,China)

机构地区：[1]南京林业大学土木工程学院,南京210037 [2]机电产品包装生物质材料国家地方联合工程研究中心,南京210037 [3]东南大学交通学院,南京211189 [4]江苏中路交通科学技术有限公司,南京211800

出　　处：《林业工程学报》2020年第1期164-170,共7页Journal of Forestry Engineering

基　　金：江苏省基础研究计划(自然科学基金)资助项目(BK20181404);江苏高校“青蓝工程”资助项目(苏教师(2016)15号);南京林业大学“青年骨干教师培养对象”资助项目(2017年)

摘　　要：为了研究不同类型沥青混合料的抗拉性能,采用Burgers模型表征沥青砂浆的黏弹性能,通过Computer Tomography(CT)扫描技术和有限元方法建立了基于沥青混合料细观结构特征的虚拟劈裂试验模型,并通过室内实测结果进行模型准确性验证。以劈裂劲度模量、拉应力最大值、拉应力平均值、拉应力方差以及应力集中性参数作为评价指标,分析了各细观结构因素对不同类型沥青混合料抗拉性能的影响。结果表明:分别从定性和定量方面证实了建立的沥青混合料虚拟劈裂试验模型具有较好的准确性;与AC-20混合料相比,AC-13混合料表现出更优的抗裂性能和应力分散能力;级配和集料分布特征均对沥青混合料抗裂性能造成影响;采用橡胶沥青或者SBS改性沥青可以显著增强沥青砂浆抗变形能力和沥青混合料抗拉性能;空隙的存在导致在一定程度上降低了沥青混合料的抗裂性能。因此,在进行虚拟仿真分析时必须准确地表征沥青混合料非均质的细观结构特征,才能有效地反映其宏观力学特性。The virtual test method can be used to discuss the mechanical responses of asphalt mixtures under the loading.The Burgers model is used to characterize the viscoelastic properties of asphalt mortar for investigating the tensile resistance of different asphalt mixtures.The computer tomography scanning technology and finite element method are used to develop the virtual splitting test model based on the microstructural characteristics.The model accuracy is verified by the measured results in the laboratory.Effects of microstructural characteristics on the tensile resistance of asphalt mixtures are analyzed by the indicators of splitting stiffness,maximum tensile stress,average tensile stress,variance of tensile stress,and stress concentration parameter.It is found that the developed model has a good accuracy in the qualitative and quantitative aspects.The relative errors are less than 10%for all cases.AC-13 mixtures show better cracking resistance and stress dispersion capacity than AC-20 ones.Aggregate gradations and distribution characteristics have effects on the cracking resistance of asphalt mixture.The geometric profile,spatial location,and combination form of aggregate particles play a significant role in the interlocking effect of aggregate structures.The difference in the aggregate distribution characteristics results in different cracking resistance for asphalt mixtures even under the same condition of aggregate gradation.Using crumb rubber and SBS modified asphalt binders can improve the deformation resistance of asphalt mortars and tensile performance of asphalt mixtures,respectively.The existing air voids can cause the higher tensile stress and the greater dispersion degree of tensile stress distribution in asphalt mixtures.The stress concentration phenomenon appears easily.It can lower the mixture cracking resistance to a certain extent.Therefore,the heterogeneous microstructural characteristics of asphalt mixtures must be captured in the virtual simulation analysis since aggregate gradations,aggregat

关 键 词：道路工程 沥青混合料 抗拉性能 有限元法 数字图像处理 CT扫描技术 

分 类 号：U416.217[交通运输工程—道路与铁道工程]