The Applied Research Of ATB Bituminous Stable Macadam Structure Used In Lin-He Highway Lower Layer

In recent years, with the rapid development of national highway, the performance of highway pavement also puts forward higher requirements. Accompanied by the demand of increasing traffic flow, canalized traffic and heavy traffic, the building materials, new process and new structure of highway pavement have come into being. Combined with the terrain, geology, climate and supply of raw materials in the project location, Lin-He highway in GanSu Province adopts pavement structure with4+6+7cm,of which the total thickness is17cm. The upper layer of pavement structure uses mastic asphalt rubble SMA-13, meanwhile the middle layer uses high-performance modified bituminous concrete superpave-20.Above all,the lower layer adopts dense-graded bituminous macadam ATB-25.The lower layer belongs to the flexible base which has good stability, strength, resistance to permanent deformation and good anti-fatigue properties.It has been applied in the selection of highway pavement structure and will be a very good prospects of development.This paper mainly focues on some problems about stable bituminous macadam pavement ATB-25including the requirements of raw material, the design of mixture ratio, construction technology and quality control. The following aspects of work are mainly done:1. According to the supply of materials, local traffic and climate, the characteristics of terrain, high demands on the pavement against water damage and crack ability and the study on the design project of pavement structure, we decide to adopt pavement structure with4+6+7cm, of which the total thickness is17cm. The upper layer of pavement structure uses mastic asphalt rubble SMA-13, meanwhile the middle layer uses high-performance modified bituminous concrete superpave-20.Above all,the lower layer adopts dense-graded bituminous macadam ATB-25.2. At the same time we study the problems about test mixing ratio on the raw materials of asphalt mixture, we define the aggregate gradation and optimum asphalt dosage by means of laboratory experiments and achieve the best quality via continuously adjusting to ensure the construction quality from the source.3. Starting from construction technology consisting of preparation of raw material mixing, transportation, paving, the RCC, seams, trimming and clear field, we make the serious analysis of the construction technology on the site which can assure construction quality of the ATB-25stable bituminous macadam pavement and put forward a series of measures of quality assurance.4. From the control of construction, raw materials, quality on the construction process, we carry on research in-depth on specific measures to protect the quality of ATB-25of the lower layer construction, and then make availably specific measures.The study of this paper has a certain referential significance of the similar construction projects in Gansu Province.