Abstract- The present study focuses on the design aspect of flexible pavement and quality control management, incorporating an experimental investigation on the use of natural fibers and waste materials in all layers of flexible pavement, including subgrade, sub-base, base course, and bituminous surface. Natural fibers such as coir fiber, jute fiber, and bamboo fiber were used due to their eco-friendly nature and ability to improve tensile strength and reduce cracking. Waste materials such as fly ash, plastic waste, crumb rubber, and C&D waste were used as partial replacements or additives in different pavement layers. The experimental program involved various laboratory tests such as California Bearing Ratio (CBR) test for subgrade soil, Proctor compaction test, aggregate impact and crushing tests, and Marshall Stability test for bituminous mixes. Different mixes were prepared by varying the percentage of fibers and waste materials to determine the optimum combination. The results showed that the addition of fly ash and coir fiber significantly improved the CBR value of subgrade soil, indicating better load-bearing capacity. Similarly, the use of C&D waste and natural fibers in sub-base and base layers improved aggregate strength and resistance to impact. In bituminous layers, the addition of plastic waste and rubber enhanced Marshall Stability and flexibility, resulting in improved resistance to rutting and cracking. Based on the improved material properties, flexible pavement design was carried out as per Indian Roads Congress guidelines, and it was observed that the thickness of pavement layers can be reduced without compromising strength and performance.
Labhade et al. (2026) studied this question.