Study On Reasonable Viscosity Range Of Porous Asphalt Mixture High Viscosity Asphalt Based On Pavement Performance

Porous asphalt pavement has been widely used at home and abroad because of its excellent function of drainage and noise reduction,but its structural strength and road performance are inferior to other dense asphalt pavement because of its large void ratio.The research shows that the dynamic viscosity of asphalt at 60℃ is a key index that affects the structural strength and road performance of asphalt mixture.The selection of high-viscosity asphalt with reasonable viscosity can make the porous asphalt mixture have good road performance and improve the economic benefits of the project.Therefore,it is of great significance to study the reasonable range of asphalt viscosity.In this thesis,through laboratory tests,from the preparation and performance evaluation of high-viscosity asphalt,the design of porous asphalt mix and the function verification of pavement,the road performance test and evaluation of porous asphalt mix with different viscosity ranges,and the study of the reasonable viscosity range of porous asphalt mix,etc.The relationship between the dynamic viscosity of high viscosity asphalt at 60℃ and the road performance index of porous asphalt mixture is studied,which provides a scientific basis for the reasonable selection of porous asphalt binder.The main research contents and conclusions of this thesis are as follows:1.High viscosity asphalt with different viscosity can be prepared by changing the content of high viscosity agent.HVA and AR-HVA high viscosity agents were combined with SBS modifier to modify 70# matrix asphalt.The modification effects of the two high viscosity agents in various dosage ranges were compared to determine the appropriate type and dosage of high viscosity agents.The test results show that the high-viscosity asphalt prepared by the combination of AR-HVA high-viscosity agent and SBS modifier has better comprehensive performance.Therefore,high-viscosity asphalt with different viscosity is prepared by the combination of AR-HVA high-viscosity agent and SBS modifier for the subsequent porous asphalt mixture test,in which the content of SBS modifier is 2%.The content of AR-HVA high adhesive is 6%,7%,8%,9%,10%.2.The medium grade of PAC-13 was selected to prepare porous asphalt mixture,and the optimal oil-stone ratio corresponding to high-viscosity asphalt with different viscosity was determined through leakage test and flying test.The production and construction temperatures of porous asphalt mixtures with different viscosity were studied by viscosity-temperature curve method and variable temperature compaction method.The results show that the variable temperature compaction method can reasonably reflect the suitable production temperature and construction temperature of porous asphalt mixture.The structural strength and pavement function of the porous asphalt mixture are verified.The test results show that the five kinds of porous asphalt mixture with different viscosity have good drainage and anti-skid properties.The Marshall stability of porous asphalt mixture increases with the increase of dynamic viscosity at 60℃.3.The road performance of porous asphalt mixtures with different viscosity was evaluated through laboratory tests.The test results show that the high temperature stability,water stability and fatigue resistance of porous asphalt mixture are obviously improved with the increase of dynamic viscosity at 60℃,but the low temperature crack resistance is adversely affected.The higher the dynamic viscosity of asphalt at 60℃,the smaller the improvement of the high temperature stability,water stability and fatigue resistance of porous asphalt mixture,and the adverse effect on the low temperature crack resistance is more obvious.4.Considering the construction workability of porous asphalt mixture in different viscosity ranges,the variation trend of various road performance and engineering economic benefits,the reasonable viscosity range of porous asphalt mixture with high viscosity asphalt was studied.The recommended viscosity range of high viscosity asphalt is 3.91×104Pa·s ～32.61×104Pa·s.In this viscosity range,porous asphalt mixture has the best road performance,suitable construction and easy performance,and the highest engineering economic benefit.