Study On The Performance And Odor-Purifying Mechanism Of Deodorized Asphalt

SBS-modified asphalt has been widely used in pavement projects because of its good road performance.When asphalt is heated,a lot of fumes are generated,which affects human health and the environment.To weaken the bad odor of asphalt,reduce environmental pollution from asphalt pavement construction,and further protect the health of site workers,three odor-purifying agents were blended into SBS-modified asphalt at 0.1wt%,and then three kind of deodorized asphalt were prepared.Firstly,the odor rating of asphalt fumes was evaluated,the solid particle mass of asphalt fumes was collected and measured,the odor gas composition of asphalt fumes was analyzed,the concentration and changes of volatile organic compounds(VOCs)were tested when asphalt was heated.The odor purifying effect of odor purifying agents on asphalt was evaluated.Secondly,to investigate the mechanism of odor elimination,the effect of odor elimination agent on the microscopic surface morphology,internal structure,composition and molecular weight distribution of asphalt was analyzed by Scanning electron microscopy test,Fluorescence microscopy test,Fourier transform infrared spectroscopy test and Gel permeation chromatography test.Then,the physical properties,anti-aging properties and high temperature rheological properties of asphalt were tested to investigate the effects of odor-purifying agents on asphalt properties.Finally,the odor-cleaning effect and performance of three deodorized asphalts were analyzed,and the best deodorized asphalt was determined.The road performance of the deodorized asphalt mixture was evaluated by rutting test,water immersion Marshall test,freeze-thaw splitting test and low temperature bending test.The test results showed that the odor-purifying agents mixed into asphalt showed significant odor-cleaning effect,and the odor-purifying agents reduced the odor level of asphalt,decreased the content of solid particles in asphalt smoke,and reduced the concentration of VOCs when asphalt was heated.The odor-purifying agents reduced the smoke composition of asphalt by more than70% compared with SBS asphalt,which greatly reduced the content of odor gases,and the odor-purifying agents reduced the odor when asphalt was heated.The microscopic test results show that the incorporation of net odorant increases the microscopic surface roughness of asphalt and changed the microscopic structure and composition.The macromolecular content of net odorant asphalt increased compared with SBS asphalt and the small molecule content decreased.The odor-purifying agents improves the molecular and structural stability of asphalt by combining with asphalt molecules into macromolecules and promoting the swelling level of SBS in asphalt,which reduces the internal components of asphalt when heated,decomposition and volatilization of the internal components of the asphalt during heating,and inhibit the generation of malodorous gas emissions.Asphalt performance research showed that the odor-purifying agents increases the viscosity and softening point of asphalt,reduced the needle penetration and ductility of asphalt.Deodorized asphalt had good elastic recovery and aging resistance,and its resistance to deformation and creep recovery ability than SBS asphalt.The high temperature rutting resistance and water damage resistance of the best deodorized asphalt mixture were better than SBS asphalt,and the low temperature deformation resistance and crack resistance were reduced compared with SBS asphalt.In general,the odor-cleaning effect of odor-purifying agents on asphalt was obvious,and it combined with asphalt molecules to form stable macromolecules,enhancing the internal composition and structural thermal stability of asphalt.The level of decomposition and volatilization of deodorized asphalt decreased when heated,and the reaction of asphalt molecules to generate new substances was less likely to escape,the odor gas emission was reduced,and the irritation of asphalt fumes to humans and pollution of the environment was weakened.The deodorized asphalt has both deodorizing effect and good mechanical and road performance,which has environmental significance.