Research On Recycling Of Thermosetting Epoxy Asphalt Concrete

Epoxy asphalt concrete is a kind of pavement material with excellent performance,and is often used in key road infrastructure such as long-span bridges,long longitudinal slopes and tunnels with heavy traffic load and complex service environment.With the continuous deepening of the concept of recycling in the industry,epoxy asphalt is expected to be more widely used and popularized.In order to explore the economy and sustainability of epoxy asphalt concrete in the whole life cycle,this paper carried out a preliminary research on the recycling of epoxy asphalt concrete.First of all,in order to comprehensively evaluate the physical,mechanical and morphological characteristics of reclaimed epoxy asphalt pavement(REAP),through investigating the disease and structural composition of the original pavement,the particle composition and characteristics of REAP reclaimed material are preliminarily analyzed,and the results show that the particles of REAP reclaimed material still have high strength and structural integrity;using aggregate tests under different conditions,the differences of physical and mechanical properties between REAP reclaimed material and two kinds of natural aggregates are compared and analyzed,results show that the crushing resistance of REAP reclaimed material is similar to that of basalt,while the abrasion resistance is close to that of limestone;then,taking the limestone aggregate commomly used in general asphalt pavement as the control,the morphological characteristics of REAP reclaimed aggregate particles are studied by digital image analysis method.It is found that compared with limestone,the surface of REAP reclaimed material has richer angular structure.Secondly,starting from the particle level,the adhesion effect between the reclaimed material and new asphalt binder is qualitatively analyzed by water immersion test based on quality loss.The results show that the flaking rate on the surface of REAP reclaimed material is slightly higher than that of limestone.Starting from the material composition level,based on surface energy theory,the adhesion between reclaimed material and base asphalt,reclaimed material and asphalt mortar with different powder-to-rubber ratios are analyzed respectively.Two natural aggregates are used as control group,the adhesion work and peeling work between different aggregates and new asphalt binder are calculated to quantitatively analyze the adhesion characteristics of REAP reclaimed material.It is found that the adhesion work between REAP reclaimed material and asphalt binder is slightly higher than that of basalt,while the peeling work on the surface of REAP reclaimed material is at the same level as that of limestone.Starting from the macro-level of asphalt concrete,the adhesion effect between REAP reclaimed material and asphalt binder is verified by pull-out test.The results show that REAP reclaimed material has no obvious adverse effect on the internal bonding system of concrete.Finally,based on the physical and mechanical characteristics,morphological characteristics and adhesion characteristics of REAP reclaimed material,the compound regeneration method of REAP reclaimed material is designed.From the two aspects of regeneration method and the content of REAP reclaimed material,the road performance test verifies the advantages of compound regeneration method over conventional regeneration method.The results show that the maximum REAP content should be 50% when using compound regeneration method.Based on the adhesion characteristics of REAP,the road performance of recycled asphalt concrete with different powder-to-rubber ratios is optimized.It is found that the maximum allowable content of REAP reclaimed material can reach 75%when the powder-to-rubber ratio is controlled within 1.0～1.2.In this paper,the recycling of epoxy asphalt concrete is studied preliminarily,the differences of physical and mechanical properties and morphological characteristics between REAP reclaimed material and natural aggregate are explored;the adhesion characteristics between REAP reclaimed material and new asphalt binder are comprehensively analyzed from three aspects: particle,material composition and macro-level of asphalt concrete;the compound regeneration method and performance optimization measure suitable for REAP reclaimed material are proposed,which provides a reference for recycling and life-cycle cost research of epoxy asphalt concrete.