Experimental Research On Drainage Performance Of Multi-Lane Drainage Asphalt Pavement

Drainage asphalt pavement has becoming an important development direction of highway construction due to its excellent performance such as good drainage performance,low noise,anti-slide performance,reduce glare,alleviation of the heat island effect and saving material.Drainage asphalt pavement has large scale pore structure so that rainwater landing to the road surface can rapidly infiltrate into the drainage layer and then discharge through the lateral seepage,this can,on the one hand,decrease mist phenomenon caused by driving in raining environment,then improve the driving visibility and safety in the rain.on the other hand,reduce the water damage due to rainwater cannot be discharged timely and then staying inside the pavement structure.This article studied experimentally the drainage performance of multi-lane drainage asphalt pavement according to the research on drainage function design methods of multi-lane drainage asphalt pavement which belongs to project of highway industry standard revision directed by Ministry of Transport.This article obtains the main aperture sieve passing rate and mixture material pore rate regression equation using the orthogonal test method.Then by studying the relationship between drainage asphalt mixture material pore rate and permeability coefficient,we get to acquire both the relational expression among pore rate,connection pore rate and permeability coefficient,and the empirical formula between vertical/lateral permeability coefficient and connection pore rate.Setup indoor test section according to the proposed pavement design parameters,using rainfall simulation system to simulating different rainfall intensity,then measured the water film thickness value on the road surface and the water drainage time of the drainage layer with different rainfall intensity.Compared the measured values with the theoretical values,the study found that there is a good linear correlation between the measured values and the theoretical values,the correlation coefficient reached more than 0.95,which shows that theoretical calculation can well reflect the drainage asphalt pavement water film produced in the actual situation and verifies the theory of water film thickness calculation formula.Using Abaqus finite element software simulate the drainage asphalt pavement rainfall infiltration,got the simulation thickness value of water film on the road surface under different rainfall intensity,the study found that the simulated values and the theoretical calculation values have obvious linear correlation,and the correlation coefficient reached more than 0.9.Simulated values and calculated values also have the same overall change trend.When the rainfall intensity is small,the values of simulation are lower than the calculated values,but with the increase of rainfall intensity,the simulation results gradually approach the theoretical calculation values and keep the same,even slightly higher than the theoretical values but with the same overall change trend.Verifying the status of water film in drainage asphalt pavement with transverse drainage ditch and drainage asphalt pavement with double drainage structure situation through finite element numerical simulation,simulation results show that 1)relatively dense transverse drainage ditch(space less than 2m)can reduce the thickness of the water film,but if the drainage ditch space is too large(greater than 2m)the effect is not obvious,2)in the same rainfall time,while the thickness of drainage pavement reaches greater than 10cm(i.e.thickness of double drainage structure),the road is not easy to produce runoff.