International Research Journal of Engineering and Technology (IRJET)
e-ISSN: 2395-0056
Volume: 04 Issue: 07 | July -2017
p-ISSN: 2395-0072
www.irjet.net
Effect of Compactive Effort on Strength Characteristics of Black Cotton Soil Admixed with Eggshell Powder- Gum Arabic Mohammed Haruna1, Ali Musa Kundiri2, Suleiman Arafat Yero1 1 Department
of Civil Engineering, Abubakar Tafawa Balewa University, Bauchi State, Nigeria of Civil and Water Resource Engineering, University of Maiduguri, Borno State, Nigeria ---------------------------------------------------------------------***--------------------------------------------------------------------2 Department
Abstract— The effect of compaction energy of the British Standard Light (BSL), West African Standard (WAS) and British Standard Heavy (BSH) on black cotton specimens treated with 5, 10, 15, 20 and 25% eggshell powder (ESP) and 2, 4, 6, 8 and 10% gum-Arabic (GA) was studied. Atterberg’s limits, compaction California bearing ratio (CBR) and unconfined compressive strength (UCS) tests were performed on the specimens. The soil was classified as A-7-6 (13) by the American Association of States Highway and transportation Officials (1) and CH by the Unified Soil Classification System (2). The 7day unconfined compressive strength (UCS) Values of the natural soil using BSL, WAS and BSH compaction energies increase from 387, 451 and 324kN/m² respectively, while peak values of 644, 475 and 400kN/m² where recorded at 2%GA/5%ESP, 2%GA/15%ESP and 2%GA/5%ESP Treatments respectively were less than the UCS value of 1710kN/m2 requirement specified by road Note 31 (4). The soaked California bearing ratio (CBR) values of the ESP/GA stabilized soil increased from 9.4, 10.6 and 11.3% to a peak value of 10.1, 17.9 and 17.6% at 25%ESP/2%GA, 10%ESP/2%GA and 10%ESP/2%GA for BSL, WAS and BSH compaction energies respectively. An optimal blend of 10%ESP/2%GA is recommended for treatment of expansive black cotton soil for use as sub-grade material.
reduced thickness of bearing layer (7). The Expansive soils mostly found in the north-eastern part of Nigeria are dominantly referred to as “black cotton soils “it derives its name from some part of the world like India where cotton plant thrives well on them (5). Black cotton soils have colours ranging from light grey to dark grey and black.
Keywords—Eggshell powder, gum Arabic, California bearing ratio, Compaction, Unconfined compressive strength
1.1 Gum Arabic
1. INTRODUCTION Black Cotton soil mostly found in Africa and Asia are considered as Shrinks and swells soils. These types of soils are prone to failure of pavement, building and waste containment facilities in the north-eastern part of Nigeria and some regions of the world. (6). Black cotton soils shrink when they lose their moisture, but swell when they absorb water. It is typical to use modifiers or treatment agents such as additives to low-quality materials, which brings about improvement in the soil properties including decreased rate of subsidence, decreased adhesion coefficient in soils with high cohesion (clay), increased adhesion coefficient in soils with low cohesion (sand), reduced percentage of water absorption and prevention of soil expansion, reduced cost of earth structures (transport), speeded road construction operations, resistance to frost and defrost, improved ductility, reduced rigidity of earth structures, lack of weed growth in the surface of earth structures such as roads and © 2017, IRJET
|
Impact Factor value: 5.181
|
Two groups of parent rock materials that have been associated with the formation of expansive soils, comprises sedimentary rock of volcanic origin, which can be found in North America, South Africa and Israel, and the second group of parent materials basically entail the igneous rocks found in India, Nigeria and South Western U.S.A (5). The mineralogy of this soil is dominated by the presence of montmorillonite, which is characterized by large volume change from wet to dry seasons and vice versa. Deposits of black cotton soil in the field show a general pattern of cracks measuring up to 70mm Wide and over 1m depth during the dry season (5). One of the most common methods of improving fine soil is stabilization using additives that enhances the soil properties causing physical and chemical changes. It is, however, worth noting that fine soils behavior should be well studied before deciding on the method of soil improvement. (12).
Gum Arabic is a Biopolymer obtained from leguminous tree species that is well adapted to Sudan and sahellian agroecology of Africa, and it produces a natural gum made of hardened sap(17). Generally, there are two main types of gum Arabic used as hydrocolloids: Acacia Senegal and Acacia Seyal. The gum Arabic consists of a mixture of polysaccharides and glycoproteins which gives it the properties of glue binding that is edible by humans. The gums are sought after by the intentional buyers as Grade 1 (Acacia Senegal), Grade 2 (Acacia seyal), Grade 3 (Acacia Combretum) and Special Grade (Acacia Polycantha). (17). Nigeria currently produces 20,000 metric tons of gum Arabic annually that made it the second leading producer of gum Arabic in the world with Sudan as the leading producer, and Chad being next to Nigeria as the third largest producer of the product whose world production has been estimated at 70,000 metric tons annually. From available data, Africa produces about 98% of the world requirement of gum Arabic. Gum Arabic producing states in Nigeria includes Adamawa, Bauchi, Borno, Yobe, Jigawa, Gombe, Taraba, ISO 9001:2008 Certified Journal
|
Page 316