The UK Waste and Resources Action Programme (WRAP) and the University of Sheffield, in collaboration with some 25 industrial partners, have funded the University's Centre for Cement and Concrete to carry out two major investigations - with a total value of around £1.2m - into the potential for using waste glass (cullet) as a high-value ingredient in concrete.

It is hoped the projects - known as ConGlassCrete I and ConGlassCrete II - will lead to waste glass being used in a wide range of products. The projects are especially focused on developing cullet as a decorative, exposed or polished aggregate finish in bespoke concrete products, and as a high-value cementitious material that will reduce consumption of Portland cement. Other potential applications being explored include as fibre-reinforcement, or general low-value aggregate, for concrete.

This important R&D work is a response to EU pressure to increase reuse of container glass, and comes ahead of legislation on recycling car windscreens and laws governing end-of-life vehicle glass, light bulbs and glass fibres.

ConGlassCrete I (which focuses on mixed container cullet) aims to:
increase container cullet recycling at national and regional levels
develop partnerships that effect changes in attitude, working methodologies and raw cullet materials usage
develop markets for recycled container cullet in the concrete products industry and to facilitate additional accredited re-processors for Packaging Recovery Notes (PRNs) encourage profit-share
facilitate the use of ground container cullet as aggregate and cement in concrete
write product-specific technical specifications based on the project research
propose amendments to the standards for aggregates and cementitious materials to accommodate glass as a fit-for-purpose material in concrete products
disseminate the results of this study to industry through two National Seminars, published papers and a dedicated web-site
compile a well-targeted, national associate partnership to this project
ConGlassCrete II aims to:
scope and develop market opportunities for businesses in the flat glass, end of life vehicle glass, glass fibre and light bulbs industries
extend the research work of ConGlassCrete I on container cullet to these additional waste glass streams
initiate a long-term 'glasscrete' testing programme
initiate product certification processes for ground cullet and glass from other waste streams for use as a pozzolanic cementitious material*(a fine siliceous material that, in the presence of moisture, reacts chemically with calcium hydroxide to form compounds possessing cement-like properties) for concrete
initiate product certification processes for concrete products containing ground and crushed glass
link with other WRAP glass projects to extend the intelligence on glass waste arisings, processing techniques and end uses communicate with architects, local authorities and pre-cast products companies to investigate the potential for using glass concrete products in high profile projects with emphasis on decorative finishes
disseminate the findings of this study by report, publication, seminar and web site
The projects - which will run until March 2004 - have won support from a significant proportion of the UK's pre-cast concrete industry and research and certification bodies. They are also being backed by the cement and cementitious materials industries, environmental bodies, waste glass producers, collectors and processors, and producers of pre-cast and ready-mix concrete. WRAP is providing £947,000 of the total funding, with a further £140,000 of in-kind funding from the University.
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