LABORATORY PERFORMANCE OF ASPHALT CONCRETE CONTAINING COCONUT FIBRES

• Main Author: Roi Santoso, Sudiro
• Format: Theses
• Language: Indonesia
• Online Access: https://digilib.itb.ac.id/gdl/view/2979
• Institution: Institut Teknologi Bandung

</i><b>Abstract: </b><i><p align=\"justify\"> Fibres from the coconut shell is found in all areas of Indonesia and if it can be used effectively as an additive in bituminous mixture it may provide one solution to improve pavement performance.<p align=\"justify\"> This thesis describes a laboratory evaluation of asphalt concrete containing 0.01%, 0.03% and 0.05% coconut fibres by weight of total mix; nominal fibre lengths investigated were 0.5 cm, 1 cm and 3 cm. A total of 9 content/length combinations were thus investigated and for control purposes, mixes without coconut fibres were also investigated.<p align=\"justify\"> All mixes were designed by Marshall analysis and Marshall immersion, indirect tensile strength and wheel tracking tests were performed on mixes prepared at the optimum bitumen content.<p align=\"justify\"> Marshall analysis showed that coconut fibres content and length influenced optimum bitumen content. Asphalt concrete with 0.05% of 0.5 cm fibres had the lowest optimum bitumen content (6.0 %) while the mix with 0.05% of 3 cm fibres had the highest optimum bitumen content (7.1%). The optimum bitumen content of the mix with 0% fibre was 6.3%.<p align=\"justify\"> The mix with 0% fibre had the highest retained Marshall stability (89.08%). Of the mixes containing fibres, the mix with 0.01% of 0.5 cm fibres had the highest retained stability (87.49%). The mix with 0.05% of 0.5 cm fibres registered the best performance in the indirect tensile strength and wheel tracking tests. Its performance in these tests was superior to that of the mix with 0% fibre which in turn showed superior performance to that of the other fibres length/content combinations. The predicted value of mixture stiffness modulus at 25°C was also highest for the 0.05%/0.5 cm combination.<p align=\"justify\"> Difficulty was experienced in preparing mixes at the higher percentages of the longer fibres; intertwining of the fibres possibly caused localized weaknesses, contributing to the relatively poor performance of these mixes. Keeping the fibres length at 0.5 cm enabled the fibres to be distributed more uniformly throughout the mix thereby enhancing performance.</p>