Research And Application Of High-Viscosity And High-Elastic Modified Asphalt Stress Absorbing Layer In Winter(Severe) Cold Area

Reflective cracking is one of common diseases in semi-rigid base asphalt pavement and semi-rigid base asphalt pavement reconstruction projects.how to suppress and delay the development of reflective cracking is the focus of domestic and foreign road workers.This study relies on the renovation of the asphalt pavements in the Zhangjiakou section of the Er(lianhaote)-Qin(huangdao)Expressway to study the prevention and treatment of reflective cracking.This paper mainly conducts related research from the following four aspects:The first aspect is the study of the the old asphalt pavement overlay structure based on the stress absorbing layer.Through the investigation of the technical status of the old paving road,it is found that the main disease is the reflective cracking.The pavements structure of the overlay layer is studied when the thickness is limited by the elevation,through the mechanical analysis of the old road section overlay structure by BISAR3.0 software,it is found that after overlaying the stress absorbing layer,the tensile stress at the bottom of the old road is reduced by 7.21% on average.The second aspect is the study on the technical properties of the stress absorbing layer constituent materials.The paving performance of two kinds of high-viscosity and high-elastic modified asphalt binder and a conventional modified asphalt binder were studied,and put forward the technical requirements of the stress absorbing layer asphalt binder in the winter(severe)cold region.Through the routine test of three asphalt binders and the PG classification of the US SHRP standard,it is found that the high-viscosity and high-elasticity A modified asphalt is most suitable for the asphalt binder of the stress absorbing layer in the winter(severe)cold region.The third aspect is to study the mix design of stress absorbing layer,mainly by using the American Superpave volume design method to study the mix design of stress absorbing layer asphalt mixture,and puts forward the mineral grading range of the absorbing layer in the winter(severe)cold region.The road performance of three stressabsorbing layer asphalt mixtures was studied by high temperature rutting test,low temperature bending test,freezing test,water immersion Marshall test,freeze-thaw split test and four-point bending fatigue test.The A modified asphalt mixture has good paving performance and it is most suitable asphalt mixture for stress absorbing layer technology in winter(severe)cold regions.The fourth aspect is to pave the test road for stress-absorbing layers of high-viscosity and high-elastic modified asphalt,and to study the construction process of high-viscosity and high-elastic modified asphalt stress absorbing layer.In summary,this paper conducts in-depth studies on high-viscosity and high-elastic modified asphalt stress absorbing layer in winter(severe)cold area through on-site investigation,mechanical analysis,indoor test and paving test road.The technical achievements and engineering experience that author gets in research can offer technical reference and engineering reference for renovation and maintenance of road engineering in similar areas and the design of new semi-rigid base asphalt pavement in domestic climate-like areas.