Enhancing the Hydraulic Characteristics of Subgrade using Marble Dust and Coconut Shell Waste

Abstract

Subgrade materials are primarily defined by their capacity for sustained deformation under stress, which serves as an indicator of their strength or stiffness. The infiltration of rainwater into damaged pavement will have an impact on the performance of the subgrade. Submerging the subgrade in floodwater causes water to penetrate the subgrade pores, resulting in an increase in the subgrade's weight. This research aims to examine the effects of marble dust and coconut shell as additions to subgrade materials and further investigate the potential of utilising this hazardous waste to enhance the strength of the soil. This study investigates the hydraulic properties of the soil around the Universiti Pertahanan Nasional Malaysia (UPNM) campus, considering the addition of waste marble dust (MD) and crushed coconut shell (CS). The following ratio mixes of marble dust and coconut shell in this research are: MC1 (5:2.5), MC2 (10:2), MC3 (15:1.5), MC4 (20:1.0), MC5 (25:0.5), and a control sample without any additive. Laboratory experiments were conducted on the soil mixtures, which included sieve analysis, constant head pressure, and pressure plate extractor testing. The findings of the study indicate that the mixed-design MC1, consisting of 5% MD and 2.5% CS, demonstrates the most efficacy in improving the hydraulic properties of the subgrade. The primary focus of the Green Technology Master Plan Malaysia 2017–2030 is to enhance resilience to climate change and disasters by prioritising environmental sustainability. This is particularly highlighted in Chapter 6, which focuses on waste management.