Application Research On Large Stone Filled With Cement Stabilized Macadam Base

With the leaping development of China’s transportation industry in the last decades,the demand for highway construction and maintenance is expanding rapidly.However,there are inevitable reflective cracks in early service of original semi-rigid asphalt pavement,which affects the quality of highway and puts strains on highway administration authority financially.Therefore,the thought of Large Stone Filled with Cement Stabilized Macadam(LSCM)is proposed in this paper.The application research on LSCM is of great significance for settling cracking problem in asphalt pavement.Firstly,based on gap-graded mixture theory,the diameter range of large stones(40-60mm)and nominal maximum aggregate size of filling cement stabilized macadam(9.5mm)are identified by Bailey method.Based on CAVF volume method,ratios of coarse and fine aggregate are preliminary determined by tapping density test.Construction gradation of base mixture is obtained through the above methods and allied construction techniques and quality control indexes are recommended.Secondly,the index of filling cement stabilized macadam for gradation control and the parameters of LSCM layer for pavement structure design are proposed on the basis of pavement performance test results.By calculations and analysis,it is recommended that material of LSCM works as reinforcing overlay on existing asphalt pavement or base layer on new asphalt pavement.The LSCM layer is under compression in the whole pavement.Then,LSCM is regarded as a kind of two-phase material composed by single particles of large stones and filling cement stabilized macadam.With a two-dimensional digital specimen generation program and an optimized cohesion embedding program,a meso-fracture FEM model is built by ABAQUS software.The model is validated by lab work.Finally,the study simulate partial compression test and temperature shrinkage test to analyze mechanism in resisting reflective cracking.The simulation results demonstrate that a better cracking-resisting performance is shown in LSCM than CM from the perspective of fracture morphology and strain energy.Parameters sensitivity analysis of cracking-resisting performance is conducted with regard to properties of coarse aggregates.Suggestions are put forward for gradation design and construction process depending on the results.