Laboratory Evaluation of Moisture Susceptibility and Rutting Potential of Warm Mix Asphalt

To protect environment and reduce the consumption of energy, warm asphalt technology has been used widely in recent years. There are different technology to produce warm mix asphalt. In this research Zycotherm nano material and Sasobit, which are respectively chemical and organic additives, as two sorts of warm mix asphalt construction trends were investigated. Although having many advantages, moisture susceptibility and rutting performance are two major concerns about warm mix asphalt that was investigated in this study. The functional characterization of the base bitumen with and without Zycotherm was analyzed by means of Fourier Transform Infrared Spectroscopy (FTIR). Overall, fifty four hot and warm mix asphalt mixtures were made. In order to check moisture susceptibility, Indirect Tensile Strength and resilience modulus tests, and to evaluate rutting potential of the mixtures, dynamic creep test were conducted. Results showed that Zychoterm nano material, in addition to the reduction it causes in mixing and compaction temperature, also improves moisture susceptibility of mixtures compared to control mix and the mixture with Sasobit. On the other hand, Mixtures with Zycotherm nano material had lower flow number than HMA and Sasobit mixtures, Generally reduction in temperature leads to less oxidative and subsequently to less rutting resistance, however, as it was expected because of the stiffer Sasobit modified binder, WMA mixtures containing Sasobit had significantly higher resistance to rutting than other mixtures.