不同空气压力下沥青混凝土的透水性能

Research on Permeability Performance of Asphalt Concrete under Different Air Pressures

对我国常用沥青混合料进行对比,发现在压实后其空隙率远高于设计值,使刚建成的沥青路面存在透水的风险,从而引起路面水损坏的发生。提出了沥青混合料空隙层次模型,并通过不同空气压力下沥青混合料的透水性能试验进行验证,结果表明:上述模型是合理的,常压下沥青混凝土的吸水率要小于其空隙率,而正压下的吸水率与常压吸水率基本相同;交替压力下的吸水率与真空吸水率相似,均高于常压吸水率,说明真空压力是促使沥青混凝土吸水的主要原因。

The commonly used asphalt mixtures in China are compared, it is found that the air voids of asphalt pavement after compaction is far larger than the design value, which makes the new asphalt pavement easy to be permeated and then causes the water damage of pavement structure. The layered void model of asphalt mixture is assumed, which is verified through the permeability performance tests under different air pressures. The results show that （1） the proposed model is reasonable because the water absorption of asphalt mixture under ordinary pressure is less than the air voids, and the water absorption under ordinary pressure is equal to the value under positive pressure; （2） the water absorptions under vacuum pressure and alternative pressure are similar, both of them are greater than the value under ordinary pressure, which shows that the vacuum pressure is the main reason of the water absorbency of asphalt mixture.