Warm mix asphalt (WMA) is a technology that reduces the temperature of asphalt mixing. WMA is expected to be one of the low-carbon technologies in Japan. This paper introduces the development history and current state of WMA in Japan, and explains the CO2 reduction effect of the WMA that we developed.WMA has been used in Japan since 1997. It was originally developed to reduce CO2 emission, but is now used for several different purposes such as to improve the quality of road construction during the cold season. Various companies develop WMA technology, and various types of WMA additives have been developed. Generally, WMA, which lowers the mixing temperature by 30 °C, is used for the purpose of CO2 emission reduction. WMA can now be supplied to most places in Japan. We developed a type of WMA that improves the CO2 reduction effect. One method that we developed is a way to make the mixing temperature 50 °C lower. We also developed a way to apply this method to a recycled mixture. As a result, we succeeded in developing a new WMA that has a greater CO2 emission reduction effect. Next, we estimated cold mix asphalt (CMA), which can be expected to have a greater CO2 reduction effect. This estimate showed that an excellent CO2 reduction effect could be obtained for the CMA. |