基于UFAC应力吸收层的抗反射裂缝性能评价
Evaluation of anti-reflective crack resistance based on the UFAC stress-absorbing layer
李智 1童竞1
作者信息
- 1. 华南理工大学 土木与交通学院,广东 广州 510641
- 折叠
摘要
目的 为了解决"白加黑"技术中的反射裂缝问题,针对目前常用的悬浮密实型高弹改性沥青混合料(super flexible asphalt concrete,SFAC)应力吸收层变形量较大、容易造成上部沥青加铺层不利于受力的缺陷,方法 提出基于CAVF法和富沥青理念优化设计的骨架密实型UFAC应力吸收层.采用有限元ABAQUS数值模拟方法对"白加黑"路面结构进行受力分析,并通过加速加载试验、冲击韧性试验和劈裂试验对材料与结构的抗反射裂缝性能进行评价.结果 重载条件下,UFAC应力吸收层和高弹改性沥青应力吸收层的竖向位移相差 5.93×10-2 mm,沥青加铺层底部所受竖向压应力σy、最大主应力σmax、最大剪应力τ12 分别降低24%,32.3%,27.7%.当路面存在严重脱空或常规脱空情况时,基于UFAC应力吸收层的路面结构比GAC加铺路面结构的抗疲劳开裂性能分别提升48%,36%.与传统的悬浮型砂粒式AC-5应力吸收层相比,UFAC-5应力吸收层的冲击韧性增加60.8%,劈裂抗拉强度提高16.8%.结论 基于UFAC应力吸收层的沥青加铺技术,通过增大常规改性沥青膜厚保证必要的疲劳抗拉能力,并采用骨架密实型级配显著提高集料间的嵌挤能力和内摩阻力,减小层间结构变形,可有效减缓沥青加铺层反射裂缝的产生与发展.
Abstract
Objectives To address the issue of reflective cracking in"white and black"pavement technol-ogy,this paper proposes an optimized design for a skeleton-dense UFAC stress-absorbing layer.This de-sign,based on the CAVF method and the concept of rich asphalt,aims to overcome the shortcomings of the commonly used dense-graded super flexible asphalt concrete(SFAC)stress-absorbing layer,which tends to exhibit significant deformation and adversely affect the overlaid asphalt layer.Methods The finite element method using ABAQUS was employed to conduct a stress analysis of the"white and black"pave-ment structure.Additionally,the reflective cracking resistance of the materials and structure was evaluated through accelerated loading tests,impact toughness tests,and splitting tests.Results Under heavy load con-ditions,the vertical displacement difference between the UFAC stress-absorbing layer and the SFAC stress-absorbing layer is 5.93×10-2 mm.Consequently,the vertical compressive stress(σy),maximum principal stress(σmax),and maximum shear stress(τ12)at the bottom of the asphalt overlay are reduced by 24％,32.3％,and 27.7％,respectively.In cases where the pavement has severe or typical voids,the fatigue crack resistance of the asphalt overlay structures based on the UFAC stress-absorbing layer is improved by 48％and 36％,respectively,compared to the GAC overlay pavement structures.Additionally,compared to the traditional dense-graded sand-asphalt AC-5 stress-absorbing layer,the skeleton-dense UFAC-5 stress-absorbing layer exhibits a 60.8％increase in impact toughness and a 16.8％improvement in splitting tensile strength.Conclusions The significant deformation characteristics of SFAC stress-absorbing layers can ad-versely affect the overlaid asphalt layer,leading to reflective cracking and premature pavement damage.The asphalt overlay technology based on the UFAC stress-absorbing layer addresses these issues by increasing the thickness of the conventional modified asphalt film to ensure the necessary fatigue tensile strength.Ad-ditionally,it employs a skeleton-dense gradation to significantly enhance the interlocking capacity and internal friction of the aggregate,reducing interlayer structural deformation.This effectively mitigates the occur-rence and progression of reflective cracks in the asphalt overlay.
关键词
应力吸收层/薄层富沥青混合料/骨架密实型/有限元数值模型/抗压变形Key words
stress-absorbing layer/ultra thin full-asphalt concrete/skeleton-dense/accelerated loading test/fracture mechanical performance引用本文复制引用
出版年
2025
国家科技期刊平台
NSTL
万方数据