ECONOMIC AND ENVIRONMENTAL IMPACTS OF CONCRETE SUPPLY SYSTEMS: CASES OF BUILDING PROJECTS IN ADDIS ABABA

Abstract

Thorough understanding on the impacts of concrete supply systems is vital in enhancing economic efficiency and achieving overall competence of a particular construction project. Concrete being one of the main building materials is supplied to construction projects by means of two systems in Addis Ababa: Ordinary (onsite production) and Just-in-time. Most of the construction projects had some veracious intentions for selecting the distinct concrete supply system whereas few of them preferred arbitrarily. However, only few of them have attempted to pre-evaluate the economic importance of using the particular concrete supply yet most of them didn‟t notice the environmental impacts of the supply systems well. Besides this, there is a critical shortage of written documents in the area of supply systems and the environment. This research aimed at investigating the economic and environmental impacts of the concrete supply systems used in building projects in Addis Ababa in order to recommend suitable supply alternative in different circumstances and suggest possible ways to alleviate the harmful impacts. The research was conducted taking twenty building projects as cases of the investigation, ten for each concrete supply. These cases of the research were analyzed under the identified variables of the study, economy and environment, using methods of comparison. The environmental impacts of the supply systems are examined in terms of ecosystems, natural resources, and public impacts. The economic impacts are also considered under the direct, indirect and induced impacts of the supply systems. Ordinary concrete supply was observed benefit able in production costs initially while Just-in-time supply was witnessed to minimize additional costs incurred to a project due to holding materials. Similarly ordinary supply created more direct employments whereas JIT supply inclined towards generating more indirect employment opportunities. Hence construction projects are recommended to carry out exhaustive economic and environmental pre occupation analyses before executing projects. These outputs of the research are important to the construction companies, workers at the projects sites, owners, the government and the community as a whole.