Research On Mix Design And Pavement Performances For TLA Modified SMA Asphalt Mixture

Stone Matrix Asphalt(SMA)is widely used in pavement engineering,because of its excellent pavement performance.At the same time,the Trinidad Lake Asphalt(TLA)has been more and more attended as a high cost performance of natural asphalt.Therefore,this thesis selects SMA-13 as the research object to carry out the mix design and pavement performance of TLA modified SMA asphalt mixture,in order to provide a new pavement material for asphalt concrete pavement engineering.1)The conclusion was that every technique index from the testing results of raw materials,such as matrix asphalt and SBS modified asphalt and TLA meet standard requirements.The performances of TLA modified asphalt with different TLA mixing amount was tested and based on the comprehensive analysis of their high temperature performance,low temperature performance and aging performance,the results show that the optimal amount of TLA was 20%~40%.2)The selected three kinds of gradation S1,S2 and S3(key sieve passing rate of 2.36 mm were 17%,20% and 23%,respectively)were tested by using the Marshall test method,and the mixture were measured and calculated by the method of Saturated Surface Dry.The results show that the volume index of S2 meet the requirements,but S1 does not meet the design requirements of VV,and S3 does not meet the design requirements of VMA.So,the S2 is used as the target gradation to carry on mix design on the conventional SBS modified SMA-13 and TLA modified SMA-13 asphalt mixture(TSMA-13 for short).And find that the optimal total asphalt aggregate ratio of the conventional SBS modified SMA-13 is 6.06%,and when the TLA mixing amount was 25%,33.3% and 40%,the optimal total asphalt aggregate ratios are 6.48%,6.83% and 7.24% by the Marshall test method,respectively.According to the results,the optimal asphalt aggregate ratio of the TLA modified asphalt mixture increases with the increasing of the TLA amount.3)Based on the results of the target mixture ratio design,the tests of pavement performances were carried out.And the results show that the target mix ratios of TSMA-13 under each TLA amount are satisfied with the technical requirement of the modified asphalt mixture.And the high temperature stability and water stability about TLA mixing amount of TSMA-13 has obvious improved than conventional SBS modified SMA-13.Water permeability coefficient and texture depth test data show that the results conform to the specification requirements,but the low temperature crack resistance is reducing with increasing of TLA mixing amount;With the optimal asphalt content of the different TLA mixing amount of TSMA-13,when the mixing amount of TLA is increasing,the value of binder drainage test decreases,at the same time,the value of Cantabro test decreasing.4)The direct economic benefit and social benefit of conventional SBS modified SMA-13 and three kinds of TSMA-13 asphalt mixture were analyzed.The results show that when the TLA mixing amount is 25% or 33.3%,TLA modified asphalt has better economy and broad application prospects.In short,the research on mix design and pavement performances for TLA modified SMA asphalt mixture is reasonable and feasible,and the results can provide reference for the further application of TLA.