Comprehensive evaluation of long-term aging of asphalt mixtures in hot climatic condition

Abstract

Aging is an inevitable phenomenon in hot mix asphalt production and during in-service period of flexible pavement operation. This paper presents an experimental evaluation of long-term aging of asphalt mixtures in Qatar. Aging of asphalt mixture was conducted on two different states i.e. (1) traditional compacted specimen at a temperature of 85°C and (2) loose mixtures at an elevated temperature of 135°C. Test results indicated that the current practice of asphalt mixture conditioning in a forced-draft oven to simulate long-term aging in the field is not sufficient for pavements in Qatar which experience the hot climatic condition. To simulate long-term aging of asphalt mixture in field, oven aging duration needs to be extended from the standard 5 days at a temperature of 85°C for compacted specimens to 75 and 45 days for wearing and base layer, respectively based on the dynamic modulus test results. Conditioning on loose mixtures at an elevated temperature of 135°C can be an alternative option in terms of time efficiency and cost.