Research On Evaluation Method Of Asphalt-Stone Adhesion Properties Based On Surface Free Energy

Diseases, such as loose, threshing, pockmarked face, pits, etc., because of asphalt-stone adhesion failure, can decline the usability of asphalt pavement endanger traffic safety. How to evaluate the asphalt-stone adhesive properties, provide reference and basis in the selection of asphalts and aggregates, maximize the usability and safety of asphalt pavement. It has a very important significance. To evaluation asphalt-stone adhesion at home and abroad fundamentally basis for the six adhesion theory(the theory of mechanical adhesion, chemical reaction theory, the theory of surface free energy, surface structure theory, molecular orientation theory, electrostatic theory), and deriving a lot of testing methods, for example water cooking method has the advantage of simple, fast, low cost, rapid assessment field adhesion levels, it is in fact the most typical of engineering evaluation method, the disadvantage is not quantitative indicators, it is difficult to accurately grasp the experimental conditions(such as " slight boiling " and the secondary pollution). The surface free energy based on the theory of sessile drop method as the contact angle method in the evaluation of asphalt-stone adhesion test method, because of its simple, quantitative evaluation, small human error and other features, has become a recent research hot spots to evaluate the asphalt-stone adhesive properties. At asphalt pavement performance, AASHTO T283 water stability evaluation method compared to freeze-thaw splitting and soaking splitting of conventional methods for asphalt mixture, the test conditions are more demanding, more closely combined with engineering practice.In this paper, sessile drop method as the test method, three kinds of typical asphalts and seven kinds of typical stones in Gansu Province as the research object. Water cooking method and sessile drop method assess asphalt-stone adhesion, meanwhile AASHTO T283 method assess water stability of asphalt mixture. By comparative analysis of three methods, in order to obtain an evaluation method of asphalt-stone adhesion it has better relate with road performance. Then quantitative and refinement the Gansu Province stone adhesion levels, to provide reference and basis in the selection of good compatibility with asphalts and aggregates.Firstly, the basis test analysis were carried out for the test object(asphalt and stone) such as the viscosity, infrared spectroscopy, SEM, base value, sand equivalent, etc., in order to distinguish the characteristics of different asphalt and stone.Secondly, the influence of asphalt-stone adhesion inner and outer factors are analyzed, test conditions are unified as 15.9mm stone polishing grades and 60 ? test temperature. Next to control external factors, under the same experimental conditions, the 21 kinds of combinations of three asphalt and seven stone were water cooking method, sessile drop method asphalt-stone adhesion test, AASHTO T283 asphalt mixture water stability test method to test, calculation asphalt-stone adhesion levels, adhesion work, freeze-thaw splitting strength ratio(TSR). The results show that under the same kind of asphalt, seven stone adhesion work on the order of Pingliang Shangyang limestone> Jade Bay serpentinite> Black Lake basalt> Dongle limestone> Yongdeng basalt> Chubolagou basalt > Dingxi granite. The same kind of stone under three asphalt adhesion work order was Kalamayi 90 #> SK90 # ? Zhonghaiyou 90#;.Finally, to compare the probabilistic relevance of adhesion level, adhesion works with TSR. The results showed that the coefficients of determination R2 adhesion level with TSR are 0.1956, 0.2731, 0.4793, the coefficients of determination R2 adhesive work with TSR are 0.8179, 0.7173, 0.7996, the sessile drop method and road performance have good correlation.