A study to investigate the cost versus quality of already mixed concrete and on-site mixed concrete in the central region

Abstract

With increasing cost of construction projects in the country, there is need to diverse means of cost reduction without compromising quality of the final product. This research takes an in-depth investigation at one of the most cost consuming items on most projects which is concrete in terms of the cost and quality of on-site mixed and Ready-Mix Concrete. The study took into account random sites within the central region using either types of concrete putting into consideration three class of concrete which were Class 15, Class 20 and Class 25. It was evident that at low intended class of concrete considered to be Class 15, the intended strength was achieved at all the sites and as the class of concrete increased the reliability that on-site mixed concrete would achieve the intended strength varied from site to site as compared to the sites which used Ready Mix Concrete where all the sites attained their intended strength irrespective of the class. As regards cost incurred per cubic concrete, the research showed that with low quantities of concrete to be cast on a specific site, onsite mixed concrete was cheaper to use as compared to Ready Mix Concrete however with increase with volumes the use of Ready Mix Concrete provided cheaper relative to the other type. This study recommends the use of on-site mixed concrete on sites where the intended strength of concrete is low and expect low quantities to be cast but with increase in intended strength and volumes to be cast it would be better to use Ready Mix Concrete.