基于弯沉盆变化率的沥青路面弯沉温度修正模型

Deflection Temperature Correction Model for Asphalt Pavement Based on Basin Change Rate

基于FWD检测设备测得的路表弯沉,可以通过模量反演来确定路面结构承载力,从而对路面结构的维修养护提供建议。但由于沥青混合料为温度敏感性材料,其受温度影响较大,温度的变化会引起力学性质的变化,进而影响到结构承载力。因此,建立了基于弯沉盆变化率的沥青路面弯沉温度修正模型。对一条在役高速公路沥青路面在不同季节、不同温度下,进行了路面弯沉测试,反算了沥青层模量,通过对比分析,确定了沥青层代表温度;对完整弯沉盆的温度修正方法进行了研究,确定了精度最高的温度修正模型;对比了“先修正”和“后修正”的计算结果,验证了对完整弯沉盆进行温度修正的可行性。研究结果表明:1/2深度处的温度更适宜作为沥青层的代表温度;采用弯沉变化率得到的弯沉-温度修正拟合结果精度更高;基于“先修正”与“后修正”两种方法得到的面层反演模量具有很好的一致性,为沥青路面反算模量提供了一个新的思路。

Based on the deflections measured by FWD,the pavement structure bearing capacity can be determined by modulus backcalculation,so as to provide suggestions for the maintenance of pavement structure.Asphalt mixture is greatly affected by temperature because it is a kind of temperature-sensitive material.The change of temperature will cause the change of asphalt concrete mechanical properties and then affect the bearing capacity of the structure.Therefore,a temperature correction model of the asphalt pavement deflection was established in this paper based on the change rate of the deflection basin.FWD tests of asphalt pavement in service was carried out under different temperatures in different seasons,the modulus of asphalt layer was backcalculated,and the representative temperature of asphalt layer was determined through comparative analysis.The temperature correction method of complete deflection basin was studied and the temperature correction model with the highest accuracy was determined.The calculation results of’first correction’and’second correction’were compared,and the feasibility of temperature correction for complete deflection basin was verified.The results show that the temperature at 1/2 depth is most suitable as the representative temperature of asphalt layer.The deflection temperature correction fitting result obtained by the deflection change rate is more accurate.The asphalt layer modulus calculated by first modification is in good agreement with that obtained after modification,which provides a new way to backcalculate the modulus of asphalt pavement.