Laboratory Evaluation of Rheological Properties of Asphalt Binder Modified by Nano-TiO2/CaCO3

Nanomaterials have a great potential for enhancing the performance of base asphalt binder. This study aims to promote the application of nano-TiO2/CaCO3 in bitumen and presents a study on rheological properties for TiO2/CaCO3 nanoparticle-bitumen. In this study, a series of laboratory experiments have been performed for bitumen with different nano-TiO2/CaCO3 dosages. Nano-TiO2/CaCO3-modified bitumen with optimum dosage was prepared for viscosity, dynamic shear rheometer (DSR), and beam bending rheometer (BBR) for assessing temperature sensitivity of bitumen, and the low-medium-high-temperature performances were analyzed for TiO2/CaCO3 nanoparticle-bitumen as well. Results show that bituminous mechanical properties were enhanced by TiO2/CaCO3, and based on the overall desirability analysis of various conventional tests, the reasonable dosage of nano-TiO2/CaCO3 was recommended as 5% by weight of base bitumen. Adding nano-TiO2/CaCO3 was beneficial to improve the viscosity and reduce the temperature sensitivity of bitumen. The capacities of bituminous rutting resistance as well as medium-temperature fatigue resistance were enhanced by the addition of nano-TiO2/CaCO3. However, BBR test shows that bituminous anticracking is reduced slightly. On this basis, the Burgers model is selected for clarifying the decrease in anticracking performance; that is, nano-TiO2/CaCO3 increased the stiffness modulus while increasing the viscosity of bitumen.