DEVELOPMENT OF STABILISED LATERITE BRICKS FOR BUILDING COST REDUCTION IN SOUTH WESTERN NIGERIA.

Abstract

Housing shortage is a worldwide phenomenon among developing and developed countries. Shortage of housing has been recorded in both rural and urban communities in Nigeria especially inthe South Western part. It was in recognition of the magnitude of housing needs in developing countries that made the United Nations estimate annual construction rate of between 8 and 10 dwelling units per a thousand population as against the low level of annual production of buildings in Nigeria,estimated at between 2 and 3 dwelling units per a thousand population.

The study was designed to carry out investigations on the development of alternative building material capable of reducing the cost of building construction, thereby increasing housing stock in the South Western part of Nigeria. The specific objectives of the study include identification of laterite samples collected from eight selected sites based on geographical spread in the South-Western part of Nigeria, examining physical and chemical properties of samples collected and determining the compressive strength characteristics as well as the exact percentage of stabiliser that will be economically useful for the production of stabilised laterite bricks. Other objectives include carrying out durability tests on samples and assessing Cost Benefit Analysis of brick-walling with Stabilised Laterite Bricks, Laterite Burnt Bricks and Sandcrete Blocks.

The research methodology employed was to ascertain through field and laboratory tests, particle size distribution for the determination of the proportions of sand, silt and clay using Soil Classification Triangle Method, determination of Optimum Moisture Content (OMC) and Maximum Dry Density (MOD) at different cement/laterite mixes using the Standard Proctor Compaction Procedure and determination of structural strengths including compressive strength and durability of the bricks produced. The results of the compressive strength obtained from the bricks produced were compared with the British Standard Specification (BS2028), which specified average compressive strength for sandcrete blocks and burnt bricks, the Nigerian Industrial Standards and the Federal Ministry of Works specifications. Results of durability tests obtained were analysed at different laterite/cement ratios. Also, comparative Cost Analysis of Stabilised Laterite Bricks with the commonly used Sandcrete Blocks and Laterite Burnt Bricks were carried out to justify the use of Stabilised Laterite Bricks as an economic material for wall construction. Research findings point at ways of making construction technique less cumbersome, efficient and appropriate thus making the building ecologically sensitive and responsive. It also assists in making laterite a building material, impermeable to water, using new additives which improve its workability and durability. In addition it affirmed its strength characteristics of durability and workability when compared with the established standards of other building materials used for wall construction such as Laterite Burnt Bricks and Sandcrete Blocks in the South Western part of Nigeria.

The research therefore recommends that Stabilised Laterite Brick is cost effective in wall construction in the South Western Nigeria and since this has been established , the case for increased housing stock is 'ipso facto' established.