Research On Self-repair-deicing Asphalt Materials Based On Graphene/regenerant Microcapsules

Bitumen has the advantages of low cost,noise reduction and shock absorption.So bitumen is widely used as a bonding material in pavement engineering.However,Bitumen concrete is damaged by periodic vehicle loads.At the same time,the bitumen binder becomes brittle over time due to environmental impacts including aging and moisture damage.As a result,microcracks begin and expand to a larger scale,which accelerates the damage process and ultimately leads to proble M such as breakage,potholes,and cracking.And after the rain and snow in winter,the water or snow accumulated on the bitumen pavement is easy to freeze in the low temperature,resulting in a sharp decline in the anti-skid performance of the road.The survey shows that in the cold winter,15-30%of traffic accidents are caused by the road surface ice or snow.Improving the service life of bitumen pavement and improving the anti-icing and snow resistance of pavement have become the hotspots of today's research.Graphene microcapsules are one of the effective methods for solving the above two problems.In this paper,microcapsules with hybrid graphene/HMMM resin shell coated with bitumen oily rejuvenator were successfully prepared by in-situ polymerization method,and graphene/rejuvenator microcapsules were uniformly mixed with bitumen at high temperature to prepare bitumen/graphene microcapsules composites.And the preparation process of graphene microcapsules,the physical and chemical properties of graphene microcapsules,and the influence of the addition of graphene microcapsules on the rheological properties of bitumen materials,the electrical and thermal conductivity of asphalt/graphene microcapsules composites,anti-icing performance,self-healing performance was systematically studied.It was found through research that the microcapsule sample graphenes prepared at p H=5 was deposited on the shell in the largest amount.The microcapsule samples prepared under the condition of p H=5 has the best thermal stability and a large thermal conductivity.The thermal decomposition temperature is 330 ^oC and the conductivity value is 6.6805 W·?m·K?^-1.Because there is more graphene in the shell of the samples.In addition,the single microcapsules of this sample have the maximum yield stress?1.85 MPa?for the nanoindentation test.Fluorescence microscopy and XCT studies confirmed that the graphene microcapsules were uniformly dispersed in the bitumen without exhibiting agglomerated state.The BET test value of the graphene microcapsule samples indicate that the microcapsules have a small particle diameter and a large specific surface area.The smaller the particle size of the microcapsule,the higher the softening point of the composite material,and the larger the particle size of the microcapsule,the better the ductility of the composite material.The FT-IR curves indicate that the microcapsules have a chemical linkage to the bitumen macromolecule.These chemical linkages can form a network or bridge,resulting in a tight binding of the bitumen macromolecules to the microcapsule particles.The G*values indicate that the addition of smaller microcapsules enhances the elastic behavior of the composites.Adding more microcapsules also causes the G*value to become larger,which means that the elasticity of the bitumen increases.These values are consistent with physical properties,and the phase angle values also demonstrate the above results.The ice resistance of the composite was evaluated by analyzing the shear force values of the ice.It has been found that the ice shear strength values of the bitumen/graphene microcapsule samples are much smaller than the values of the bitumen/microcapsule without graphene samples.This result is mainly attributed to the higher thermal conductivity and higher electrical conductivity of bitumen samples with graphene microcapsules.It has also been found that these two values are increasing as the amount of graphene microcapsules added increases.The self-healing efficiency of the bitumen/graphene microcapsule composite samples were successfully evaluated by the beam on elastic foundation?BOEF?.The above analysis provides data support for bitumen/graphene microcapsule composites to solve road anti-icing and road self-healing problems.