Dynamic Mechanical And Interfacial Adhesive Properties Of Granular Asphalt Mixture

Granular asphalt mixtures are used widely in wearing courses,sealing layers and water-proof layers of bridges.How to accurately analyze the dynamic mechanical properties,interfacial adhesive properties and structural changes of granular asphalt mixtures with different aggregates and different environments has become a hot research topic at home and abroad.Both experiments and numerical simulation were used in this paper to study the effect of aggregate types,temperature,UV ageing and water damage on the dynamic and interfacial adhesive properties of granular asphalt mixtures,and the relativity between dynamic and interfacial adhesive properties was revealed.The findings of this paper are of important academic and practical significances for the research and application of granular asphalt mixtures.Firstly,Dynamic mechanical analyzer(DMA)and universal testing machine(UTM-25)were used to analyze the effect of the aggregate types,temperature,UV ageing and water damage on the dynamic modulus of granular asphalt mixtures.Statistical models were used to analyze the influence of these factors and the otherness of the indirect tension dynamic modulus and the three point bending dynamic modulus were analyzed.Results indicated that the influence of the factors on the dynamic modulus of granular asphalt mixtures decreased in order of environment,temperature,frequency and aggregate type.The indirect tension dynamic modulus and the three point bending dynamic modulus have good relativity with each other.Secondly,Fluorescence Microscope,three-dimensional depth of Field Microscope(3-D FM),Scanning Electron Microscope and Energy Dispersive Spectrometer analysis(EDS)were used to study the interfacial properties of asphalt mastic and granular asphalt mixtures.Asphalt adsorption test and surface tension test were used to verify the interfacial properties of granular asphalt mixtures.Results indicated that most failures of basalt granular asphalt mixture occurred within the asphalt mastic and few aggregates were exposed,so the cohesion failure dominated in basalt granular asphalt mixture.The cohesion failure also dominated in steel slag granular asphalt mixture,and the adhesion and cohesion failure acted together in andesite granular asphalt mixture.It indicated that the failure modes of granular asphalt mixtures had a significant correlation with aggregate types.Finally,Thin layer chromatography-flame ionization detection(TLC-FID)and X-ray diffraction(XRD)were used to characterize asphalt and aggregate compositions,and accordingly Materials Studio software was used to build the interfacial models of granular asphalt mixtures.Based on the models,the interfacial adhesive energy,the diffusion coefficients of asphalt,the failure modes of granular asphalt mixtures,the relativity between micro morphology and adhesive properties were explored.The following conclusions were obtained: steel slag granular asphalt mixture has higher interfacial energy than basalt and andesite granular asphalt mixtures;ultraviolet aging and moisture damage would promote the cohesive failure of asphalt mortar;Marshall Stability,fracture energy,interfacial morphology and interfacial energy of granular asphalt mixtures have good relativity with each other.