Study On The Application Of High Viscosity Modifier In Porous Asphalt Mixture

With the continuous development of highway construction in China, people have paid more attention on the security and comfortability gradually than convenience in nowadays traffic environment. What is necessary for the highway construction department is to provide a safe, comfortable and environment-friendly traffic surroundings. With the feature of water draining and noise reduction, porous asphalt pavement meet the demand perfectly.The surface material of porous asphalt pavement is open-graded asphalt mixture, with a large void ratio which reaches up to 20%. Rain falling into the surface of the porous asphalt pavement, will be drained out of the pavement structure along the inner channel in the asphalt mixture. However, the open-graded porous asphalt mixture depends on modified asphalt binder with high viscosity to ensure its performance. In that case, the properties of high viscosity modified asphalt and its application in porous asphalt mixture are studied by means of experiments.In the paper, we first select 3 kinds of matrix asphalt and 2 kinds of high viscosity modifier. Comparing the properties of modified asphalts under the same content of modifier, we determined the matrix asphalt which has the best compatibility with the modifier. Using the selected matrix asphalt, we carry on the property study under the different content of high viscosity modifier, according to the results of performance test and economic factors, we make the final determination of the appropriate modifier and its mixing amount.After that, the paper carries on the mix proportion design for the porous asphalt mixture. Unlike the Marshall design methods for the common asphalt mixture, the design of porous asphalt mixture needs to ensure the aggregate gradation by controlling its void ratio first, then we get the range of optimum asphalt content by Cantabro Test and Schellenberg Binder Drainage Test. Taking Marshall test results into account, we ultimately determine the optimum asphalt content.Finally, we conduct the asphalt mixture performance test based on the selection of asphalt binding material and mix proportion design. It shows that, the performances of porous asphalt mixture meet the specification requirements, which indicates that the asphalt binder selection and mixture proportion design are reliable.