Application Research On Durable High Modulus Asphalt Mixture Design Using Hard Paving Bitumen

Improving the modulus of asphalt mixture can get better traffic loading capacity performance,superior resistance to permanent deformation.While the extremely pursuit of compression modulus of asphalt mixture will lead us to ignore or loose the durability and fatigue resistance of asphalt mixture itself.French EME2 mixes produced by using hard paving grade bitumen(penetration less than 25(0.1mm))at a high binder content,are characterised by high stiffness,excellent fatigue resistance,and offers the prospect of reduced asphalt thicknesses.Due to there were few applications and industrial product(before 2012)of hard paving grade bitumen(HPGB)on pavement engineering in China,this paper draws on the design concept of French high modulus asphalt mixture(EME2),and focuses on the experimental research on the design method of improving the durability of high modulus asphalt mixture(HMAC).Firstly,the HPGB produced by solvent process from Xinjiang(penetration 15 to 25(0.1mm))was tested and compared with the compound blending HPGB.The analysis shows that,both two kind of bituminous have excellent high temperature performance,the performance grade achieves PG82,but the solvent process HPGB has better low-temperature performance.With the help of the Aggregate Imaging System(AIMS),the difference between Xinjiang basalt aggregate and Jiangsu limestone aggregate was analyzed,then the feasibility was preliminarily verified by using Xinjiang basalt aggregate and solvent process HPGB,to design and produce the high modulus asphalt mixture.In the process of mixture design,experimental studies have been carried out on the aspects of air void and aggregate blending selection based on modulus index in this paper.Mixtures’ comprehensive performance(including high and low temperature,anti-fatigue performance)have also been evaluated,the design and performance evaluation indicators for HMAC using Xinjiang basalt aggregate and HPGB are presented initially.The results of the implementation of the test road and performance observation showes that,compared with using compound blending HPGB and limestone aggregates,HMAC produced with the solvent process HPGB and the basalt aggregate of Xinjiang has superior high temperature stability,meanwhile the low temperature properties decays little even after aging condition.The modulus indicator can meet EME2 requirements,although the fatigue resistance is slightly insufficient,it is also suitable for semi-rigid asphalt pavement structures.Compared with the conventional ones,pavement structure using the HMAC can effectively reduce its deflection,improve the bearing capacity and anti-rutting ability.Finally,the technical and economic analysis shows that,It can significantly improve the anti-permanent deformation ability of asphalt pavements without increasing the cost.The research results in this paper provide an effective technical approach for solving rutting and early damage problems accured in Xinjiang in recent years,it can also provide reference for the design of HMAC and the rational application of HPGB in domestic pavement engineering.