大厚度柔性基层长寿命沥青路面试验研究

Experimental Investigation of Large-thickness Flexible BaseLong-life Asphalt Pavement

为研究大厚度柔性基层沥青路面结构内部力学行为特征及疲劳寿命,以田新高速试验段、主路面结构为原型,分别制作全厚路面结构模型,开展同条件下沥青稳定碎石柔性基层和水泥稳定碎石半刚性基层沥青路面结构静力加载对比试验。采集不同轴载、温度工况下各层位力学响应值,进行变化规律拟合分析,并根据实际工况计算分析疲劳寿命。结果表明,同条件下,沥青稳定碎石柔性基层沥青路面结构下面层底、基层底的横向及纵向应变和竖向压应力指标均明显小于水泥稳定碎石半刚性基层沥青路面结构,且2种结构的下面层底各力学指标均大于其对应基层底指标;2种结构下面层、基层的疲劳寿命对数值随荷载等级增加呈线性下降,前者受温度变化影响更小,且数值均较后者明显提高;正常环境温度和标准交通荷载下,沥青稳定碎石柔性基层大厚度沥青路面结构下面层与基层预期可实现长寿命。研究结果为长寿命沥青路面结构提供新的试验途径与评定方法。

In order to reveal the mechanical behavior characteristics and fatigue life of the structure of large-thickness flexible base asphalt pavement,full-thickness pavement structure models were created based on the prototypes of the test section of Tianxin Expressway and its main road structure,and a comparative test of static loading of asphalt pavement structures with asphalt-stabilized macadam flexible base and cement-stabilized macadam semi-rigid base under the same conditions was carried out.The mechanical response values of each layer under different shaft loads and temperature conditions were collected,the variation law fitting analysis was carried out,and the fatigue life was calculated and analyzed according to the actual working conditions.The analysis results showed that under the same conditions,for the asphalt-stabilized macadam flexible base asphalt pavement structure the lateral strain,longitudinal strain and vertical compressive stress indices of the bottom of the lower surface layer and base layer were significantly smaller than those of the cement-stabilized macadam semi-rigid base asphalt pavement structure.The mechanical indexes of the bottom of the lower surface layer of both structures were greater than those of corresponding the bottom of the base layer.The logarithmic values of the fatigue life of the lower surface layer and the base layer of the two structures decreased linearly with the increase of the load level,and the former was less affected by temperature changes,and the values were significantly higher than the latter.Under normal temperature conditions and traffic loading,the lower surface layer and base layer of the large-thickness asphalt pavement structure with asphalt-stabilized macadam flexible base were expected to achieve long service life.This study provides a new test method and analysis idea for evaluating the structure of long-life asphalt pavement.