Study On Gradation Optimization Of Porous Asphalt Mixture Based On The Discrete Element Method

Porous Asphalt Pavement is made up of the open-graded asphalt mixture by alarge number of single-size gravel in accordance with skeleton-compact principle toform the stone on stone contact which has anti-slid and low-noise function ,thusgreatly improve traffic safety, especially driving security against sliding in wetweather. With the rapid development of economy and society, people pay moreattention to traffic safety, comfort and the impact on the surrounding environment.Therefore, the drainage asphalt pavement applies to many highways in rain region andhas great promotional prospects in china.Take into account the composition of Mineral aggregate in the drainage asphaltmixture, the quality characteristics of the coarse aggregate has an important impact onthe drainage asphalt mixture performance, and the degree of influence is much largerthan the dense-graded asphalt concrete, therefore, the quality requirement of coarseaggregate in porous asphalt mixture is much more than dense-graded asphalt concrete.At present, the quality requirement of coarse aggregate mostly refer to the standard ofdense-graded asphalt concrete or SMA. To this end, we build gradation of mineralaggregate numerical experiments based on particle flow code in two dimensions andconduct mineral aggregate numerical experiments on two structures PA-13 and AC-13of the asphalt pavement surface layer, analyzed the two structures graded mineralaggregate micro contact state, on this basis, the aggregate crushing value standard ofthe porous asphalt mixture is recommended.The composition of coarse aggregate and fine aggregate decide to form askeleton-gap structure, and the stability of skeleton structure has an importantinfluence on the performance of the porous asphalt mixture. The paper drafted threekinds of gradation to study different passing rates of 9.5mm on the stability of mineralaggregate skeleton structure. Conducted numerical test study on three representativegradations of mineral aggregate, starting from the micro contact force of mineralaggregate under load to analyze the distribution of micro contact force and the size ofmicro contact force, and putted forward the preferred gradation, and verified throughlaboratory test.The paper study on the micro contact force status of the drainage asphaltpavement mineral mixture under load from the micromechanics point of view. On thebasis, the recommended standard of coarse aggregate crushing value and preferred gradation are putted forward, enlightening to the performance of the drainage asphaltpavement.