Preparation and Properties of an Active Cooling Antirutting Asphalt Mixture

Abstract

To reduce the temperature of asphalt pavements in summer and improve their high-temperature stability, tourmaline anion powder (TAP) was used as a modifier to prepare modified asphalt, which actively cools the pavement. The effects of different TAP contents on the high- and low-temperature performance of modified asphalt and its pavement cooling performance were studied based on the dynamic shear rheometer, low-temperature bending beam rheometer, and indoor rutting plate temperature difference tests; subsequently, the optimum TAP content was determined. Modified asphalt was used to prepare an active cooling antirutting asphalt mixture, and its pavement cooling performance was verified via outdoor lighting tests. High- and low-temperature dynamic modulus and low-temperature semicircular splitting tests were used to evaluate the high- and low-temperature performance; further, freeze-thaw splitting and immersion Marshall tests were performed to evaluate the water stability of the active cooling antirutting asphalt mixture. The results denote that TAP is useful for improving the rutting factor of asphalt. When the TAP content is 16% of the asphalt material, the maximum cooling value of the surface in laboratory tests becomes 5.9°C. When compared with an ordinary asphalt mixture, the dynamic stability of the active cooling antirutting asphalt mixture at medium and high temperatures increased by 18%–22%. The fracture energy can be increased by 12% at low temperatures. The maximum cooling value of the surfaces in outdoor tests is 7.2°C, and the water stability slightly decreases; however, it still satisfies the specification requirements.