Study On The Properties Of Low Rolling Resistance Modified Asphalt Mixture

In the process of driving,rolling resistance will be generated due to the contact between the wheels and the running road,and the vehicle energy consumption will increase with the increasing of rolling resistance,thus consuming more oil and producing more pollution.At present,the research on rolling resistance is focused on the field of automobile tires.Researchers reduce the strain hysteresis of rubber tire materials to reduce the dynamic heat generation of tires during driving.In this study,the tanδ,a key technical indicator used in the tire industry to measure the energy consumption of automobiles during driving,was introduced into the research field of road materials to characterize the internal heat generation of asphalt materials under external load and the resistance of asphalt materials to external deformation.In this study,we independently developed an HPT modifier which can significantly reduce the loss factor of asphalt materials,and studied its influence on the viscoelastic energy and resistance to permanent deformation of asphalt materials,as well as its influence on the road performance and mechanical properties of asphalt mixture.Firstly,on the premise of the preparation of HPT composite modified asphalt,the influence of modifier on pavement performance,viscoelastic energy and rheological properties of asphalt material was compared and analyzed.Results: compared with the original SBS modified asphalt,the phase Angle and loss factor of low roll resistance composite modified asphalt will decrease with the increase of temperature or the decrease of loading frequency.Low rolling resistance modifier can make the viscosity of asphalt material’s loss modulus growth rate is reduced,the storage modulus of the elastic modulus as far as possible remain the same or lower the attenuation rate,make the storage modulus of asphalt at high temperatures increase compared with the same proportion of asphalt,the loss modulus ratio decreases,and significantly reduced under the condition of high temperature produce permanent deformation of asphalt material,improve the high temperature properties and deformation recovery ability.Based on the principle of reducing loss factor by 20% and not losing other properties,the optimal content of low roll resistance modifier was determined to be 1.5%.Secondly,according to the structural characteristics of asphalt pavement surface and the production and application of asphalt mixture with low roll resistance,two types of SMA-13 and AC-20 are selected in this study.On the basis of determining the gradation suitable for low roll resistance modified asphalt mixture,the influence of low roll resistance modifier on road performance of asphalt mixture was analyzed and compared.The experimental results show that the addition of low roll resistance modifier can significantly improve the high stability of the mixture and increase the dynamic stability by about 50%;The water stability of the mixture was improved by increasing the adhesion between asphalt and aggregate;By increasing the ratio of elastic modulus in asphalt and increasing the ratio of elastic modulus in asphalt,the reversion deformation can be achieved,and the energy dissipation of the mixture under repeated load can be reduced,so that the mixture has better fatigue resistance.However,the incorporation of low roll resistance modifier will also make the mixture lose part of its low-temperature performance,which will make the low-temperature anti-cracking performance of the composite modified asphalt mixture worse.Therefore,the application prospect of SBS-HPT composite modified asphalt mixture is wide in the area with high vehicle flow at high temperature.Finally,by comparing and analyzing the dynamic modulus,phase Angle and other index results obtained from the mechanical properties test of the mixture,the equation of fitting the corresponding dynamic modulus and the main curve of phase Angle can be obtained:The low roll resistance modifier can improve the dynamic modulus of the mixture at high temperature and low frequency and significantly reduce the phase Angle of the mixture on the basis of not losing the low temperature performance of the mixture at low temperature and high frequency.Established a low rolling resistance of modified asphalt mixture loss factor and low rolling resistance and the connection between the modified asphalt loss factor,also proved that the low rolling modifier can make the material more external load resistance,reduce material modification effects of permanent deformation.