Moisture Sensitivity Of Warm Mix Recycled Asphalt Mixture Based On Theory Of Interface

Warm mix (recycled) asphalt is widely used as a new energy-saving, environmentally friendly road material. However, some studies show that the poor of splitting strength and moisture sensitivity of warm mix (recycled) asphalt is the technical bottleneck to promote the technology. Therefore, in this paper splitting strength and moisture sensitivity of warm mix (recycled) asphalt are study deeply based on theory of interface.Firstly, the basic properties of asphalt with or without Sasobit(?) are tested to analysis the affect of Sasobit(?), the change of functional groups is analysis by infrared spectroscopy. In addition, the evaluation of warm mix (recycled) asphalt mixture performance is impacted by RAP material variability, the RAP material variability and control measueres are analysied heavily combinated of recycled projects, to verifiy the results of control measures.Ensuring the stability of the raw materials, the AC13-C Sasobit(?) warm mix (recycled) asphalt is designed according to design method of ordinary hot mix asphalt, furtherly the effect of warm mix agent contents, RAP, mineral aggregate type, anti-stripping agent on splitting strength, freeze-thaw splitting strength and moisture sensitivity are studied.Secondly, surface and interface characteristics of asphalt mixture is theoretical analysied based on the basic principles of surface and interface materials, and the formula of asphalt-mineral aggregate adhesion work, asphalt cohesion is derivated. SFE, polar component and dispersion component of asphalt with different additives (Sasobit(?), anti-stripping agent) are measured through sessile drop method, and the effect of additives on SFE and each component of asphalt is analyzed. SFE and specific surface area (SSA) of limestone and granite are measured separately by capillary rise method and BET adsorption method. Mineral aggregate surface morphology are observed using scanning electron microscopy, for corroboration of specific surface area. work of adhesion between asphalts and aggregates, asphalt cohesion are calculated.Finally, relationships between SFE, each component, work of adhesion, RAP and splitting strength, freeze-thaw splitting strength of mixtures is analysied, in order to justify splitting strength, freeze-thaw splitting strength of mixtures; additionly, TSR and interfacial adhesion properties is exploratorily analyzed, in proposing appropriate measures based on interface adhesion relationship to improve moisture sensitivity preformance.The results show that:splitting strength and moisture sensitivity can be better explained by the theory of surface free energy. Sasobit(?) makes dispersion component of asphalt reduce, but polar component increase, so splitting strength, freeze-thaw splitting strength of mixtures with Sasobit(?) reduce legitimately. Because of new-aged asphalt adhesion work is much greater than the new asphalt-new mineral aggregate, blending RAP can improve the splitting strength. trying to analyze the relationship between TSR and surface free energy and related parameters, asphalt-mineral aggregate and asphalt work of adhesion cohesion C is as same as TSR, water stability performance of asphalt mixture is better with big C, asphalt-mineral aggregate adhesion adhesion work with or without water,the a and TSR trend similarily. water stability performance of asphalt mixture is better with big a. RAP blending significantly reduced water stability performance, the reasons may be that RAP reduces the difference of work of adhesion interface when water status and anhydrous state, but this conclusion needs further verification.