Study On The Key Technology Of Ultrathin Asphalt For Concrete Bridge Deck

Two-layer pavement is commonly used in Concretef bridge deck, with a total thickness of 80mm ~ 100mm. The Specification proposed that the thickness of layer is not less than 50mm for the application of single deck. Thin layer asphalt pavement of single deck with thickness less than 40mm, especially with thickness around 25mm, is still at an experimental stage. As a function layer, the main role of pavement layer is to provide a flat surface with good antiskid performance, at the same time to protect the main structure of the bridge and uniformly dispersed and transfer load. Therefore, minimize the thickness of asphalt pavement layers is reasonable, while the function of bridge deck pavement is satisfied. This paper is combining theoretical analysis and experimental study, and discussing some of the issues about the ultrathin layer of asphalt paving technology, the main research summarized as follows:â‘ It comprehensively studied the disease situation of asphalt concrete pavement on bridge deck and the main reason of ultra-thin layer of paving disease. Combined the findings, asphalt pavement damage can be divided into four categories: crack type, deformation and unconsolidated surface defects type. There are too many reasons caused Ultra-thin layers of asphalt pavement damage, but the mainly reasons don't neglect the less compacted asphalt mixture, the inadequate performance of waterproof binding and other external factors.â‘¡With a simplified model of BISAR3.0, it studied the mechanical characteristics of ultra-thin layer asphalt pavement, and the results indicate that the thick asphalt pavement is not better than the ultra-thin, because ultra-thin layer asphalt pavement is not easy to produce shear deformation lead to track, and the risk of the stress and strain increasing in rapid speed due to layer slip is lower than the double-deck. In addition, the condition of the contact between layers and overloading influence the shear stress of ultra-thin layer pavement obviously.â‘¢For the characteristics that thin asphalt is cooling too fast and not easy to compaction, it introduced the warm mixed asphalt, and mainly discussed the influence of the properties of asphalt binder, the compaction and road properties of asphalt mixtures which is partly under the condition of organic viscosity-type Warm surface active agents and temperature and mixed concentrate based on surface activity technology. The results indicate that the influence of the warm agents on asphalt binder is related to warm agent type, content and asphalt type. Warm agents can cut down the compaction temperature, while achieve higher compactness than hot mix asphalt mixture. High-temperature performance, low-temperature performance and water stable performance of warm mix asphalt mixture can reach or exceed the specifications, so it also apply to deck paving.â‘£It studied the test methods of interlayer bond strength at home and abroad, analyzed the differences and advantages of different methods, and utilized the parallel shear test between layers to partly discuss the influence of the interlaminar shear strength under the condition of the handling of cement concrete, temperature, humidity, type and amount of waterproof bonding layer, gradation type of asphalt mixture. The studies show that waterproof adhesive layer system is composed of cement concrete panels, waterproof bonding materials and asphalt concrete surface layer, so the latent problems in any one part would create damage for the pavement layer.