Natural fibres have recently gained attention as an alternative sustainable material for civil engineering applications due to natural fibres’ exceptional performance, including high strength, and their environmental-friendliness and cost-effectiveness. However, there are disadvantages to using natural fibres in extreme environments. Therefore, this paper reviewed the effect of moisture content and temperature on the tensile strength of potential natural fibres for engineering purposes. Furthermore, this paper also critically reviewed the influence of alkaline treatment on natural fibres’ tensile strength. This is significant because alkaline treatment enhances surface friction and the fraction of the revealed cellulose on the fibres’ surface, resulting in better mechanical interlocking. In conclusion, natural fibres demonstrate their potential for geotechnical applications due to the materials’ strong tensile properties after being subjected to treatment processes.

Porous asphalt has excellent permeability and larger air voids. Due to the low stability strength of asphalt binder with aggregates, Malaysia uses porous asphalt roads for lightweight vehicle road transportation. Numerous studies indicate utilizing Recycled High-Density Polyethylene in porous asphalt road surface. As a result, it was utilised as an additional binder material to enhance the asphalt binder. The main purpose of this study is to investigate the stability of modified porous asphalt samples and evaluate the optimum percentage of HDPE plastic waste from 3%, 6% and 9%. The aggregates, asphalt properties, Marshall Parameters and waster absorption test are in comply with JKR Standard and PWD 2008. At 3% of plastic addition has improved the stability of porous asphalt specimens. Adding plastic waste as a binder helps strengthen asphalt binding.