Study On The Performance Of High Viscosity Warm Mix Asphalt And Its Porous Asphalt Mixture

Porous asphalt pavement has a large porosity and interconnected internal voids,which is a form of pavement that improves the skid resistance of rainy days and reduces driving noise.Due to the use of high viscosity asphalt to ensure the integrity of the asphalt mixture,higher construction temperatures are required to increase energy consumption.At the same time,it is more difficult to control the temperature and time of mixing,paving,and compaction compared to ordinary asphalt pavement.Warm mix technology can reduce the construction temperature and improve the pavement construction performance by certain materials or means.Therefore,the combination of warm mix technology and porous asphalt pavement is considered.In addition the low temperature environment of the project site also presents a great test on the pavement material.This article first uses the response surface method to mix high viscosity asphalt using five materials;Study the influence of two warm mix agents on the basic properties of asphalt through three major indicators and dynamic viscosity;The cloth viscosity was used to evaluate the cooling effect of the warm mix agent,and the mechanism of the two warm mix agents was explored by combining with the Fourier infrared spectrum test to determine the rheology evaluation scale of warm mix asphalt;Analyze the effects of different temperature mixing agents on the high-temperature resistance to rutting,low-temperature resistance to cracking,and deformation of high viscosity asphalt or mortar through experiments such as temperature scanning,frequency scanning,MSCR,BBR,and low-temperature shear relaxation;based on the results of the pre-test,four blends of 2%,4% S,0.3% and 0.5% L warm mixes were selected for the corresponding asphalt mixture tests,and the effect of the two warm mixes on the construction performance was evaluated by the variable temperature compaction test to determine the molding temperature of the asphalt mixture specimens.The effect of warm mix on the mechanical properties of porous asphalt mixture was analyzed by dynamic modulus test;the road performance of warm mix porous asphalt mixture was evaluated by rutting test,freeze-thaw splitting test,fly-away test,low temperature beam test and semicircular bending test.The research results are as follows: 1)The high viscosity asphalt obtained through response surface methodology has excellent high-temperature deformation resistance,low-temperature crack resistance,and fatigue resistance.2)The S-type warm mix agent has a significant impact on the basic properties of asphalt,manifested as a decrease in softening point,an increase in penetration and ductility,and a significant decrease in dynamic viscosity and cloth viscosity;The L-type warm mix agent has a relatively small impact on the three major indicators of asphalt and fabric viscosity,but can significantly reduce the viscosity of asphalt slurry.3)The S-type warm mix agent will reduce the high-temperature deformation resistance and permanent deformation recovery ability of asphalt,but it will significantly improve the low-temperature relaxation performance.Overall,the dosage should not be higher than 4%;L-type warm mix asphalt slurry has good low-temperature relaxation performance,but its creep recovery performance is not as good as the original asphalt.Considering the economy,its dosage should be controlled below 0.5%.4)2%,4% S-type warm mixing agent and 0.3%,0.5% L-type warm mixing agent can reduce the molding temperature by 14.4 ℃,23.8 ℃,15.7 ℃,and 19.7 ℃,respectively.5)Both types of warm mix agents can cause a decrease in the dynamic modulus of porous asphalt mixture,and the degradation effect of S-type warm mix agent is more significant than that of L-type warm mix agent.6)S-type warm mix agent can improve the crack resistance of porous asphalt mixtures,but it has a negative impact on water stability and anti fly performance.The optimal dosage is4%,which is suitable for high altitude areas with high requirements for low-temperature performance;The L-type warm mix agent has a relatively small impact on the performance of porous asphalt mixtures,manifested as a slight decrease in high-temperature performance,while other properties have been slightly improved.The dosage should be 0.5%,so it shows better applicability in the application of porous asphalt mixtures compared to the S-type warm mix agent.