Influence of Temperature and Humidity on Mechanical Properties of Asphalt Mixtures at Medium and Low Temperatures

In order to clarify the influence of temperature and humidity on the medium and low temperature performances of asphalt mixture, the annual temperature and humidity of different regions in China were analyzed. Three typical humidity conditions were selected for experiment. Indirect tensile stiffness modulus test and low temperature splitting test were carried out on the treated samples, so as to evaluate the influence of temperature and humidity on the mechanical properties of the mixture. Results show that the annual absolute humidity in most regions of China is less than 25 g/m³, and the moisture uptake of asphalt mixture decreases with the increase of temperature. High temperature and humidity will induce the notable decline of Young's modulus and stiffness modulus of asphalt mixture at low and medium temperature, as well as the increase of ultimate strain and the decrease of tensile strength at low temperature. The humidity conditions at medium and low temperatures have no influence on the modulus, strength and strain. The fracture energy, dissipated creep strain energy and elastic energy decrease with the increase of absolute humidity. High temperature and high humidity lead to a significant decrease of fracture energy. Young's modulus of asphalt mixture is susceptible to the change of temperature and humidity conditions.