Abstract
Currently, portable equipment for recycling of waste asphalt concrete (ASCON) has been used. However, any air pollution control devices are not attached in the simple portable one. Thus, a lot of air pollutants have been produced from recycling processes of waste ASCON which resulted from aging of paved roads or repavement of roads. This study deals with a preliminary result of concentration analysis of air pollutants obtained from a pilot and a real recycling processes of waste ASCON using simple portable recycling equipment. Air pollutants were taken from 4 steps of the pilot recycling process including an initial heating by liquid petroleum gas (LPG), intermediate heating and melting (H&M) process, final H&M process, and pavement processes using recycled ASCON at the recycling site. Also, air pollutants were taken front 4 steps of the real recycling processes including an initial H&M, final H&M and mixing, loading of recycled ASCON to dump trucks, and at the recycling site after leaving the loaded dump trucks for real pavement sites. The air pollutants measured in this study include volatile organic compounds (VOCs), aldehydes, particulate matter (PM: PM1, PM2.5, PM7, PM10, TSP (total suspended particulate)). The identified concentrations of VOCs increased with increasing time or degree for H&M of waste ASCON. In particular, very high concentrations of the VOCs at the status of complete melting, which is exposed to the air, of the waste ASCON just before paving tv the recycled ASCON at the recycling site. Also, considerable amount of VOCs were identified from the recycling equipment after the dump trucks leaded by recycled ASCON leaved the recycling site for the pavement sites. The relative level of formaldehyde exceeded 80% of the aldehydes Identified in the recycling processes. This is because the waste ASCON is exposed to direct flame of LPG during H&M processes. The PM concentrations measured in the winter recycling processes, such as the loading and rotation processes of waste ASCON into/in the recycling equipment for H&M, were much higher than those in the summer ones. In particular, the concentrations of coarse particles such as PM7 and PM10 during the winter recycling were very high as compared those during the summer one.
