Application of the new viscoelastic method of thermal stress calculation to the analysis of low-temperature cracking of ashpalt layers

High Modulus Asphalt Concrete base course of a motorway under construction cracked severely during the first winter after paving. The new viscoelastic method of thermal stress calculation was used to gain a better understanding of the mechanism of thermal stresses and development of low-temperature cracking in asphalt layers. This paper presents pavement structure and materials, thermal cracks intensity assessment, field and laboratory testing and the outline of the new viscoelastic method. Thermal stresses in the HMAC base course were calculated at its surface and at the depth of 5 cm at the time when transverse cracking occurred. The calculated thermal stresses were compared with tensile strength of the material. Probability of low-temperature cracking was determined. The results presented in the paper confirmed that the new method of thermal stress calculation was a valuable tool for analysis of low-temperature cracking. Several uncertainties and unsolved issues related to low-temperature cracking, which were discovered during the analysis, were described.