Evaluating the change in the properties of bitumen during production, transport and construction of hot mix asphalt in the conditions of Vietnam

Abstract

In Vietnam, the total time of production, transport and construction of hot mix asphalt (HMA) can last up to more than 10 hours depending on the distance from the asphalt plan to the construction site as well as the weather conditions at that site. As a result, the properties of the onsite compacted asphalt mixture may be far different from those obtained in the laboratory, giving rise to unreliable predicted service life of the pavement. This study aims to evaluate the change in the properties of bitumen during production, transport and construction of hot mix asphalt. To simulate these processes, a 60/70 pen bitumen was heated to 150 °C for 1h, 3h and 5h and stirred continuously to allows the interaction between bitumen and oxygen. Control samples were also prepared by maintaining the bitumen at high temperature but not allowing the bitumen to interact with oxygen. The properties of the conditioned samples were then evaluated using viscosity test, penetration and softening point test, and Superpave performance grading (PG) test. The results show that the properties of the control samples almost do not change while those of the aged samples vary significantly with an increase of ageing time. The more longtime the bitumen was exposed to high temperature and interaction with air, the more stiffness gained by the bitumen.