COMBINATION OF COIR FIBER WASTE AND COIR-WOOD ASH FOR EXPANSIVE CLAY STABILIZATION

Abstract

Coir waste randomly mixed into soil is an alternative material for strengthening expansive clay. However, these materials cannot reduce swelling due to water, requiring chemical stabilization. This study combined coir fibers with a mixture of coir-wood ash, the waste from the tofu home industry. No studies have utilized such a combination of structural materials. This study aims to examine the soaked and unsoaked California Bearing Ratio (CBR), swelling, unconfined compressive strength (UCS), and tensile strength of soil mixed with 0.75% fibers, and ash with varying content: 0%, 2%, 4%, 6%, 8%, and 10% of the mixture’s total weight. The curing time was seven days, 14 days, and 28 days. Testing refers to ASTM. The test results unveiled that the unsoaked CBR, soaked CBR, UCS, and tensile strength increased with rising ash content and curing time. A 6%–8% ash content produced the highest CBR, UCS, and tensile strength. On the other hand, by including a 6%–10% ash content, the swelling was decreased to 0%. Combining coir fiber and coir-wood ash has proven very effective for stabilizing expansive clays. In comparison to soils merely reinforced with fiber, the addition of coir-wood ash can eliminate swelling and increase the value of soaked CBR, UCS, tensile strength, and secant modulus up to 534%, 349%, 105%, and 824 %, respectively.