Stabilization of Peat Soil with Silica Fume and Areca Fiber as Reinforcement: An Experimental Investigation

Abstract

The fast expansion of municipal areas and the rising demand for construction have led to a lack of land with optimal soil conditions. Consequently, builders often must utilize locally available weak soil, making soil stabilization an essential process. These techniques enhance soil strength and durability by altering its properties. While various soil stabilization techniques have been explored, limited studies focus on the combined outcome of silica fume and areca fiber in improving the strength and durability of peat soil in the context of Ziro Valley, Arunachal Pradesh. Various tests were done on soil specimens, including physical and index properties, compaction, UCS, CBR, SEM and EDX. Areca coir (2030 mm) improved soil properties up to 0.5% of its dosage with soil, but it encounters distribution issues at higher doses. Varied weight ratios of silica fume 6%,8% and 10% and 0.3%,0.5% and 0.7% areca fiber are used according to the soil type to achieve the best possible conditions. The strength of peat is significantly enhanced with the incorporation of silica fume due to its cementitious compound, leading to a rise in MDD and a decrease in OMC. The inclusion of areca reinforced in soil decreases MDD and increases OMC. In this study, the S+8%SF+0.5%AF mixture demonstrated the highest UCS value of 369.256 kPa after 28 days of curing, indicating its effectiveness in enhancing the strength of peat soil. Additionally, the S+10%SF+0.5%AF mixture showed the most significant improvement in CBR values, increasing from 3.45% to 13.71% (unsoaked) and from 2.27% to 11.1% (soaked). This represents a 388.98% increase compared to untreated peat soil. The S+10%SF+0.5%AF mixture thus meets the design requirements recommended for subgrade soil treatment. Microstructural analysis via EDX and SEM enhances understanding of soil strength and stability factors. Silica fume enhances soil stability, while areac fiber strengthens it, as shown through compaction, UCS, and CBR tests. Using these waste materials offers an economical and sustainable solution in engineering.