Enhancing Weak Soil Strength in an Eco-friendly and Sustainable Manner: Reusing Waste from Indigenous Bamboo Dwellings in Arunachal Pradesh

This study focuses on exploring the sustainable and environment-friendly use of waste generated from local bamboo houses, bamboo, and wood waste to improve the geotechnical properties of weak soil. Soil samples were collected from Hoj-Potin Circle, Papumpare district of Arunachal Pradesh, India. Wood ash and bamboo fibre were added to the soil samples at varying proportions (5%, 10%, and 15% for wood ash and 1%, 1.5%, and 2% for bamboo fibre). Various experiments were conducted to find soil type, index properties, and strength parameters. Unconfined Compression Strength (UCS) tests were performed at curing intervals of 0, 7, 14, and 28 days, along with soaked and unsoaked California Bearing Ratio (CBR) tests, to assess the impact of bamboo fibre and wood ash. Additionally, higher percentages of wood ash and longer curing times enhance the UCS values of soil–wood ash mixtures, while the UCS values increase with the addition of bamboo fibre, peaking at 2% bamboo content. The highest UCS values were observed in soil–bamboo fibre-wood ash mixtures. The highest unconfined compression strength value for this mixture, 733 kPa, was found, making it the optimum mix overall. Furthermore, the addition of wood ash improves CBR values for both unsoaked and soaked conditions, and increasing bamboo fibre content by up to 2% leads to higher CBR values. The combination of soil mixed with bamboo fibre, and wood ash (S + 2%BF + 15%W mix) produced the highest CBR values out of all the mixtures. The unsoaked and soaked CBR values for this mix were recorded as 21.76% and 18.5%, respectively. Notably, the combination of 5% wood ash and 1.5% bamboo fibre met the criteria for suitable subgrade soil according to IRC SP: 2007, with a soaking CBR value of 12.13%. This environment-friendly and sustainable alternative to cement proves cost-effective and beneficial, promoting eco-conscious practices in soil stabilization techniques.