Experimental Study on the Performance of Asphalt Binder Modified by Waste Rock Wool Fiber

The feasibility of using waste rock wool fiber (WRWF) to modify asphalt binders was investigated via laboratory tests. Initially, the physical properties of WRWF were assessed through thermal stability tests and asphalt absorption tests. Then, Fourier transform infrared (FTIR) spectroscopy was employed to classify the asphalt modification by the fibers. Physical tests were subsequently performed to measure the penetration, softening point, and rotational viscosity of the modified asphalt binders. Finally, temperature scanning tests, master curve simulations, and multiple stress creep recovery tests were carried out by using a dynamic shear rheometer to analyze the high-temperature performance of the modified asphalt binder, and its low-temperature properties were evaluated via a low-temperature bending beam rheometer. The test results indicated that WRWFs did not exhibit a burnt black color, and the weight loss is within 1.6% in the thermal stability test. This demonstrates that these fibers can absorb asphalt with a physically modifying effect. Moreover, compared with virgin asphalt, modified asphalt binder has a greater softening point, greater rotational viscosity, and lower penetration. The addition of WRWF increased the deformation resistance ability of the asphalt at high temperatures and affected the crack resistance at low temperatures. Under the test conditions of this study, the recommended optimal dosage of WRWF for modifying virgin asphalt is 12%.