Laboratory Investigation on the Use of Bamboo Fiber in Asphalt Mixtures for Enhanced Performance

This study evaluated the use of bamboo fiber, which is a new member in the natural fiber category, in dense-grade (DG) and stone matrix asphalt (SMA) mixtures for enhanced performance. Bamboo fiber has high tensile strength in fiber direction, and it also has rough surface texture comparable to that of a commonly used lignin fiber. Moreover, bamboo fiber exhibits sufficient thermal stability, which is a typical concern of plant-based materials. Marshall mix design procedure was followed to select optimum asphalt binder contents of DG and SMA mixtures that contain various amounts of bamboo fiber. Effects of bamboo fiber on mixture moisture susceptibility, rutting and low-temperature cracking performance were evaluated using the immersion Marshall, freeze-thaw cycling tests, wheel tracking test and three-point bending beam test, respectively. Testing results showed the use of bamboo fiber effectively enhanced the above-mentioned mixture performance. In addition, the optimum bamboo fiber contents for DG and SMA mixtures were found to be 0.2–0.3% and 0.4% (by weight of mixture). Finally, mixtures with bamboo fiber exhibited equivalent or better performance than the same mixtures with polyester fiber and lignin fiber, indicating the applicability of bamboo fiber in asphalt mixtures.