Epistemics in Science, Engineering and Technology, Vol.1, No.2, 2011, 89- 94 O. Joshua & P. O. Law al 89 Cost Optimization of Sandcrete Blocks through Partial Replacement of Sand with Lateritic Soil O. Joshua 1 and P. O. Lawal 2 1 Department of Building Technology, Covenant University, Ota. Ogun State; Nigeria ope.joshua@covenantuniversity.edu.ng GSM: +234 803 612 8251 2 Department of Quantity Surveying, Federal University of Technology, Minna. Niger State;Nigeria lawalp@futminna.edu.ng or lawalp4christ@yahoo.co.uk GSM: +234 803 453 1271. Abstract This work finds a way in which lateritic soil within Ota, Ogun State of Nigeria could be used in the production of hollow sandcrete blocks. This replacement is intended to develop more economic sandcrete blocks since the cost of lateritic soil in Ota is much less than the cost of the conventional fine aggregate used in the production of sandcrete blocks without compromising the intergrity of the blocks. It was deduced from literatures that inclusion of lateritic soil in sandcrete block production results in a lesser quality blocks. However, this work found the maximum permissible replacement that still makes the blocks to be within the recommended standard. The blocks were produced with each lateritic soil sample from different sources replacing sand in steps of ten percent to 60% and their compressive strengths determined and compared with that of a standard sandcrete block to check for the acceptable percentage replacement. In the compressive strength test, 72 numbers of 225 x 225 x 450mm hollow laterised sandcrete block sizes were produced, cured and crushed to determine their twenty-eight-day compressive strength. Cost analysis was performed discovered that the inclusion of the lateritic soil saves the cost of production by 11.89%. This percentage replacement can be recommended to the block moulding industries within Ota with a view to reducing the production costs of the blocks. Keywords: Economic block, laterized brick, laterized sandcrete block, lateritic soil. 1. Introduction. A major factor affecting the construction industry in developing countries is the cost of building materials most of which have to be imported. Frequent increases in prices of building materials across Nigeria has reawakened serious awareness to relate research to production, especially in the use of local materials as alternatives for the construction of functional but low-cost dwellings both in the urban and rural areas of Nigeria. One such local material that is being researched is lateritic soils. Lateritic soil has been one of the major building materials in Nigeria for a long time. The main reason is because it is readily available and the cost of procuring it is very low. Lateritic soil has 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 advantages include non-requirement of specialized skilled labour for the production of laterized sandcrete blocks and for its use in the construction of structures. Laterized concrete structures are known to have potentially sufficient strength compared with those of normal concrete. This study is part of the continuing effort to investigate the properties of lateritic soils, stabilized or unstabilized, reinforced or unreinforced, with the view to improving such properties. Specifically, the study looks into the effect of replacement of the conventional fine aggregate, sand, with lateritic soils within Ota on the compressive strengths of laterized sandcrete blocks with the purpose of reducing its unit cost of production. Sandcrete blocks are constructional masonry units that have been generally accepted to the extent that when an average individual thinks of building, the default mindset is the use of sandcrete hollow blocks. Sand, the main constituent of sandcrete block, is, according to Sengupta (2008), a natural product obtained from riverbeds, the mining of which is expensive. This ‘cost’ aspect is why this research explores cost reduction options without compromising quality by way of using mixtures of sand and laterite in block moulding. Cost reduction which leads to cost optimization is one of the most crucial aspects of construction project planning which Shi et al. (2009) and Wu and Lo (2009) regarded as a multi objective optimization problem. Laterite, derived from the Latin word”later” is essentially the product of tropical weathering. It is usually found in hot and wet tropical areas where natural drainage is impeded (Lasisi and Osunade, 1984; Wikipedia, 2003). From an WebsJournals Epistemics in Science, Engineer ing Epistemics in Sci ence, Engineering and Technology, Vol.1, No.3, 2011, 89- 94 and Technology