Research On Composition Design And Performance Of Open-graded Large Stone Asphalt Mixes

The reflection of asphalt pavement cracks and durability is one of the issues to be resolved. Open-graded Large Stone Asphalt Mixes (OLSM) with greater flexibility and greater deformation, can significantly delay the reflection crack of asphalt pavement;On the other hand, from greater porosity the water can flow out asphalt pavement, which can solve premature water damage,thus promoting the durability of the pavement. On the basis of domestic and international research, this paper studies the composition design and pavement performance of OLSM.By Means of Using the varying i method to design aggregate gradation and experimental study, the paper etermines gradation range of OLSM-25.According to its characteristic, scattering loss test and drain-down test are used to determine asphalt content range,in which the Marshall test is adopted to determine optimum asphalt content. During the test, stability, flow value, porosity and other control indicators of OLSM are recommended.The high-temperature stability, water stability, crack resistance and mechanical properties of OLSM are studied. The results of rutting test show that OLSM has good high temperature stability,and dynamic stability decreases gradually,as the coarse aggregate is enhanced. Immersion Marshall test results show that the water stability of OLSM is avorable. Compared with other asphalt mixtures, cracking test results show that crack resistance of OLSM is better. Finally,according to laboratory tests,construction technology and quality control of OLSM pavement are summarized by paving the testing pavement.