Research On The Design Scheme Of Asphalt Pavement Heavy Repair Of Trunk Road In Northern Shaanxi Province

Maintenance is an important technical measure to maintain the quality of highway usage and ensure the smooth flow of highway traffic.At present,the heavy repair task of national and provincial trunk road is onerous,but the technical level of asphalt pavement heavy repair is backward,pavement structure is relatively simple,the utilization ratio of waste pavement materials is low,which cannot meet the current asphalt pavement heavy repair requirements.Therefore,it is very necessary and has important practical significance to take the trunk road in the northern Shaanxi area as the object and carry out the study on the design scheme of asphalt pavement heavy repair.First,typical road sections are chosen to carry out the investigation of the asphalt pavement usage,analyze the main disease types and characteristics of the asphalt pavement in the northern Shaanxi province and the disease characteristics of heavy repair asphalt pavement.The main diseases are cracks,rutting and water damage(manifested as loose and pit),in which the cracks disease is the most serious.The impact of heavy traffic on the performance and service life of asphalt pavement is analyzed based on the traffic survey.The asphalt pavement will not only produce fatigue damage,but also cause ultimate failure under effect of heavy traffic.According to the characteristics of asphalt pavement diseases and traffic composition of the trunk road in northern Shaanxi province,this paper puts forward the design principles of overhaul structure and the basic structure of overhaul pavement in the trunk road of northern Shaanxi area,including flexible base or composite asphalt pavement,semi-rigid asphalt pavement and recycled asphalt pavement,and pavement structures of heavy repair trunk road in northern Shaanxi Province are recommended,with the application notes attached.According to the stress state of cement cold recycled base layer,the strength control index of cement cold reclaimed mixture is studied.It is suggested that the cement cold regenerative mixture should be controlled by unconfined compressive strength and splitting strength,according to the tensile stress level of cement cold regeneration base and subbase bottom layer(unified value is 0.2884MPa),strength control standard of cement cold recycled mixture is set up,in which splitting strength standard is 0.20~0.25 MPa,the unconfined compressive strength standard is 1.5~2.0MPa.It is expected to enrich the overhaul structure of asphalt pavement of trunk highway,enhance the technical level of asphalt pavement heavy repair and improve the performance of overhauling asphalt pavement through the study of this paper,at the same time,the research results of this paper also have reference function for asphalt pavement construction.