Research On Mix Design And Pavement Performances For Special Basalt Fiber Reinforced BRA Modified SMA Mixture

With it's excellent pavement performance,Indonesian Buton Rock Asphalt(BRA)and basalt fiber have gotten more and more attentions.But few studies have incorporated both of them into the asphalt mixture to research the modified and reinforced effect.Thus,the thesis selects SMA-13 as the research object to carry out the research on mix design and pavement performance for special basalt fiber reinforced BRA modified SMA-13 asphalt mixture(BBSMA-13 for short),so as to provide a scientific reference for the popularization and application of new asphalt materials pavement.1)Based on the selection of qualified raw materials and rational aggregate gradation,according to 1%,0.1% and 1% of the interval between 2%~5%,0.2%~0.5%and 4%~7%,each four kinds of BRA contents,special basalt fiber contents and asphalt contents were selected,respectively.The orthogonal table L16(45)was selected to arrange the test combinations in accordance with the orthogonal test method,and the BBSMA-13 asphalt mixture were carried out the Marshall tests.The results show that the BRA content is the key influencing factor of flow value and stability,the special basalt fiber content is the key influencing factor of flow value.When the special basalt fiber content increases from 0.2% to 0.3%,the flow value of BBSMA-13 reduces,but the stability increases.When the content increases from0.3% to 0.5%,the flow value of BBSMA-13 increases,but the stability decreases.Meanwhile,along with the content of BRA increasing,the stability and the air voids increase,but the flow value and the saturation decrease.According to the requirements of each index,the optimal BRA content is 3%,and the optimal special basalt fiber content is 0.3%,which are determined by the comprehensive analysis.2)Under the optimal BRA and special basalt fiber content,the mix ratios of BSSMA-13 mixture were designed by the Marshall tests,and the optimal total asphalt-aggregate ratio(the optimal asphalt-aggregate ratio with matrix asphalt and pure natural asphalt in BRA)was determined as 6.13%,i.e.the optimal practical asphalt-aggregate ratio(the optimal asphalt-aggregate ratio with only matrix asphalt)is 5.42%.In comparison with the optimal asphalt-aggregate ratio 6.03% of ordinarySBS modified SMA-13,although the optimal total asphalt-aggregate ratio of BBSMA-13 increases slightly,the optimal practical asphalt-aggregate ratio decreases significantly,so it shows that the BRA can effectively replace the partial matrix asphalt.By the Cantabro scattering loss and Schellenberg binder drainage tests,the results show that the designed mix ratio of BBSMA-13 mixture has no excess asphalt,and the binder drainage loss is small,which shows that the designed mix ratio is reasonable and feasible.3)Through the comparative analysis of pavement performance tests,the results show that the pavement performances of BBSMA-13,including high temperature stability,water stability,anti permeability and anti slip,are increased,but the low temperature crack resistance decreases slightly in comparation to the ordinary SBS modified SMA-13.It shows that the incorporation of BRA and special basalt fiber can be very good to improve the pavement performances of SMA-13 and suitable for hot and humid areas in the South.4)Compared to the economic benefits of two different SMA-13 under the designed mixture ratios,it was found that the BBSMA-13 with the optimal BRA and special basalt fiber content has better economy,and it is worth popularizing and applying.To sum up,in the asphalt mixture SMA-13 and incorporation of BRA and special basalt fiber can effectively improve the pavement performances with higher economic benefits.The proposed designed mix ratio is reasonable and feasible,it provide a reference for the engineering applications.