| Asphalt pavement has been widely used in the road construction of our country because of its good performance and easy maintenance.However,due to the combined effects of geography,climate and vehicle load,asphalt pavement appeared all kinds of rut,crack,pit and other diseases during its serviceable period.These diseases greatly reduce the quality and performance of asphalt pavement.In the early highway disease survey of our country,it is found that the poor combination of asphalt and aggregate is the most fundamental cause of the disease.Therefore,it is of great significance to improve the pavement performance of asphalt mixture and prevent the early destruction of pavement by selecting the best asphalt and aggregate with good adhesion and matching.In this paper,the matching between asphalt and aggregate is studied from the point of view of adhesion between asphalt and aggregate and the water stability of asphalt mixture.Based on the analysis of the theory and evaluation methods of asphalt aggregate adhesion at home and abroad,trying to use the theory of surface free energy to study the adhesion mechanism between asphalt and aggregate.According to the theory of surface energy,the calculation model of surface free energy change of asphalt-aggregate-water system is deduced,and the cohesive energy of asphalt and the binding energy between asphalt and aggregate are calculated.Based on this,this paper proposes the matching evaluation indicator to evaluate the combination of aggregate asphalt.According to the evaluation index of surface energy matching,a reasonable test is designed to verify it.By selecting a variety of typical aggregate and asphalt,the matching index of asphalt aggregate combination is calculated.According to the domestic standard,the paper designs the reasonable adhesion and water stability test,and analyzes the relationship between the surface energy theory matching index and the macroscopic adhesion performance and water stability index.The results indicates that the surface energy theory results are in good correlation with the macro test results,and the evaluation index of the surface energy theory can accurately quantify the adhesion performance,which has broad application prospects.Through the research on the road raw materials of several expressways and nearby quarrying plants,the samples were collected to test the surface energy parameters,and the typical aggregate asphalt surface energy matching database was established.The calculation process of the surface energy evaluation index is programmed to calculate the cohesive energy of various materials and the binding energy and matching index of the selected asphalt and aggregate.It is convenient to choose out the asphalt aggregate with better matching as the road material,which can provide guidance for engineering practice and provide scientific basis for the selection of raw materials in asphalt pavement construction. |
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