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.