Climate impact on the durability of asphalt concrete

Abstract: Roads are subjected to traffic loads and varying climate conditions that eventually lead to different types of damage. Moisture in asphalt is one of the major causes of premature failure in asphalt pavements. In addition, moisture in the unbound layers and temperature in the asphalt concrete (AC) layers affect the structural response of pavements under loading, such as the tensile strain at the bottom of AC layers. This thesis focused on identifying the influence of climate on the deterioration of flexiblepavement and on the assessment of pavement performance with regard to variations of temperature and moisture content. Laboratory testing of AC with various mix compositions under repeated pore pressure loadings to quantify the influence of mixcomposition against moisture sensitivity was performed. The influence of climate parameters, i.e. moisture content and temperature on the tensile strain at the bottom of the AC layer, was also studied by means of a falling weight deflectometer andresponse measurements at full-scale pavement test sections. The results showed that binder content, air void content and pore pressure conditioning have a significant influence on the stiffness reduction of AC. In addition, the temperature and moisturecontent have yielded significant contributions towards explaining the strain at the bottom of AC layers. Relationships between climate impact and asphalt pavement properties have been proposed which may be useful in the evaluation and design offlexible pavement with respect to climate conditions.