全温域条件下沥青路面永久变形预估方法

为了准确、快速预估沥青路面沥青层永久变形,以江西省泉南高速吉莲段为试验路段,从全温域角度出发,引入分区分级分层的思想,即温度分区、轴载分级、路面分层,建立了全温域条件下基于叠加原理的沥青路面永久变形预估方法.通过实测及模型计算得到沥青路面全年温度分布、沥青层沿深度的温度分布曲线和全年轴载分布.根据三轴重复荷载试验建立了SMA-13、AC-20、AC-25三种沥青混合料永久应变黏弹性力学修正模型,确定了不同温度区间的平均修正系数,可求解不同温度和偏应力下不同荷载作用次数的沥青混合料永久应变.通过原点增长累积和反算累积叠加两种方法计算得到设计年限内沥青路面沥青层的永久变形.计算结果表明,泉南高速吉莲段按原点法和反算法的容许永久变形使用年限分别为6年和12年。反算法准确度更可靠,更贴合实际。同时,提出了全温域条件下基于叠加原理的沥青路面永久变形预估修正模型,并建立了基于全温域温度分布的沥青路面温度区间内的平均永久变形量与荷载作用次数关系方程和永久变形与温度区间内的平均永久变形量、温度分布频率的关系方程,为全温域条件下沥青路面永久变形快速预估提供一种新方式.

Prediction method of permanent deformation of asphalt pavement under full temperature conditions

In order to predict the asphalt pavement permanent deformation accurately and quickly, a prediction method of asphalt pavement permanent deformation based on superposition principle is established under full temperature domain. In this prediction method, taking Quanzhou-Nanning Highway of Ji-lian in Jiangxi province as the test section, from the point of view of the full temperature field, the idea of zoning classification layering is introduced, that is, temperature zoning, axle load classification, pavement layering. The annual temperature distribution of asphalt pavement, the temperature distribution curve along the depth of asphalt pavement and the annual axle load distribution are obtained by actual measurement and model calculation. According to triaxial load tests, the three kinds of asphalt mixture (SMA-13, AC-20, AC-25) permanent strain viscoelastic mechanics correction model is established, and the average correction factor of different temperature range is determined, which can be used to calculate the permanent strain of asphalt mixture under different temperature and different deviatoric stress. The permanent deformation of asphalt pavement surface is calculated by two methods of the origin growth accumulation and the counter calculating cumulative superposition. The calculation results show that the allowable permanent deformation life of Quanzhou-Nanning Highway of Jilian section is 6 years and 12 years, respectively, by the origin method and the counter calculating method. The counter calculating method is more accurate and closer to reality. At the same time, a new modified model for predicting permanent deformation of asphalt pavement based on superposition principle is proposed under the condition of full temperature range. The relation equation between the number of loads and average permanent deformation in temperature range of asphalt pavement and the relation equation among permanent deformation, average permanent deformation in temperature range and temperature distribution frequency are established based on temperature distribution in the full temperature range, which provides a new method of rapid prediction of permanent deformation of asphalt pavement under full temperature conditons.