Study on recycling of waste asphalt blocks containing roadbed materials using new screenless separation equipment with a vibration device

Waste asphalt blocks from construction sites are usually processed in the recycling plants to be used as recycled asphalt aggregates. These blocks are usually fed into the grizzly to break them into small pieces and to remove the soil attached on their surfaces. At present, the soil content of grizzly-under-materials does not satisfy the required standard value (Japan Road Association, 1992). Therefore, it is necessary to reduce the amount of soils in the grizzly-under-materials, to be used as expensive recycled aggregates. In 2009, we developed an equipment to remove the soils from grizzly-under-materials. This equipment was able to reduce the amount of soils in the grizzly-under-materials, but the efficiency was not so high. In this study, this equipment was modified by adding a vibration device in order to reduce the pipe inclination angle and to keep the long processing time. It was found through the experiments that the vibration device worked well and efficiency to remove the amount of soils increased compared to the previous equipment. It was also found that, the highest equipment capacity to reduce the initial soil content in the grizzly-under-materials was equal to 1.66% and it was achieved with pipe inclination angle, amplitude, frequency and water content equal to 15°, 1 cm, 260 RPM and 5% respectively.