Study On Rigid Base Structure Of Recycled Aggregate

Semi-rigid pavement structure is the main type of pavement structure in China. Because of heavy traffic and many other reasons, the early damage of semi-rigid pavement structure is serious. Moreover, the early constructed freeway is going into the overhaul period one after another. The milled semi-rigid base material is enormous waste of resources, and result in a series of environmental problems. Considering the serious waste of milled semi-rigid base in freeway overhaul, a technique on reclaimed lime-fly ash macadam used in rigid base was studied.The concept of rigid base with mesh reinforcement was put forward. Load stress simplified model of rigid base with mesh reinforcement was set up, and the stress of asphalt pavement with recycled concrete base was analyzed. Under the standard traffic load and overload conditions, its stress and strain changing rules were obtained. Through the three-dimensional finite element method, stress-strain of rigid structures of different reinforcement under standard load and overload was calculated to determine the impact of different programs on the mesh reinforcement structures. The fatigue lives of asphalt pavement with different rigid base structures were predicted. The role of mesh reinforcement, the reinforcement net settings location and reinforcement ratio were determined.The temperature gradient of concrete base structure with asphalt surface was analyzed. The temperature field of pavement structure was obtained using three-dimensional finite element model. The thermal stress and coupling stress of asphalt pavement with concrete base were analyzed. Studies suggest that: the weatherof temperature dropped 15℃a day is rarely, unlike the vehicle load as thousandstimes every day. Taking the coupling stress as the calculation basis of fatigue life is unreasonable.Adopting thermal-stress coupling method, thermal stress of asphalt pavement with rigid base with different transverse joint spaces was calculated and analyzed. The transverse joint space suitable for rigid base of recycled aggregate was put forward. Studies suggest that temperature gradient and warping stress decreased sharply after paving asphalt concrete. The transverse joint space is controlled by extreme temperature reduction of rigid base in its curling period. The reasonable transverse joint space of recycled aggregate concrete base was recommended.In accordance with the specific requirements of composite structure of asphalt pavement with rigid base, the pavement structure was designed. Combined with engineering practice and theoretical basis, recommend the reasonable asphalt pavement structure with rigid base in the highway overhaul and give structural design procedures and design examples.Combined with theoretical analysis and experience both at home and abroad, trial pavement sections were constructed, the design and verification of recycled aggregate rigid base was carried out.