International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 6, Issue 2, pp: (65-73), Month: October 2018 - March 2019, Available at: www.researchpublish.com
Soft Soil Stabilization with Alkali Activated Sugarcane Bagasse Ash Jeevan Rana Magar1, Dr. Indra Prasad Acharya2 1,2
Department of Civil Engineering, Pulchowk Campus, Institute of Engineering, Tribhuvan University, Nepal
Abstract: Many civil engineering structures constructed on problematic soils like soft soil, swelling soil etc. faces a risk of failure due to insufficient bearing capacity and excessive settlement. Soft soils are typically replaced by some strong materials like crushed rock, hard soils etc. or treated with other cementing material for better engineering properties. High cost and negative environmental effects of traditional stabilizers like lime and cement etc. and the problem of disposal management of agriculture industrial wastes require the investigation of the potential use of agriculture industrial waste in the stabilization of these problematic soils that replaces the use of the traditional stabilizer in a project partially or completely. In this paper one dimensional compressive behavior (UCS) of the soft soil stabilized with sugarcane bagasse ash, by-products of sugar mill activated by alkali activator (NaOH & Na2SiO3) has been presented by performing laboratory tests at various proportion of bagasse ash content (15%, 25%, 35% of total solid mass), concentration of alkali (8M, 10M & 12M) and activator/alkali ratio (0.25, 0.45 & 0.65) at different curing periods (7, 14, 28 & 56 days). Test results showed a high reactivity of alkaliactivated binder promoting the strength development. UCS tests showed that maximum strength of 0.41 MPa is obtained for AB-25-12-0.25 mixture which is 1.78 times and 78.3% higher than raw soil at 7 days curing. Likewise 0.51 MPa for AB-25-12-0.25 mixture which is 1.89 times and 88.9%, 0.56 MPa for AB-25-12-0.45 mixture which is 1.93 times and 93.1% and 0.59 MPa for AB-25-10-0.65 mixture which is 1.97 times and 96.7% higher than raw soil at 14, 28 and 56 days curing respectively. The optimum bagasse ash content for soil stabilization is found to be 25% of total solids. Keywords: Soft soil, sugarcane bagasse ash, alkali activator, stabilization, UCS.
1. INTRODUCTION The soft soil typically characterized as a soil with low shear strength, high water content, highly compressible and low permeability. The techniques utilized for enhancement of the properties of these soils are known as ground improvement techniques which can be done either by some mechanical method through densification and reinforcement or by a chemical method by adding some admixtures in the soil. Engineering properties of soft soil are generally improved by cement stabilization method. CO2 emissions from traditional binder because of carbonate decomposition during its production contribute 7% of total artificial CO2 emission (Shahram Pourakbar, 2016). 1kg of carbon dioxide is released into the atmosphere from every 1 kg of cement manufacturing, which increases the greenhouse gas and possesses a serious threat to the global warming (Swain, 2015). The high cost of cement, negative environmental effects of cement stabilized soil resulted in the use of cheap, eco-friendly and sustainable materials for civil engineering application in low-cost infrastructures. Among various industrial or agricultural waste materials, sugarcane bagasse ash (SBA) which poses serious environmental problem may be the most efficient for soil stabilization. Bagasse ash is produced by burning the bagasse to cogenerate heat and electricity at high efficiency in sugar mills. Bagasse ash has been used extensively as a standalone stabilizer in soil stabilization and as additives in the lime or cement based stabilization to reduce the lime or cement content in concrete production as well as soil stabilization. (Chavan & Nagakumar, 2014), (Murari, 2015), (Sruthimol & Sindhu, 2015) and (Garg & Veena, 2016) investigated the soil properties using the various proportion of bagasse ash as a standalone stabilizer, they found that the plasticity index,
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