Research On Pavement Performance And Dynamic Response Of Permeable Polyester Fiber Asphalt Mixture And Application

With the rapid development of traffic transportation, the advantages of asphalt pavement, such as smooth surface, comfortable driving, small noise, and no dust, have been played sufficiently. While common asphalt pavement is impermeable, the pavement anti-slide performance will drop sharply in rain or snow days for the water on pavement could not drain in time. And the traffic accidents may happen and the traffic safety will be affected seriously.To improve the traffic safety and comfort, the material composition, pavement performance and dynamic responses of permeable asphalt pavement have been investigated according to the notification of "To do a good job of city drains facilities construction" which is released by General Office of the State Council of the People’s Republic of China. Permeable asphalt pavement is a general term of asphalt pavement which is constructed by asphalt mixture with voidage of 18% to 25%. The water on pavement can go into the road and be drained transversely, or infiltrate into the subgrade inside. Combining theoretical analysis, laboratory test, with field test, permeable asphalt mixture with polyester fiber content of 0,0.3%,0.35%,0.4%, 0.45%, and 0.5% have been investigated from material composition, water stability, high and low temperature performance, compression and tension performance, and dynamic mechanical performance. Moreover, the dynamic responses of permeable polyester fiber asphalt surface layer for tested road have also been monitored when vehicle passing, such as transversal strain, longitudinal strain and vertical pressure. Main conclusions are shown as follows.(1) Passing ratio of key sieves for 2.36mm and 4.75mm in mineral aggregate gradation are significant factors for voidage of permeable asphalt mixture. The passing ratio of 2.36mm key sieve should choose a small value and the passing ratio of 4.75mm key sieve has an optimal value of 15%.(2) Schellenberg binder drainage test results indicate that adding polyester fiber can reduce the leakage loss of permeable asphalt mixture apparently and also lower the probability of asphalt loss. An increase of 0.05% for polyester fiber will lead to an increase of optimal asphalt content. Optimal asphalt content for asphalt mixture with polyester fiber is a little bigger than that without polyester fiber.(3) Influence of polyester fiber on voidage of permeable asphalt mixture has been analyzed. And it is found that adding polyester fiber makes the voidage small. Total voidage and connected voidage present a tendency of first decreasing then increasing with polyester fiber content increasing. And there is a linear relationship between connected voidage and total voidage.(4) Pavement performance tests of permeable polyester fiber asphalt mixture, such as water stability, high and low temperature performance have been conducted. Test results show that adding polyester fiber can improve the water stability, high and low temperature performance, and polyester fiber content has an optimal value of 0.4%. Voidage is an important factor affecting the pavement performance. The bigger the voidage is, the worse the pavement performance is.(5) Compression and tension test results of permeable polyester fiber asphalt mixture demonstrate that the maximum compressive and tensile strength achieve when polyester fiber content is 0.4%. Splitting tensile strength after freeze-thaw is apparently smaller than that before freeze-thaw.(6) Dynamic mechanical characteristics of permeable polyester fiber asphalt mixture have also been investigated. And it is indicated that permeable polyester fiber asphalt mixture is a strain rate sensitive material and an obvious strain rate effect presents. Impact compressive stress-strain curve of permeable asphalt mixture includes elastic deformation stage, plastic deformation stage and failure stage. Dynamic increase factor can reflect the increasing degree of dynamic strength compared with static strength. Under impact load, permeable polyester fiber asphalt mixture shows three failure modes, cracking, broken in blocks, and broken in pieces. The broken of aggregate is the main reason of its failure. Optimal dynamic mechanical performance achieves when polyester fiber content is 0.4%, and it decreases with voidage increasing.(7) Field test results show that the transverse strain, longitudinal strain, and vertical pressure of permeable polyester fiber asphalt surface layer are decreasing with running speed increasing. Heavier vehicle load will cause bigger dynamic responses and larger fatigue damage for permeable polyester fiber asphalt surface layer. The dynamic responses of permeable polyester fiber asphalt surface layer at 22 ℃ are bigger than those at 7 ℃. The dynamic responses of permeable polyester fiber asphalt surface layer are smaller than those of common asphalt surface layer. Field quality testing indicates that permeable polyester fiber asphalt pavement presents smooth surface, good drainage performance and anti-slide performance.