Assessment of concrete production processes and the rate of concrete quality for building construction in the case of jimma town

Abstract

Concrete is a composite material composed of aggregates (fine and coarse) bonded together with fluid cement (hydraulic cement and water) that hardens over time. The production of concrete passed through various stages. These are batching, mixing, transporting, placing and compacting, finishing and curing. Concrete production is time-sensitive. Once the ingredients are mixed, workers must put the concrete in place before it hardens. Inconsistency or variability of concrete production processes, which have significant impact on the quality of concrete, seen in the building construction projects.Lack or absense of detailed study conducted in Jimma town was the principal/driving factors to undertake this research on the area. This paper focused on the assessments of concrete production processes and the rate of concrete quality in building construction projects. The assessment pointed on twenty five building project (private and government), which were under construction, found in Jimma town. This paper conducted by distributing questionnaire to the contractors and consultant engineers and by carried out physical observation on the active projects. Statistical method used to analyze information gathered through primary and secondary sources. Poor practice of concrete production processes observed and it have great gaps from the specified requirements and standard codes. It was found out that 52 percent of the projects contain defective lots as per the EBCS, as per the American Standard 24 percent have defective lots and as per British standard 40 percent have defective lots. It’s concluded that adequate concrete ingredient tests were not conducted. And also tests like soundness and chloride content not conducted at all. Analyses carried out on the investigated projects clearly showed us lower rate of concrete quality. Not only improving the quality of workmanship but also non-intermittent concrete ingredient tests recommended for all projects. Hence, a great deal required from Jimma town construction office, contractors and consultants to improve quality of concrete in building construction.