开级配大粒径沥青碎石防裂层沥青路面应力与抗裂机理数值分析

1.陕西交通职业技术学院 公路工程系,陕西 西安 710018; 2.长安大学 公路学院,陕西 西安 710064; 3.长安大学 材料学院,陕西 西安 710064

道路工程; 开级配大粒径沥青碎石; 三维有限元; 应力分析; 抗裂机理; 裂缝缓解层

Numerical analysis on stress and anti-cracking mechanism of open-graded large stone asphalt mixes cracking relief layer in asphalt pavement
GUO Hong-bing1,2,ZHAO Ya-lan1,2,CHEN Shuan-fa3

(1.Department of Highway Engineering,Shaanxi College of Communication and Technology,Xi'an 710018,China; 2.School of Highway,Chang'an University,Xi'an 710064,China; 3.School of Material Science and Engineering,Chang'an University,Xi'an 710064,China)

road engineering; open-graded large stone asphalt mixes; three-dimensional finite element; stress analysis; anti-cracking mechanism; cracking relief layer

DOI: 10.13800/j.cnki.xakjdxxb.2015.0121

备注

反射裂缝是半刚性基层沥青路面和刚性基层沥青路面的主要病害之一,针对这一问题,提出了采用开级配大粒径沥青碎石混合料作为裂缝缓解层的方法,利用其大粒径矿料多、沥青含量少及空隙率大的结构特点消散及吸收裂缝处路面应力。以国内外OLSM参考级配为基础,结合试验段修筑情况,采用有限元方法,建立设置OLSM-25裂缝缓解层的沥青路面三维有限元模型,对设置不同类型裂缝缓解层、1#~3#级配OLSM-25裂缝缓解层的沥青路面结构进行热-荷载耦合应力对比分析,从宏观力学响应方面阐释了OLSM-25裂缝缓解层的抗裂机理。结果 表明:与相同厚度的普通AC-25裂缝缓解层相比,OLSM-25裂缝缓解层的温度敏感性相对较小,具有较高的承载能力和良好的应力消减及缓解性能; 在相同的外部荷载作用下,随着1#~3#级配OLSM-25空隙率的增大,以及抗压回弹模量和线膨胀系数的降低,其自身的车辆荷载应力、温度应力、耦合应力呈总体降低趋势。在实际工程应用中,仅从缓解应力效果及抗裂性能方面考虑,选择级配偏粗、空隙率较大的3#级配OLSM-25作为裂缝缓解层效果较好,但应严格控制施工中的离析问题。

The reflective cracking is one of the main damages of semi-rigid base asphalt pavement and rigid base asphalt pavement.Aiming at this problem,a method of using Open-graded Large Stone asphalt Mixes(OLSM)as the cracking relief layer is proposed,large mineral aggregate,low asphalt content and great porosity can dissipate or absorb stresses and strain around the crack.The three-dimensional finite element model of asphalt pavement structure with OLSM-25 cracking relief layer is established by the finite element method according to the reference gradation of OLSM both at home and abroad and the condition of construction in the test roads.After comparative analyzing on the temperature-load coupling stress in asphalt pavement structure with different types of cracking relief layer and 1#~3# gradation OLSM-25 cracking relief layer, illustrate the anti-cracking mechanism of OLSM-25 cracking relief layer from the aspects of macro mechanical response.The results show that compared to the ordinary AC-25 cracking relief layer with the same thickness,the temperature sensitivity of OLSM-25 cracking relief layer is relatively low and it has higher carrying capacity and better stress relief performance than that of ordinary AC-25 cracking relief layer.Under the action of the same external load,the vehicle load stress,temperature stress and coupled stress of OLSM-25 cracking relief layer show overall decreasing trend with its increasing porosity,decreasing compression modulus and coefficient of linear expansion.In practical engineering applications,it is better to choose 3# gradation OLSM-25 with more coarse gradation and greater porosity as the cracking relief layer,but we should pay more attention to the problem of segregation and control it strictly in construction.