基于拉压模量同步测试的岩沥青改性沥青混合料疲劳损伤特性  

Fatigue Damage Characteristics of Rock Asphalt Modified Asphalt Mixtures Based on Tension and Compression Moduli Synchronous Test

作　　者：郭彤 杨毅 夏诚东[2] 杨倪坤 GUO Tong;YANG Yil,;XIA Cheng-dong;YANG Ni-kun(Modern investment Co. , Ltd. , Changsha Hunan 410004, China;Changsha University of Science ＆ Technology, Changsha Hunan 410114, China)

机构地区：[1]现代投资股份有限公司,湖南长沙410004 [2]长沙理工大学,湖南长沙410114

出　　处：《公路交通科技》2018年第6期14-21,共8页Journal of Highway and Transportation Research and Development

基　　金：国家自然科学基金项目(51578081)

摘　　要：为了揭示岩沥青作为改性剂对沥青混合料疲劳性能的影响,利用MTS材料试验系统对岩沥青改性沥青混合料进行了四点弯曲疲劳试验,并对比了其与SBS改性沥青混合料的疲劳性能,分析了岩沥青对基质沥青混合疲劳性能的改善效果;定义模量衰减为损伤变量,基于四点弯曲拉、压弯模量同步测试法同时得到沥青混合料拉、压和弯曲回弹模量,建立了沥青混合料不同模量衰变方程。研究结果表明:岩沥青加入基质沥青混合料能显著改善其疲劳性能,与SBS改性沥青混合料疲劳性能相当;从拉、压、弯模量衰减斜率绝对值大小来看,拉伸模量斜率最大,其次是弯拉模量,压缩模量斜率最小;临界破坏时拉伸模量的衰减比大于压缩模量的衰减比,即试件发生开裂破坏并非是压缩模量的衰减所导致,而是由拉伸模量衰减过快引起的,导致中性面以下受拉区域损伤累积加剧,最先发生开裂,为试件的破坏源;在弯拉疲劳应力状态下,沥青混合料的拉、压模量衰变规律具有较大的差异性,拉伸模量衰变速率大于压缩模量衰变速率,因此在受拉区将产生较大的损伤,说明了模量衰变曲线稳定阶段拉伸模量衰减速率的过快及衰减末期压缩模量破坏点的滞后性,同时也间接反映出拉伸模量衰变速率的快慢是决定沥青混合料疲劳性能是否优越的关键因素。In order to reveal the impact of rock asphalt as modifier on the fatigue property of asphalt mixture, the 4-point bending fatigue test on the rock asphalt modified asphalt mixture is conducted with material test system （MTS）, its fatigue property is compared with that of SBS modified asphalt mixture, and the improvement effect of rock asphalt on the fatigue property of matrix asphalt mixture is analyzed. Defining modulus decay as damage variable, the tension, compression and bending resilient moduli of asphalt mixture are obtained by 4-point bending tension and compression moduli synchronous test method, and the different moduli decay equations of asphalt mixture are derived. The result shows that （ 1 ） The fatigue property of rock asphalt modified asphalt mixture can be significantly improved, which is similar to that of SBS modified asphalt mixture. （2） From the perspective of the absolute values of the attenuation slopes of tension, compression and bending moduli, the slope of the tension modulus is the largest, followed by the bending modulus, and the slope of tile compression modulus is the smallest. （3） The attenuation ratio of the tension modulus at the critical failure is larger than the attenuation ratio of the compression modulus, that is, the cracking failure of the specimen is not caused by the attenuation of compression modulus, but caused by the rapid attenuation of the tension modulus, which resulting in aggravated damage accumulation in the tension region below the neutral plane. Cracking occurs at first and it is the source of damage to the specimen. （4） In bending fatigue stress state, the decay rules of tension modulus and compression modulus of asphalt mixture are quite different, the decay rate of tension modulus is larger than that of compression modulus, so the damage would be more severe in the tension zone. It is shown that the decay rate of the tension modulus in the stable phase of the modulus decay curve is too fast and the hysteresis of the damage point of the comp

关 键 词：道路工程 疲劳损伤 模量同步测试 岩沥青 模量衰变 

分 类 号：U416.217[交通运输工程—道路与铁道工程]