Influence of natural fibers (kenaf and goat wool) on mixed mode Ⅰ/Ⅱ fracture strength of asphalt mixtures

摘要

Asphalt mixtures are one of the most prevalently used materials in road structures. The aim of this paper is to investigate the influence of natural fibers (i.e., kenaf and goat wool) on fracture strength of asphalt mixtures. Both fibers with three different lengths (i.e., 4, 8 and 12 mm) and contents (i.e., 0.1, 0.2 and 0.3% by weight of total asphalt mixture) are used to prepare asphalt mixtures. Fracture experiments are conducted under various mode mixities (i.e., pure mode I, pure mode II and two mixed modes of III) using SCB (semi-circular bend) specimen at a low temperature of -15 degrees C. The results reveal that both the kenaf and goat wool fibers improve the fracture strength of asphalt mixtures significantly. Findings of this research indicate that the kenaf and goat wool fibers are promising materials for manufacturing asphalt pavements. However, the asphalt mixtures reinforced by 0.3% kenaf fibers with 8 mm length and 0.3% goat wool fibers with 4 mm length demonstrate the best results compared to other mixtures studied in this research. Furthermore, the kanaf and goat wool fibers are found to be suitable for the dominant mode I and dominant mode II loadings, respectively. (C) 2019 Elsevier Ltd. All rights reserved.