THE STRENGHT OF BLOCKS MADE FROM (1) CEMENT AND LATERITIC SOIL (2) CEMENT AND RED EARTH (3) LATERITE, SAND AND RED EARTH

ABSTRACT

In recent years, the attention of most researchers is shifting towards the optimization of building materials by using local contents, the use of indigenous materials, and local industrial by-products unique and abundant in certain localities. This study investigates the effect of sand utilised in cement–laterite block production in Nigeria.  Cement-laterite blocks were made with lateritic soil replacement with conventional fine aggregate from 0% to 25% by weight with Hydraform block moulding machine. Cement-laterite blocks without sand (0%) served as control. The blocks produced were tested to determine their density, compressive strength, tensile strength, water absorption, erosion and EDS/SEM properties. The average density of cement-laterite blocks indicated that as the curing days increase the density decreases alongside for each percentage of sand content decreases. The results of both the compressive and tensile strength were almost the same because only 5% sand replacement achieved the maximum strength above the 0% (control level) and the rest were below the control level or 0% from 7 days to 28 days curing period. Water absorption test results after 28 days curing period increased as the sand percentages increased. Erosion test result after 28 days curing period showed increase erodability as the sand percentages increased.  The EDS results test indicated he chemical elements of the block such as O, Ca, Si, Al, and Fe. Lastly, the SEM images of the various percentages of sand showed some pores present in the cement–laterite blocks. Therefore, it can be concluded that the sand replacement laterite blocks have the potential of supporting the affordable housing concept in Nigeria. The study recommends 5% sand replacement of laterite in producing cement–laterite blocks.

 

CHAPTER ONE

INTRODUCTION

 

1.1 Background of the Study

In the world today, there are some basic necessities one cannot live without such as food, clothing and shelter. However, the cost of shelter takes the most part of one’s income. In recent years, homeownership for the middle and low-income earners of the society is turning to be a mirage as building materials, construction costs and other factors have constantly put housing development at a very high cost. In developed countries, accommodation and homeownership are easier as governments and financial institutions have planned effective housing policies and programmes to aid the citizenry in homeownership at affordable rates (Adebakin et al., 2012). In the developing world, especially in metropolitan African cities, scarcity of living accommodation has always been an issue. According to Adebakin et al. (2012), the available housing stock is diminishing by the day due to the high level of rural drift to urban centers. Checking scarcity and high cost of building materials and the need to drastically reduce critical housing shortages, especially in the urban areas (and developing modern housing setups in the rural areas), have encouraged the search for alternative, innovative and costeffective building materials. Aside from concrete that is a major component of buildings and other engineering structures, sandcrete blocks form a major part to be recognized and put under consideration. One of such local materials that are being researched is lateritic soil. Lateritic soil has been one of the major building materials in Nigeria for a long time. The main reason lies on the fact that it is readily available and the cost of procuring it is relatively low.

Lateritic soil possesses other advantages which make it potentially a very good and appropriate material for construction, especially for the construction of rural structures in the developing countries. These merits include little or no specialized skilled labour required for laterized sandcrete blocks production and for its use in other construction works; and laterized concrete structures have potentially sufficient strength compared with that of normal concrete (Lasisi & Ogunjimi, 1984). Lateritic soils are essentially the products of tropical weathering usually found in areas where natural drainage is impeded (Lasisi& Osunade, 1984). Lasisi and Ogunjimi (1984) assert that the degree of laterization is estimated by the silica sesquioxides ratio (SiO₂/ (Fe₂O₃ + Al₂O₃)). Silica-Sesquioxide (S-S) ratios less than 1.33 are indicative of laterites, those between 1.33 and 2.00 are lateritic soils and those greater than 2.00 are non-lateritic types.

According to Akintorinwa et al. (2012), lateritic soil abounds locally and its use is mainly limited to civil engineering works like road construction and land fill operations. It is less utilised in the building industry except in filling works. In lieu of the abundance of lateritic soils and its availability, its optimum use in building production could positively affect the cost of buildings leading to the production of more affordable housing units (Joshua &Lawal, 2011). Its use in the building production is not yet generally accepted because there are no sufficient technical data on it, hence limiting its wider application in building construction work (Udoeyo et al., 2006). Studies by Adepegba (1975) and Osunade (2002) used lateritic soil in concrete production where laterite was made to partly or wholly replace conventional fine aggregate in the production of concrete known as laterized concrete; and in the production of brick units such as Compressed Laterized Brick (CLB) usuallystabilised with cement. Presently, these applications are mostly limited to buildings in rural areas and low income housing projects which are mostly situated at satellite areas (outskirts) of Central Business Areas (CBA’s).

Laterite is described as a product of in-situ weathering in igneous, sedimentary, and metamorphic rocks commonly found under unsaturated conditions (Rahardjo et al., 2004). Lateritic soil is one of the most important and common materials used in earthwork engineering construction in the tropics and subtropics where it is in abundance. The name laterite was coined by an English surgeon Francis Buchanan in

1807 in India from a Latin word “later” meaning brick in the 19^th century (Thomas, 1996). He coined the term laterite when he wrote “What I have called indurated clay is one of the most valuable materials for building. It is diffused in immense masses, without any appearance of stratification and is placed over the granite that forms the basis of Malayala (Thomas, 1996).It is believed that this work will contribute to the few existing studies on the use of lateritic soil in building production. Laterite, such as particle size, Atterberg’s limits, moisture content, grain size among others which in turns affect the strength of laterized products. (Middendorfet al., 2003).  Different methods have been used in laterite stabilization in recent years, mechanical and chemical stabilization being the two most popular methods in operation all over the world. Laterite stabilization using mechanical approach involves blending of different grades of soils to obtain a desired standard.

 

These properties can however be improved through stabilization in order to improve the characteristics and strength. O’Flaherty (2002), Villar-Cocina et al. (2003) and Amu et al. (2011) described soil stabilization as any treatment applied to a soil to improve its strength.

However, earth brick/brick buildings have been built for thousands of years, and there is a strong tradition of earthen structures on the African Continent. Traditional mud huts were the most common form of building before the advent of modern architecture and planning. Earth brick or brick buildings still shelter more than a third of the world’s population. Recently there has been a worldwide resurgence of interest in earth building, especially in developing countries where local earth is the most accessible source of building material. However, most soils do not contain the mix of clay, silt and sand required for good earth building (Roux & Alexander, 2007).

 

1.2 Statement of the Problem

Recently, the attention of most researchers is shifting towards the optimization of building materials by using local contents; the use of indigenous materials; and local industrial by-products unique and abundant in certain localities. This study therefore explored ways in which sand could be utilised in cement–laterite block production in Nigeria. One of the early works on laterite was by Adepegba (1975) who compared the strength properties of normal concrete with those of laterized concrete. He found that concrete with laterite and fine sand can be used as a structural material in place of normal concrete. Osunade (2002) studied theeffect of replacement of lateritic soils with granite fines onthe compressive and tensile strengths of laterized concrete.Lasisi and Osunade(1984) investigated the effect of grain size on the strength of cubes made from lateritic soils.  They established that for lateritic soils to be of economical use in the industry, the range of particle sizes used in moulding blocks must tend towards the silt fraction. Joshua et al., (2014) also investigated the effects of partial replacement of sand with lateritic soil in sandcrete blocks. There is however a limited empirical literature on the use of sand as a partial replacement of laterite to produce salancrete blocks. This study therefore fills this gap by investigating the effect of sand on the properties of cement- laterite blocks.

 

1.3 Aim

The aim of the study is to determine the effects of sand on the properties of cement- laterite blocks.

 

1.4 Specific Objectives

In other to achieve the aim of the study, the specific objectives are:

• To determine the density of cement-laterite blocks produced from sand as partial replacement of laterite.
• To determine the compressive strength of cement-laterite blocks produced from sand as partial replacement of laterite.
• To determine the tensile strength of cement-laterite blocks produced from sand as partial replacement of laterite.
• To determine the water absorption of cement-laterite blocks produced from sand as partial replacement of laterite.
• To determine the erosion resistance of cement-laterite blocks produced from sand as partial replacement of laterite.
• To determine the Energy Dispersive X-Ray Spectroscopy (EDS) and Scanning Electron Microcopy (SEM) of cement-laterite blocks produced from sand as partial replacement of laterite

 

1.5 Research Questions

• What is the density of cement-laterite blocks produced from sand as partial replacement of laterite?
• What is the compressive strength of cement-laterite blocks produced from sand as partial replacement of laterite?
• What is the tensile strength of cement-laterite blocks produced from sand as partial replacement of laterite?
• What is the water absorption of cement-laterite blocks produced from sand as partial replacement of laterite?
• What is the erosion resistance of cement-laterite blocks produced from sand as partial replacement of laterite?
• How can the Energy Dispersive X-Ray Spectroscopy (EDS) and Scanning Electron Microcopy (SEM) of cement-laterite blocks produced from sand as partial replacement of laterite be determined?

 

1.6 Significance of the Study

This study on the properties of cement-laterite blocks produced from sand as partial replacement of laterite will help in policy decision making and offer insight into the positive effects of the overall development of the materials for building.  The findings of the study will inform local craftsmen and contractors, developers and policymakers on the effects of using local materials in building houses in the communities. Also, the outcome of the study will enlighten the stakeholders in the building industry on the way forward in enhancing sustainable and environmental friendly building materials which can reduce the cost of using modern technology of building. The findings of the study equally hope to inculcate in the society the spirit of using local materials in building durable and sustainable houses.

1.7 Scope of the Study

The study was done in the Sunyani Municipality using resources available to the municipality. The samples were moulded on the Sunyani Technical University Campus and taken to the laboratory for testing.

 

1.8 Limitation of the research

The study focused on using sand as partial replacement of laterite in the production of cement-laterite blocks and conducted test to obtain the properties.The research was delayed due to time, money, resources available and logistical constraints.

The research was based on comparing the strength development of blocks

 

THE STRENGHT OF BLOCKS MADE FROM (1) CEMENT AND LATERITIC SOIL (2) CEMENT AND RED EARTH (3) LATERITE, SAND AND RED EARTH

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