Bituminous Pavement Pit Slot Type Fast Durable Cold Patching Materials Research

At this stage,China's highway network construction has been basically completed,highway maintenance has become an urgent problem to be solved.The pot hole is one of the most serious deterioration forms of asphalt pavement in China.It not only affects the asphalt pavement performance and driving comfort,but also shorten the service life of the road.According to the statistics,the effects of repair materials are uneven.Therefore,it is necessary to develop new repair material with high strength,good durability and early strength cold patch material.In this paper,emulsified asphalt was firstly modified by SBR to improve the high and low temperature performance and adhesion of emulsified asphalt.The influence of the content of SBR latex on the performance of modified emulsified asphalt was studied.The viscosity,adhesion,storage stability and microscopic properties of SBR modified emulsified asphalt and the three indexes of its evaporation residue under different latex contents considered in determining the optimum amount of latex in emulsified asphalt.The SBR modified emulsified asphalt was then modified by waterborne epoxy resin.The optimum ratio of water-based epoxy resin and curing agent and the best amount of mixed solution in SBR modified emulsified asphalt were determined by experiment.It is found that the addition of epoxy in the SBR modified emulsified asphalt has improved the basic properties as three indexes of the emulsified asphalt again.Through the correction of the design method of the cationic emulsified asphalt mixture of the technical specifications for construction of Highway Asphalt Pavement,the design method of the cold mix method was used to determine the optimum emulsion dosage of SBR modified emulsified asphalt mixture and SBR epoxy modified emulsified asphalt mixture using Marshall stability.The capacities of the two coldmixes to resist permanent deformation(described as dynamic stability)at high temperature,anti-cracking property at low temperature,and the sensitivity to moisture damage were examined and compared.The resistance of the cold mixes(expressed as freeze-thaw splitting strength)is improved,helping to improve the anti-fatigue properties and durability of the cold mixes.Finally,with regard to the characteristics of emulsified asphalt cold admixture with high porosity,low saturation,low stability and slow formation after paving rolling,the cement and lime were used to further improve the modified cold mixes.The optimum mixing conditions of cement and lime were determined by experiments.Basic properties of the SBR epoxy modified emulsified asphalt mixture were compared.The porosity was decreased.The stability and dynamic stability of the cold fill material are improved.The stability,mechanical properties and high temperature stability of the cold mixes are improved,so does the stability,anti-fatigue properties and durability of the mixture.The fatigue properties of the lime-SBR-modified emulsified asphalt mixture were found to be better.The preliminary analysis was due to the ultimate bearing capacity and flexural strength of the mixture.The research results can provide the direction and thinking for the research of the highway asphalt pavement cold patching material,and provide the reference for the cold repair asphalt mixture performance indexes.At the same time,the cold patching material has good bonding performance and high forming strength,which can improve the repair quality of pavement pot hole.