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MATHEMATICAL MODEL ANALYSIS OF QUALITY OF CONCRETE PRODUCED IN THE WARM-HUMID CLIMATIC ZONE OF SOUTH EAST, NIGERIA
*Odoanyanwu Ndubuisi M., Ivokeifeanyichukwu H. and Barnaby Jude I.
In construction industries, noncompliance to existing standards has been one of the major causes of substandard material production and to an extent poor housing development. It has therefore degenerated to the inability of dictating standards with the performances of building materials in the industry. The threat of this ugly situation grows higher when materials of composite natures are involved. In this era of innovation in the construction technology generally, the study focuses onproviding a more reliable and faster means to producing cement concrete cubes and sancrete blocks of desired properties starting with Warm Humid Climatic (WHC) zone of Nigeria. In the beginning, field survey method was adopted to obtain information on a prior knowledge of the common nominal mix ratio used in producing cement concrete cubes andsandcrete blocks in the area. The information was used as a basis for designing the cement concrete cubes and sandcrete mixes using BoxWilson symmetric Composite Plan Bm.Laboratory experimental tests were carried out on the blocks produced with the various mix designs to obtain values on their density and compressive strength properties. Polynomial regression models were therefore developed, and subsequently tested to certify their fitness considering only the independent variables (cement, water, and sand aggregates) that are significant for the respective properties. Monofactorial effects of the variables were investigated on the properties to ascertain the degree of their influence on the respective properties. Progressively, optimal equations of the final regression models were therefore developed having optimized the respective significant variables in the models, using the quadratic equation for blocks of optimum and desired performances. To this end, nomograms were therefore constructed with the optimal values derived from the optimal equations to reflect various optimum compositions of the constituent ingredients (variables) for certain desired properties of the blocks, depending on the functional requirements or purposes of use. In the light of this rare development, speedy decisions productions of the blocks of desired properties will be possible and accurate. Production of the targeted properties of the blocks would therefore, not be hindered by the limited quantity of any of the ingredients, since there are possibilities of other optimum compositions that would accommodate the limitation in quantity of the said ingredient.[Full Text Article]