Road Performance and Microscopic Mechanism Analysis of Modified Straw Fiber Asphalt Binder

Abstract

In this study, the correlation between the microstructure of straw fibers and the macroscopic properties of asphalt binders is investigated. Penetration, softening point, bending beam rheometer, and toughness tests are performed to investigate the relationship between the pavement properties of fiber asphalt binders and each of the fiber types and contents. Subsequently, a four-component test, SEM, Fourier transform infrared microscopy, and fluorescence microscope tests are performed to analyze the microstructure of the straw fiber and its effect on asphalt properties. The results show that the high-temperature performance and shear resistance of the asphalt binder were enhanced with an increase in the modified straw fiber content. The low-temperature performance and toughness of the asphalt binder were reduced because of excessive fiber, and the recommended fiber content is 1.5%–2.0%. The adsorption capacity of the modified straw fiber for the light components of asphalt increased by 5.4% on average, and the low-temperature creep capacity of asphalt decreased by 9.6%. The surface roughness of the straw fiber increased via modification, and the shear resistance, high-temperature deformation resistance, and stress relaxation ability of the asphalt increased by 23.1%, 6.5%, and 5.7%, respectively. The comprehensive properties of the asphalt binder with modified straw fiber are similar to those of lignin fiber.

Investigation on the Performance of Modified Corn Stalk Fiber AC-13 Asphalt Mixture

“…Lignin fiber was produced by Yancheng Denuo Engineering Co., Ltd. (Yancheng, China) Corn stalk fiber and modified corn stalk fiber were prepared in the laboratory through high-speed shear crushing, alkali solution soaking, drying, and other preparation processes [31], as shown in Figure 1. Table 2 displays the technical indications, while Figure 2 displays the appearances and microstructures of the three fibers.…”

“…With the passage of time and the deepening of research, many scholars have discovered that the performance of fiber in modified asphalt and asphalt mixture is related to the content and modification effect [28][29][30]. Wang et al [31] discovered that the corn stalk fiber modified by NAOH solution improved the adsorption of light components by asphalt, and the asphalt mortar exhibited superior resistance to shear, resistance to deformation at high temperatures, and ability to relax under stress compered to ordinary corn stalk fiber. Chen et al [32] discovered that the incorporation of modified corn stalk fiber improved the high-temperature deformation resistance and elastic recovery performance of asphalt, and its dispersion uniformity in asphalt mortar was better than that of lignin fiber.…”