Assessing the Influence of Variations in Chemical Composition of Cement Brands in Ghana on their Setting and Workability of Concrete

The reliance on inferior on cement products for the construction of housing projects and other civil engineering infrastructural facilities has led to a number of building and other structural failures in Ghana over the years. The manufacturing of concrete utilized in the building of various structural member, such as columns, beams, slabs, footings and wall, was negatively impacted by the use of low-quality cements, rendering them unable to sustain any loads placed on them. Another observation made from the cement used was the inadequate proportioning of the chemical compounds during the manufacturing process which has negatively affected the setting of the concrete contributing to poor performance of structural elements in buildings and other infrastructural projects. In this research, the impacts of the variations in chemical constituents including SiO2, Al2O3, Fe2O3, Na2O, K2O, CaO, MgO, and SO3 in the different brands on setting times of cement and workability of fresh concrete were examined. The Vicat apparatus and the slump apparatus set-ups were used to measure the setting time and concrete workability respectively. It was found that the majority of the chemical compounds of the various cement brands evaluated in this research provided appreciable setting time as well as typical and acceptable consistencies. Most cement brands showed initial and final setting times between 30 and 271-306 minutes for cements in the 32.5R class. The initial and final setting times generated by the test were likewise observed to fall within 30 minutes and between 172-263 minutes, respectively, in the 42.5R class of cements, where a similar pattern was also observed. It was noted that for the same water-cement-ratio in all the concretes from the different brands of cement, good workability was obtained.