The use of excavation waste for the production of concrete products

Abstract

This dissertation aims to tackle the problem of construction and demolition waste on the island, with an emphasis on excavation waste, and how this can be put into good use in the production of concrete products. With several large-scale projects underway, and several others set to start soon, both the generation of more excavation waste, as well as the demand for more concrete products, will surely increase. This scenario, backed by ever-growing construction industry, and the continuous problem of how to dispose of such waste resources, bring about an urgent need to find a long-term solution for this problem. In this study, the author proposes the replacement of cement in a concrete mix with crushed limestone. The material proposed for the replacement is crushed Globigerina and Coralline limestone, currently being excavated to form the Ghallis Engineered Landfill at Maghtab. The dissertation also looks at the local geology and the possible resources it can offer, as well as the waste scenario, with an emphasis on waste generated from the construction industry. Re-processing technologies are then also discussed, and how these can be used to process excavation waste. A brief overview of cement technology is also given, as is relevant to this study. A study of the limestone to be used was carried out, and a mix designed to be used for the assessment of the effect of limestone replacement of the cement. Concrete cubes and beams were cast at the laboratory, and all the required tests were performed on the samples. On the basis of the results obtained, a cost analysis study was carried out, to determine the governing cost factors in such a production process, and to determine the feasibility of any possible use for this vast resource.