CHAPTER ONE 1.0 INTRODUCTION The search for alternative binder or pozzolanic material has become a challenge to national development. Potential of laterite soil as a reliable and durable construction material is highly locally available and has been one of the major building materials for a long time. One of the various soil types that occur in the tropic and sub-tropic laterite is one of the commonest types and is of special interest in building and road constructions. Laterite soils are highly weathered soil which contains large but extremely variable proportion of iron and aluminum oxides well as quartz and other minerals. AASHTO classified soils into seven groups. A – 1 to A – 7. According to the AASHTO subgrade classification system, residual soils are typically classified in the A – 2 category (AASHTO Designation: M 145 – 87). The glacial soil found in the northern states can be classified as either gravel (A – 1) sand (A – 2), Silts (A – 5) or silty clays (A – 6). The coaster soils along the eastern seaboard and in the gulf area are largely sands and gravel. Note, however, that within this region are extensive area of highly plastic clay (A – 7). According to Ola (1978) most lateritic soil for road fall within the A – 2, A – 6 and A – 7 group and lateritic soil have been found in the A – 3 and A – 5 group. Laterite is defined in Osula (1984) is a highly weathered tropical soil, rich in secondary oxide of any or a combination of iron, aluminum and manganese, manganese having been reported as a predominant element with combination with iron is some varieties of laterites notable those in India, Nigeria laterite soil are derived from basic igneous, metamorphic and sedimentary rock and can be found in the sedimentary basin and over the basement complex area of the country (Durotoye 1983). Laterite soil has been successfully used in various aspect of civil engineering construction project. Laterite materials are employed in the construction of airports, runways, highways, earth fill dam, low cost building etc. Osinubi and Kate (1997) have described laterite soil as the most common pavement materials in the tropics and sub-tropics. Some laterite soil, like laterite clays required improvement on the engineering properties before they can be used in any form of construction due to the fact that these soil have high swelling potentials which caused problem in construction thereby making them not favourable when used for construction materials in their natural states. 1.1 BACKGROUND OF THE STUDY A lot of research activities have been carried out on lateritic sills but little emphasis have been laid on the relationship between plasticity (consistency limit) and compressibility characteristics. Negligence on the part of construction engineers have led to uncountable road and structure failure within the Sub-Sahara Africa. According to Ashworth (1996), it was revealed that lateritic soils are graded with deficiency in sand and silt size particles. Ola (1974), investigated stabilization problems associated with laterite and the modified result is used in production of blocks. Balogun (1982), investigated some physical and geotechnical properties of laterite soil in Shagamu, Southwestern Nigeria, this found to have significant difference in some index properties and crushing strength of three Southwestern Nigeria lateritic clay deposits with the aim of seeing how the materials could be used for bricks. The result of the findings showed that firing increase the strength tremendously. A problem laterite soil is those that do not yield reproducible result using standard laboratory testing procedures. The soils are difficult to evaluate as engineering construction materials. The peculiar problem of this soil have been identified as thermal and mechanical instabilities i.e the susceptibility to significant change on the addition of small levels of the thermal or mechanical energy. This research project is to investigate the characteristic properties of lateritic soil located at Irewole Local Government, Ikire in Osun State, Opposite Saw Mill, by using Groundnut shell ash as an alternate binder at various percentage replacement to know the effect which those pozzolanic has on this selected laterite soil sample which will be determined in the laboratory by multiple compaction test among others. The result have from this test shall be used to determine the characteristic properties of the selected sample as well as to design for its mixing proportion when needed for civil engineering projects 1.2 AIMS AND OBJECTIVES AIMS T he aim of this research work is to determine the effect of Groundnut shell ash on lateritic soil properties so as to determine the best mix design. OBJECTIVES - To determine some physical properties of the lateritic soil by adding Groundnut shell ash as alternative binder in order to check for suitability for road construction in any civil engineering project. - To determine the effect of Groundnut shell ash as pozzolanic materials on lateritic soils. - To determine the suitability of the modified soil on civil engineering project 1.3 SCOPE AND LIMITATIONS SCOPE The scope of this project includes the following: - To determine the strength and bearing capacity of the selected lateritic soil sample. - To determine the suitability properties of the soil sample on civil engineering project. - To determine the index properties of their selected soil sample according to AASHTO soil classification scheme. LIMITATIONS This research is limited to the determination of effect which Groundnut shell ash has on lateritic soil properties if used as an alternate binder in any civil engineering project. 1.4 METHODOLOGY The methodology of this research work involves: - Collection of laterite soil at specified site, dry it and cruch it to allow pass 20mm sieve. - Collection of Groundnut shell and burn it to ash in order to obtain Groundnut shell ash and sieve it to pass 75mm or 0.075mm. Aparture before use. - Carryout various laboratory test on lateritic soil properties e.g. sieve analysis, C.B.R test, compaction test, specific gravity test, liquid limit and plastic limit test among others. - Addition of Groundnut shell ash in various proportions i.e 2%, 4%, 6%, 8% to lateritic soil properties and carry out laboratory test on it (C.B.R Test, Compaction Test, e.t.c) 1.5 JUSTIFICATION The justification to this research work the effect of Groundnut shell ash on lateritic soil properties shall be determined through various laboratory test which will enable us to know if the addition of groundnut shell ash as an alternative binder in laterictic soil properties is good and if it can be use in any civil engineering project.
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