Effects Of Active Mineral Filler On Moisture Sensitivity Of Asphalt Mixtures

Moisture damage is the most common failure in asphalt pavement during its serviceable period. The deteriorations of asphalt pavement caused by moisture have been exhausted huge manpower and materials. Furthermore, the applications of secondary aggregates such as granite in asphalt mixture aggravate this problem. But the weak bond between the secondary aggregate and asphalt make them sensitive to moisture. The road based fly ash compound modifier (Active Mineral Filler) is able to improve the adhesion between aggregate and asphalt. The study was focused on the effects of active mineral filler on moisture resistance of asphalt mixture with granite or basalt, with the aim to enrich the application theories of AMF on asphalt pavement. It is important for the application of secondary aggregates in asphalt mixture.The viscoelastic properties of asphalt binder with AMF, hydrated lime and cement were investigated by thermal sweep during the temperature ranged from 30℃to 80℃. The results show that AMF improves the complex modulus of asphalt, as well as its serviceability at high temperature. The improvement of AMF on high temperature properties of binder is superior to cement, but inferior to hydrated lime.There are three moisture treated methods on asphalt mixture, which are the controlled, immersion in static water at 25℃and frost-thaw. The asphalt mixtures with AMF have better retained Marshall stability and indirect tensile strength ratio.Static creep test was executed to analyze the effects of AMF on the resistance of asphalt mixture to permanent deformation after moisture damage treatment. The results show that the additions of AMF significantly decrease the permanent deformation of asphalt mixtures, especially the mixture with basalt after moisture damage.In the indirect tensile resilient modulus test, the AMF increase the modulus of asphalt mixture with granite or basalt, of which the moisture saturations are 70%. The results further demonstrate that the AMF is able to improve the resistance of asphalt mixture to loss of stiffness caused by moisture damage. The asphalt mixtures with AMF are less sensitive to fatigue, compared to that with mineral filler in stress controlled mode. The AMF extends the fatigue lives of asphalt mixtures which have already suffered moisture damage.