Study On Preventive Countermeasures For Water-damage Of Asphalt Pavement In Southern Region Shaanxi Province

Semi-rigid base asphalt pavement in our country are mostly adopted,Water can be collected in the road,stranded in internal and surface structure at the top of the grassroots,under the action of vehicle load,water erosion on asphalt pavement under the action of a mesh cracks, cracks, pits, loose, pit slot, pumping pulp and other diseases. The emergence of these diseases mainly related to water, collectively known as the water damage. Water damage is mainly embodied in the early and early of road use, and shorten the service life of the pavement, increased the pavement maintenance cost. Highway departments began to water damage repair and prevention research and exploration, Large Stone Porous asphalt Mixes(LSPM) began try to use.This article through to the LSPM asphalt mixture development present situation and the analysis of the basic properties, combined with the southern Shaanxi warm temperate and subtropical climate and abundant rainfall, and mountains and highway longitudinal slope, many have triggered the characteristics of water damage, choose LSPM- 25 asphalt mixture water permeability structure layer water damage. According to the principle of Marshall test and Superpave rotating compaction method for asphalt mixture ratio design research. By the principle of Marshall test and Superpave rotating compaction method for asphalt mixture ratio design research. First of all, the asphalt and mineral aggregate performance test for raw materials, found shell type SBS I-C good viscosity of modified asphalt, stone hard, all the indexes can meet the requirements. Second, "bailey method" is adopted to improve the LSPM asphalt mixture of mineral aggregate gradation design, determine gradation composition for 10-30 mm: 10-15: mm: 5-10 mm: 0-5 mm: mineral powder= 59:16:13:10:2. In the case of rotating compaction times, 100 times, embedded skeleton structure basic formation, gradation composition is reasonable; Again, from the Marshall test, leakage test, the flying test and asphalt film thickness and so on comprehensive the optimum asphalt content of 3.3%. Finally, from the high temperature stability, permeability and water stability of mixture ratio, 4289 / mm measured dynamic stability, the permeability coefficient of 0.254, asphalt film thickness reach more than 12 microns. The indicators meet the requirements, determine the LSPM- 25 asphalt mixture is reasonable.According to determine the mixture ratio and the best dosage of asphalt mixing LSPM-25 in a highway pavement asphalt mixture, the worst in the summer season, flatness IRI value up to 1.93 mm, less than e. 2.4 mm specification, maximum rut depth of 4.4 mm, less than e. 5 mm specification. After a year of maintenance to traffic road as cracks, loose, chamfer of pits and pit damage phenomenon, use in good condition, explain LSPM big diameter drainage asphalt mixture has better anti-rutting ability and permanent deformation resistance, high temperature in southern Shaanxi province and the climate and traffic conditions suitable for highway asphalt pavement water damage prevention and control of similar areas.