Masumi OKUBO

Study on Basic Physical Properties of Modified Asphalt and Its Mixture with Resin with Improved Temperature Characteristics

Osamu TAKAHASHI

The design period of asphalt pavement in Japan is generally 10 years. But, in order to reduce the life cycle cost by extending the service life of the pavement, a new structural design with a design period of 20 years for asphalt pavement has been established. To extend the life of asphalt pavement, highly durable asphalt mixture is used. To make this mixture, the polymer-modified asphalt (PM-As) is an essential material.
However, the use of PM-As with an increased amount of polymer makes it difficult to control production and temperature, also the workability deteriorates due to the viscosity increase.
In order to solve these problems, modified asphalt using special resin in addition with a polymer as modifier was developed. This modified asphalt is made by adding a resin with improved temperature characteristics to the PM-As type ‡U without increasing the amount of polymer added. To use this modified asphalt as a product, it is necessary an evaluation to the basic performance of the asphalt and data about the amount of special resin with high modification effect.
In this study, diverse tests were conducted on the modified asphalt containing special resin at binder level, asphalt concrete level, and asphalt mixture level without compaction. Additionally, the performance as an asphalt binder was also evaluated. The purpose of this study is to quantitatively evaluate the improvement effect of the binder performance by the addition of special resin.
Through the binder level test, it was found that the addition of special resin increased the load during binder elongation and had about the same deformation resistance as PM-As type ‡V with a large amount of polymer added. It was also found that the modification effect was highest when the amount of special resin added was 10%. In the evaluation of asphalt concrete level, it was confirmed that the addition of special resin was effective in improving the plastic deformation resistance of asphalt concrete, but slightly reduced the crack resistance. Finally, It was found that the use of modified asphalt to which special resin was added was easier to work with asphalt mixture than PM-As type ‡V.