Sustainable Application of Wool-Banana Bio-Composite Waste Material in Geotechnical Engineering for Enhancement of Elastoplastic Strain and Resilience of Subgrade Expansive Clays

Abstract

Agro-biogenic stabilization of expansive subgrade soils is trending to achieve cost-effective and sustainable geotechnical design to resist distress and settlement during the application of heavy traffic loads. This research presents optimized remediation of expansive clay by addition of proportionate quantities of waste renewable wool-banana (WB) fiber composites for the enhancement of elastoplastic strain (ԐEP), peak strength (Sp), resilient modulus (MR) and California bearing ratio (CBR) of expansive clays. Remolded samples of stabilized and nontreated clay prepared at maximum dry density (γdmax) and optimum moisture content (OMC) were subjected to a series of swell potential, unconfined compressive strength (UCS), resilient modulus (MR) and CBR tests to evaluate swell potential, ԐEP, MR, and CBR parameters. The outcome of this study clearly demonstrates that the optimal WB fiber dosage (i.e., 0.6% wool and 1.2% banana fibers of dry weight of clay) lowers the free swell up to 58% and presents an enhancement of 3.5, 2.7, 3.0 and 4.5-times of ԐEPT, Sp, MR and CBR, respectively. Enhancement in ԐEP is vital for the mitigation of excessive cracking in expansive clays for sustainable subgrades. The ratio of strain relating to the peak strength (ԐPS) to the strain relating to the residual strength (ԐRS), i.e., ԐPS/ԐRS = 2.99 which is highest among all fiber-clay blend depicting the highly ductile clay-fiber mixture. Cost-strength analysis reveals the optimized enhancement of ԐEPT, Sp, MR and CBR in comparison with cost using clay plus 0.6% wool plus 1.2% banana fibers blend which depicts the potential application of this research to economize the stabilization of subgrade clay to achieve green and biogeotechnical engineering goals.

Prediction of Compression Index from Secant Elastic Modulus and Peak Strength of High Plastic Clay Ameliorated by Agro-Synthetic Waste Fibers for Green Subgrade

“…Now-a-days, waste fibers are replacing lime for stabilization of clays as an environmentally-friendly green alternative material to attain sustainable and ecoenvironmental construction goals [10,11]. The addition of fibers causes the enhancement of the elastic properties of clays, which are requirements for effective subgrade design for heavy-loaded pavement [12]. Eco-friendly use of fibers is an effective method to improve the shear strength and bearing capacity, along with reducing the expansiveness and settlement of weak clayey strata [13].…”

“…It is worth mentioning that polyester fibers resist the piping in soil during erosion, and cracking in clay is reduced [20,21] Waste banana fibers are frequently available due to large cultivation volumes and are being used for enhancement of the mechanical properties of soil to attain high-strength, affordable fiber-clay design mixes [22]. Banana fibers, after conversion from hydrophilic to hydrophobic by chemical treatment, can be used effectively for the stabilization of high-plastic clays for use in subgrade construction [12].…”

“…Banana fibers, which are socio-economic waste material extracted from the banana pseudo-stem, can be used in soil stabilization [23,24]. High cellulose and low micro-fibril angle of banana fibers are significant for their use in soil strengthening [12]. Both polyester and banana fibers act in a combined pattern, due to which the clay shows adhesive forces between clay and fibers.…”

Eco-Friendly Processing of Wool and Sustainable Valorization of This Natural Bioresource

“…A combination of the expensive clay used as subgrade material in roads with wool and banana fibers provides a new, less costly composite which maintains a high level of the road's carrying capacity [231].…”

Micro to Nanolevel Stabilization of Expansive Clay Using Agro-Wastes

“…Sustainable embankment materials are desired globally by geotechnical experts from durability, cost-efectiveness, and optimization perspectives for civil engineering infrastructures [1][2][3][4][5][6][7][8][9][10]. Urbanization around the world is going on fast-track [11] due to which the problematic soils sites are also in demand for soils improvement (stabilization).…”