International Journal of Civil and Structural Engineering Research ISSN 2348-7607 (Online) Vol. 6, Issue 2, pp: (43-48), Month: October 2018 - March 2019, Available at: www.researchpublish.com
Problematic Clay Soils Modification Using Bush mango Fibre as Stabilizer Charles Kennedy1, Gbinu Samuel Kabari2, Letam Leelee Prince3 1
Faculty of Engineering, Department of Civil Engineering, Rivers State University, Nkpolu, Port Harcourt, Nigeria
2,3
School of Engineering, Department of Civil Engineering, Kenule Beeson Saro-Wiwa Polytechnic, Bori, Rivers State, Nigeria.
Authors E-mail: 1ken_charl@yahoo.co.uk, 2kabarisamuel@gmail.com,3leeprices076@yahoo.com
Abstract: Majority of the roads within the Niger Delta regions of Nigeria constructed on black cotton soils and are prone to severe cracks, degradation and differential settlement that has led to constant rehabilitation seasonally. The soils fell below standard for its application as road constructional materials. The study experimented on the use of irvinga gabonesis fibre(Bush Mango) to stabilized clay soils with percentage ratios of 0.25%, 0.50%, 0.75% and 1.0%. Preliminary investigations revealed the soils as A – 7 – 6 /CH on the AASHTO classification schemes / Unified Soil Classification System. The soils were dark grey in colors (from wet to dry states) with plastic index of 31.10%, 24.55%, 31.05%, and 32.17% respectively for Iwofe, Chokocho, Ndoni, and Ogbele Roads. The soils has unsoaked CBR values of 7.35%, 7.75%, 8.15%, and 7.85% and soaked CBR values of 6.35%, 6.23%, 7.05% and 5.55%. Unconfined compressive strength (UCS) values of 87.85kPa, 78.75kPa, 105.75kPa and 85.35kPa. Results of compaction test determination showed decreased in MDD values while OMC values increased, both parameters adhered to corresponding percentage increase ratios. Comparably, results indicated increased in CBR altered soils with optimum mixed percentage ratios of 0.7% to soils. Similarly, results of UCS stabilized soils increased with percentages ratio variations. Results showed low values of plastic index with corresponding percentage increased ratios. Entire results showed the potential use of irvinga gabonesis fibre for expansive soils treatment. Keywords: Clay soils, Irvinga Gabonesis Fibre, CBR, UCS, Consistency, Compaction.
1. INTRODUCTION Soil stabilization depends mainly on chemical reactions between stabilizer and soil minerals to achieve the desired effect. Generally, the additions of additives such as fibres to expansive soils increase the strength, bearing capacity and durability of the soil. Natural fibres such as hey, wood and bamboo have been used for the improvement of construction materials (Khedari et al. [1]), the use of appropriate elements in soil improves its engineering properties such as strength, hardness and deformability. Currently, natural fibres such as kenaf, coir, banana, jute, flax, sisal, palm, reed, bamboo and wood fibres are used for soil reinforcement and stabilisation (Ramakrishna and Sundararajan [2]). Charles et al. [3] investigated the effectiveness of natural fibre, costus afer bagasse (Bush sugarcane bagasse fibre (BSBF) as soil stabilizer / reinforcement in clay and lateritic soils with fibre inclusion of 0.25%, 0.50%, 0.75% and 1.0%. They concluded that both soils decreased in MDD and OMC with inclusion of fibre percentage, CRB values increased tremendously with optimum values percentage inclusion at 0.75%, beyond this value, crack was formed which resulted to potential failure state. Ghavami et al. [4] observed that the addition of 4 % coconut and sisal fibres to soil causes its deformability to increase significantly. Besides, the creation of cracks in dry seasons was highly lessened. Prabakar and Sridhar [5] studied on soil specimens reinforced with sisal fibres showed that both fibre content and aspect ratio have important influences in shear strength parameters (c, ∅). Bouhicha et al. [6] used the shear box test method to evaluate the strength of compacted earth reinforced with barley straw. Their work was part of a wider study of the physical and mechanical properties of fibre-reinforced compressed earth blocks. Their test results are showed that a 1.5 and 3.5 % (by weight of soil) addition of straw increased the apparent cohesion by up to 50 % (from 330 to 493kPa), but decreased the angle of internal friction.
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