The Experiment Research For Fatigue Performance Of Active Silicon/SBS Composite Modified Asphalt Mixture

At present,there are heavy traffic and large traffic volume in the road operation process,and the requirements for the comprehensive performance of asphalt materials are getting higher and higher.Studying the performance of modified asphalt mixture,in order to improve the comprehensive performance of road asphalt materials to meet the requirements of current road traffic,is an important direction of current road material research.The research on modified asphalt mixtures mostly focuses on polymer modified asphalts,and the research and application range of SBS modified asphalt and rubber asphalt is the most extensive.At present,the modified asphalt mixtures have been most widely studied in depth,so the research on asphalt materials has gradually developed into secondary modified asphalt materials.Researchers have already obtain many excellent properties of composite modified asphalt materials.For the development of asphalt materials,economy has now become an important indicator.Therefore,active silicon has been gradually applied to composite modified asphalt materials as an asphalt modifier with low cost and good performance evaluation as an asphalt modifier.Firstly,the performance of composite modified asphalt prepared by silicon powder with different Si02 content was analyzed by three major experiments.The experimental results show that the high and low temperature of activated silicon/SBS composite modified asphalt are improved with the increase of SiO2 content.The complex shear modulus G*and rutting factorG*/sin? were used as the evaluation indexes of high temperature performance.The creep stiffnessand creep ratewere used as the evaluation indexes of low temperature performance.The rheological properties of composite modified asphalt were studied by DSR and BBR tests.The experimental results show that the high temperature property of the active silicon/SBS composite modified asphalt is effectively improved after the silicon powder is added,and the low temperature performance is affected;the PG classification test results in the composite modified asphalt meeting the requirements of PG70-22,and the high temperature performance.It is superior to SBS modified asphalt,and its low temperature performance is consistent with SBS modified asphalt.Then,using the DSR test instrument for time scanning test and LAS test(frequency scanning and amplitude scanning),it can be seen from the test results that the addition of reactive silicon powder can significantly improve the fatigue life of the composite modified asphalt;The fatigue equation of the asphalt,the parameter A characterizing the fatigue life of the asphalt increases with the addition of silicon powder.Furthermore,through four kinds of fatigue test methods,the four-point bending fatigue test was selected to study the fatigue properties of the active silicon/SBS composite modified asphalt,Nf50 and NfNM the fatigue performance evaluation indexes of the matrix asphalt mixture and the modified asphalt mixture were respectively used.The test results show that the fatigue life value of asphalt mixture increases with the incorporation of reactive silicon powder,that is,the fatigue performance is improved.Finally,the amount of asphalt,SBS contents,silicon powder contents and strain were selected as the influencing factors of fatigue performance of active silicon/SBS composite modified asphalt mixture,and the change trend of fatigue life value with the influence factor was obtained.According to the gray correlation analysis method,the influencing factors are integrated and analyzed,and the result is that the oil-stone ratio is the most affected and the penetration degree is the least.The analysis is influenced by the influence of different factors.