Research On The Properties Of High Modulus Asphalt Prepared Based On Hard Asphalt And SBS Modified Asphalt Respectively

As China's economic and social development enters a new era,the requirement of high-quality infrastructure development drives the continuous development of long-life asphalt pavement construction technology,and the high modulus asphalt mixture with excellent overall performance becomes one of the core of long-life asphalt pavement technology.At present,the design of high modulus asphalt mixtures and the production of key asphalt binders in China have not yet formed a unified standard,especially the production technology of high modulus asphalt with stable performance has become the key to restrict the large-scale application of high modulus asphalt mixtures.Based on this,this paper investigates the technical path and methods to achieve high performance of high modulus asphalt based on the basic principles of asphalt binder toughness enhancement;to prepare high modulus asphalt binder for engineering applications by preferably selecting basic asphalt materials and modified materials;to evaluate the performance of high modulus asphalt and corresponding mixes through asphalt conventional performance test,asphalt rheological test and mix performance test;to evaluate the performance of high modulus asphalt and corresponding mixes through asphalt pneumatic rebound test Research to determine the quality of high modulus asphalt rapid testing and evaluation techniques and indicators.The main research results are as follows:(1)Two technical paths and methods for the preparation of high modulus asphalt were identified,namely,upgrading the modulus gradient first and optimizing the performance later,and optimizing the overall performance of asphalt binder first and improving the modulus later;based on the two technical paths,high modulus asphalt was prepared by using No.20 hard asphalt as the base material and SBR(rubber powder /latex)as the modified material,and SBS modified asphalt as the base material and CON-II high modulus agent as the modified material.(2)The study determined that based on the above two technical paths can achieve excellent performance in the preparation of high modulus asphalt,analyzed the changes in the high and low temperature performance index of modified asphalt under different modifier dosing,and determined the best modifier dosing to meet the performance index of high modulus asphalt.The results show that: with the increase of modifier dosage,the high temperature performance of modified asphalt are effectively improved,but the low temperature performance of asphalt binder is improved differently,the low temperature performance of asphalt is optimized with the increase of SBR modifier dosage,while the low temperature performance of CON-II high modulus agent is significantly deteriorated with the increase of dosage.By studying the performance index of high modulus asphalt,the preparation formulations of high modulus asphalt under two technical paths were determined: when No.20 hard asphalt was selected as the base material,the dose of SBR latex was 4%;when SBS modified asphalt was used as the base material,the dose of CON-II high modulus agent was 18%,and the prepared modified asphalt could meet the performance index requirements of high modulus modified asphalt.(3)Using asphalt pneumatic rebound test system,a rapid evaluation technique of high modulus asphalt quality was established to verify the performance of high modulus asphalt prepared based on two different technical paths.The results show that: the asphalt pneumatic rebound test can achieve rapid evaluation of high modulus asphalt by analyzing and screening the rebound rate and creep deformation of asphalt;the maximum creep deformation of asphalt and rebound rate of high modulus modified asphalt performance of rapid analysis shows that the high modulus asphalt prepared by the two process formulations meet the requirements of PG82-22 grade.(4)The road and mechanical properties of the high modulus asphalt mixes prepared by the two technical routes were analyzed and evaluated.The results show that: the performance test results of high modulus asphalt mixes under both paths can meet the performance index requirements of high modulus asphalt mixes;the fatigue performance of SBR latex modified hard asphalt mixes is significantly improved compared with the road performance of finished high modulus asphalt mixes;the low temperature crack resistance and dynamic modulus of CON-II high modulus agent modified SBS asphalt mixes are significantly improved.