Determination of in-field temperature variations in fresh HMA and corresponding compaction temperatures

摘要

Hot mix asphalt (HMA) compacted at low temperatures develops many distresses due to high air voids. Asphalt compaction operations in the field are mostly based on the experience of field staff. Hence, independent of the actual temperature of the HMA. In this study, temperature variation in hot mix asphalt (HMA) was investigated during paving operations at eight test locations in field. Two most commonly used HMA layer thicknesses i.e. 5 cm and 8 cm were studied. Temperature of the fresh HMA layer was noted at the centre, surface and at the interface points by four node K-type thermocouple assembly. The average laying temperature of the HMA for eight tests was calculated as 136.92 degrees C. Whereas, the average compaction start temperature for eight tests was noted as 127.81 degrees C which shows the critical temperature loss of 9.11 degrees C before the compaction starts. The average compaction end temperature calculated was 62.89 degrees C which is below the common cut off temperature of 80 degrees C. Temperature difference between day and night tests was 10 degrees C which can be attributed as the effect of sunlight. The results of this study can be helpful to the field staff in decision making during paving operations. (C) 2019 Elsevier Ltd. All rights reserved.