Mix design proposal for structural concrete using messobo ordinary portland cement
Mix design is a process in which one determines the relative quantities of the ingredients prior to mixing to produce the desired quality of concrete. By varying the mix proportions of the ingredients, different strength grades of concrete can be obtained. Several factors, which include water cement ratio, workability, curing type and duration, sizes of coarse aggregate, and sand silt content are among the several factors attributing to the quality of concrete. In this paper, attempts have been made to provide mix design proposals considering the most important factors contributing to the quality of concrete. Fxtensive concrete mix preparations were made to obtain concrete strength grades up to C-45 using .Hessebo Ordinary Portland Cement (OPC). Realizing the various factors contributing to the quality of concrete, 43 trial batches of different mix designs were investigated. Based on the test results, equations were derived to relate compressive strength to w/c and to predict the 28 days compressive strength from the 7 days compressive strength. In all cases, Messebo OPC was used and the results show that it can be used to produce concrete grades of higher quality (up to C-45) for the construction industry of normal practices.
Key words: Aggregate, Compressive strength, Concrcte, Curing, Mix proportion, Portland cement, Tensile strength, W/c ratio, Workability.