Low temperature cracking problem for asphalt pavements in Kazakhstan

Abstract

Low temperature cracking is one of the major causes of failure of asphalt pavements in Kazakhstan where minimum pavement design temperature is between -28 and -46 °C. Thermal stresses in the asphalt pavement were calculated as a function of its relaxation modulus and temperature changes. The parameters of modified CAM model for relaxation modulus of bitumen were related with its penetration index and softening point by formulas based on Van Der Poel’s nomograph. Hot mix asphalt relaxation modulus has been described by Christensen- Bonaquist model. Hot mix asphalt tensile strength as a function was related to the bitumen stiffness by equation based on Heukelom’s data and Molenaar-Li formula. The strength of mix has been also studied by performing tensile tests. The results were analyzed considering the calculated stress increase with temperature drop, and critical temperature was estimated.