Rutting Control Technology Of Asphalt Overlay On Rigid Pavement In Moist Heat Areas

In this article,the study focus on rutting problem of asphalt overlay on rigid pavement in moist heat areas.Based on practical engineerings of Fujian province,through field loading test,the laboratory tests,numerical simulation and theoretical analysis.The thesis focuses on the mechanical response of the asphalt overlay on rigid pavement under the dynamic load,microscopic fabric of the surface asphalt concrete and study the prevention method of rutting.Specific results are as follows:Firstly,through the field loading test,to obtain the actual mechanical response of structure under dynamic loads.The analysis showed,the longitudinal dynamic strain and pressure stress of the bottom of the asphalt layer present the greater tension and pressure fluctuation alternating response process.When the speed from 10km/h increased to 30km/h,the longitudinal strain and compressive stress increases by 200%.Under the similar test conditions,the stress and strain of the asphalt overlay on rigid pavement is several times the amplitude of the semi-rigid base asphalt pavement.Simulation the mechanical response of pavement by three-dimensional dynamic finite element model under the moving constant load,and aslo analysis the effect of the different temperature,structure,velosity,axle load and thickness of additional layer.The result of simulation showed,the shear stress of the dynamic load shows a significant change of tension and compression,while under static load,the shear stress does not show a continuous change of tension and compression.The stress of the asphalt overlay on rigid pavement is two times the semi-rigid base asphalt pavement.The vertical strain and vertical shear strain increase by about 40%when the pavement temperature rises 10?,the shear strength and modulus of asphalt concrete decreased with incresing temperature.Therefore,it can accelerate the formation of the rutting under the high temperature,heavy load and low speed.Based on the discrete element method,the rutting research of asphalt overlay structure finds that rut is formed in the asphalt surface.when load is applied on pavement,displacement of aggregate and asphalt is large.The explanation of rut is compaction deformation.Under continuous load,the asphalt mixture shear failure due to the sustained increase tensile and compressive stress,Thereby generating a large displacement.When the temperature exceeded 60?,the amount of pavement rutting increase rapidly,the rutting of the 68? was 2.6 times the amount of 48?,high temperature is an important factor in the formation of the rutting.Compared with the finite element analysis,the composite material can be found in the analysis of displacement aggregates and asphalt,as well as changes in the contact force between the materials.Based on the temperature field properties of asphalt overlay structure,the rutting can be prevented by reducing the pavement temperature.Firstly the mix proportion of the two kind material were designed,then the cooling and heat resistance effect test were carried out by the indoor simulating radiation system,and it was determined that the optimum volume concentration of the TiO2 and the optimum dosage of the ceramic.Research shows that the heat-reflective coatings and ceramic thermal resistance wearing course have obvious cooling effect,the maximum cooling rate of heat reflective coating and thermal resistance wearing course is 9.2 ? and 6?.Wherein,the wear resistance and the high temperature stability is the key.Through the test road construction of the heat-reflective coatings and ceramic thermal resistance wearing course,the construction technology and method of the two kind structures were summarized.It was tracked that the cooling performance,anti-sliding performance and service life of the test road.Results showed that,they have well cooling effect and pavement performance in the real environment,and the anti-sliding performance satisfy the requirement of road.Comprehensive research showed that,pavement analysis should consider moving the load characteristics of the vehicle,choose the appropriate layer thickness of asphalt overlay structure,improve the speed,limit axle load and reduce temperature can reduce the stress-strain response of pavement.Based on the thermal resistance and cooling technology,the heat-reflective coatings and ceramic thermal resistance wearing course can significantly reduce the temperature of pavement,thereby preventing the generation of high temperature rutting,they can provide the rutting control technology for the asphalt overlay on rigid pavement in moist heat areas.