EVALUATION OF ASPHALT MIXTURE FOR ASPHALT DIRECTLY FASTENED TRACK

초록

Asphalt tracks haves been widely used in the Unites States, Europe, and Asia, but asphalt directly fastened track (ADFT) system has only been used in Germany. The ADFT system is sleeper laid on the surface of asphalt mixture layers. Asphalt concrete mixture has never been used in the area of railway infrastructure in Korea. The research has been initiated to develop the asphalt mixtures which are suitable for the surface of ADFT system and evaluate the performance of the asphalt mixture. To make impermeable asphalt mixture surface, the laboratory permeability test was conducted for asphalt mixtures of three different aggregate gradations using asphalt mixture permeability tester. Moisture susceptibility test was conducted using AASHTO T 283 test method. The stripping percentage of asphalt mixtures was measured using a digital camera and analyzed based on image analysis techniques. The analysis results showed only below aggregate gradations did not meet the required flow value and VMA of design criteria. The upper aggregate gradation showed the highest TSR value, the low stripping percentage of asphalt mixture and permeable coefficient. Based on the limited research results, the upper (finer) aggregate gradation is the most suitable for asphalt mixture for ADFT system which will be constructed in the first time of Korea railway history.