Study On Performance Of Basalt Fiber/Rock Asphalt Composite Modified Asphalt

With the gradual deepening of highway construction,higher requirements are put forward on the performance of asphalt pavement.Adding modifiers into the asphalt,which can modify the asphalt and improve its corresponding performance,has become a hot topic for researchers.In road engineering,polymer-modified asphalt led by SBS modified asphalt is widely used.However,due to the relatively expensive polymer and poor compatibility with asphalt,the preparation process of SBS modified asphalt is strict.Rock asphalt is a kind of natural asphalt,which is the same as petroleum asphalt.They have good compatibility,and rock asphalt can obviously improve the high-temperature performance of asphalt,but weaken the low-temperature performance.Basalt fiber is one of the green building materials prepared by basalt minerals through a series of processes such as high-temperature smelting,molding,and grinding.Basalt fiber can effectively improve the low-temperature performance of asphalt.Therefore,these two materials are used to modify the asphalt to improve the high and low temperature performance of the asphalt.For these two materials,the price is low.and the preparation is relatively simple.Firstly,the research studied the preparation process of compound modified asphalt,mixing rate and time,shear rate and time,and swelling time.The best preparation process was determined through the three major indexes of asphalt.Secondly,DSR test and BBR test are carried out on composite modified asphalt,and "G*/sinδ"and "S","m" are used as indexes to evaluate the high and low temperature performance of composite modified asphalt.Finally,according to the data of DSR test and BBR test,the "TLH and TLC" of compound modified asphalt is calculated by formula interpolation,which further quantify the performance of composite modified asphalt.Through the applicable temperature range,the optimal dosage of the two modifiers is determined.The research results show that the basalt fiber/rock asphalt composite modified asphalt has excellent high and low temperature performance which is prepared under the best preparation process.After adding rock asphalt into the base asphalt,both TLH and TLC of the asphalt increase.Among them,after mixing 2wt%,4wt%,6wt%,8wt%rock asphalt into the asphalt.TLH can increase 4.21℃,6.05℃,7.29℃,9.36℃,respectively.It shows that rock asphalt can improve the high temperature performance of asphalt very well.However.the TLC of asphalt will also increase by 2.08℃.4.94℃,8.18℃,11.35℃,which means that rock asphalt will obviously weaken the low temperature performance;After adding basalt fiber into the base asphalt.asphalt TLH has increased,but TLC has decreased significantly.Among them,after mixing 2wt%.4wt%.6wt%,8wt%basalt fiber into the asphalt,TLH can increase 3.11℃,2.79℃,3.12℃,2.87℃,respectively,indicating that basalt fiber does not significantly improve the high temperature performance of asphalt.However,the TLC of asphalt can drop 2.84℃,3.76℃,4.87℃,5.43℃,respectively,meaning that basalt fiber can improve the low-temperature performance of asphalt.According to the TLH and TLC of the composite modified asphalt,the applicable temperature range of the composite modified asphalt can be known.Adding 6wt%basalt fiber and 4wt%Iranian rock asphalt into the base asphalt,the high temperature applicable temperature can reach 73.2℃ as well as the low temperature applicable temperature can reach-17.48℃.The design applicable temperature range is 90.68℃,which is the largest.The composite modified asphalt has the best high and low temperature comprehensive performance.