Research On Asphalt-mix Functional Layer Between Surface And Base Layers Of Continuously Reinforced Concrete Pavement

CRCP is an important type of structure for high-grade pavement, which have long service life, need less maintenance and less energy consumption, simplify the construction, and have great adaptability to traffic grade and environlnent. In order to extend concrete pavement service life, an asphalt mixture functional layer is always put between surface and base layers, the dissertation studies on the thickness, material requirements and component design method. The study has important theoretical significance on reducing early damage, improving concrete pavement performance and building conservation-minded society.The dissertation analyzes common damage types of CRCP on the basis of CRCP interlayer action mechanism and transition layer theory, illustrates the necessity of setting functional layer between base and surface course of CRCP. The main functions of the functional layer are enhancing the anti-erosion ability and reducing reflective cracks in surface layer. The dissertation points out that the function layer is mainly wrecked by erosion and reflection, analyse the relationship between the modulus and thickness of functional layer and board top critical stress, and then decides the optimal thickness and least bitumen ratio for asphalt mix. By making the AC 16 and AC 13 mixtures by Mashall method and carring out water stability test and bending test on them, the dissertation decides the optimal thickness of asphalt mixture functional layer and the least bitumen ratio for resisting erosing and reflection cracking. According to the test results, the bitumen ratio for functional layer are 0.3% less than the optimal bitumen ratio determined by Marshell method, and this would not affact its ability of resisting reflection crcking.