Abstract
Owing to the cumulative capacity of industrial waste materials and by-products, management of solid waste is the primary concern in the biosphere. Due to the limited measure’s in the recycling and depleting landfill site space, the industrial waste has posed serious challenges on the capacity of landfill site to handle such waste. There are numerous kinds of alternative concrete materials, which had been use in the concrete as a natural sand replacement. The utilization of these waste materials as construction material will be very much essential to achieve sustainable construction. The usage of waste materials as an alternative concrete / construction material for natural sand replacement not only makes it cost-effective, but also helps in conserving the environment. One of such waste materials is Waste Foundry Sand (WFS), which is produced by metal casting industry. In South Africa, approximately 500,000 tons of WFS and in the Gauteng Province, approximately 300,000 tons of WFS is produce annually. Around 3000 tons of WFS is discarded annually by single foundry from Gauteng. Geographically, 114 of the foundry production plants situated in Gauteng alone, disposes 342, 000 tons of WFS annually.
This dissertation presents a research that studied the effect of waste foundry sand on concrete properties (strength and durability) when used as a natural sand replacement. The experimental work in this research study is categorised into two stages. The first stage dealt with study on materials description and characterisation of WFS, which included the physical and chemical properties of five WFS’s (two green sand and three chemically bonded sands) from Gauteng, South Africa to determine their conformity with applicable engineering criteria and acceptable standards when used as a replacement, to various extents, of the fine aggregate. The main properties investigated included physical properties (particle gradation, moisture content, uncompacted bulk density, specific gravity, and loss on ignition, clay content, and fineness modulus) and the chemical and mineralogical properties, using X-ray fluorescence (XRF), X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Energy / Dispersive X-ray Spectrometer (EDS) (SEM/ED) and pH scale. The second stage dealt with studies that investigated the strength properties (compressive strength, splitting tensile strength, and flexural strength), and durability properties (Oxygen Permeability Index (OPI), Chloride Conductivity Index (CCI), and Water Sorptivity index (WSI)), of concrete containing WFS as partial replacement of natural sand...
M.Tech. (Civil Engineering)