The Effects of ZycoTherm Nano Materials on the Tensile Strength of Asphalt Mixtures in Cold Regions (A Case Study: Saghez)

As the asphalt temperature decreases, the tensile stress increases. If the tensile stress in the asphalt is greater than its tensile strength, the pavement asphalt cracks. Previous studies have focused on improving asphalt performance at high temperatures, while asphalt performance is neglected at low temperatures. Therefore, the purpose of this study is to investigate the effect of ZycoTherm nano-materials as an additive and asphalt modifier at low temperatures. For this purpose, four types of asphalt mixtures were prepared from the silica materials of the plant where the asphalt was produced. The first type was used a control sample with no additives, the second type was prepared with 0.1% nanocomposite additive, the third type with 0.15% of the additive and the fourth type with 0.1% additive and cement filler. Each type of mixture was tested with three specimens in a dry state and three samples in a saturated state, a total of 24 test specimens. Indirect tensile strength and tensile strength ratio values of specimens were measured in dry state after the freezing and melting cycle on the samples. The results showed that 15 % of ZycoTherm could increase the tensile strength in the dry state, but the effect of 0.1 % of ZycoTherm was higher than the 15 % of ZycoTherm. According to the results of the indirect tensile strength test, the highest strength belonged to the additive of 0.1% ZycoTherm nanocomposite with cement fillers, which indicates that indirect tensile strength of samples has improved in dry state and after the freezing and melting cycle.