不同温度环境下路面沥青混凝土弯曲力学特性试验研究

Experimental Atudy on Bending Mechanical Properties of Asphalt Concrete Pavement under Different Temperature Environment

为研究保定快速公路沥青混凝土在高、低温作用下弯曲力学特性影响变化,采用三点弯曲试验方法开展了不同高、低温物理作用影响下油石比力学试验。试验表明,油石比超过7%后,沥青混凝土抗弯应力受之影响增大,控制油石比不超过7%更利于配合比设计。不论油石比如何变化,沥青混凝土均具有一定残余弯曲应力。高温作用下沥青混凝土抗弯应力最高为100℃,在低于与超过该温度时,抗弯应力分别为递增、递减变化,同时高温热作用愈强,沥青混凝土延塑性变形为主导愈明显。低温冻结力影响下,沥青混凝土在-20℃后抗弯应力增幅减小,温度过低,并不会对试样抗弯应力产生更显著效果。因此,路面沥青混凝土应控制在低温-20℃与高温100℃之间应用,确保其抗弯能力最强。

In order to study the influence of high and low temperature on the bending mechanical properties of Baoding expressway asphalt concrete,the mechanical tests under the influence of asphalt stone ratio,high and low temperature physical action were carried out by using the three-point bending test method.The test shows that the bending stress of asphalt concrete increases when the asphalt stone ratio exceeds 7%,and it is more favorable to control the asphalt stone ratio below 7%for mix design.The research shows that the asphalt concrete has certain residual bending stress no matter how the oil stone ratio changes.The maximum bending stress of asphalt concrete under high temperature is 100℃.When the temperature is lower than or higher than this temperature,the bending stress increases and decreases respectively.At the same time,the stronger the high temperature thermal effect is,the ductility deformation of asphalt concrete is dominant.Under the influence of low-temperature freezing force,the increase of bending stress of asphalt concrete decreases after low temperature(-20℃).If the low temperature is too low,it will not have a more significant effect on the bending stress of the sample.The research shows that the asphalt concrete should be applied at low temperature of-20℃and high temperature of 100℃to ensure the strongest bending resistance.The results of this paper can provide a reference for discussing the bending mechanical characteristics of asphalt concrete and the three-point bending test analysis.