1. Introduction

           Glass is produced in many forms, including packaging of container glass (bottles, jars),

flat glass (windows, windscreens), bulb glass (light globes), cathode ray tube glass (TV screens,

monitors, etc), all of which have a limited life in the form they are produced and need to be

reused/recycled in order to avoid environmental problems that would be created if they were to

be stockpiled or sent to landfill.    

          Recovered waste glass can be infinitely remelted without degradation of its physical

properties and, theoretically at least, the glass manufacturing industry could use 100% recycled

glass as a primary feedstock. However due to tolerances on contamination there is a practical

limit and it is estimated that approximately 650,000 tonnes/year of waste container glass cannot

be recycled into new glass manufacture. There is also arising of over 1million tonnes/year from

other waste glass streams (e.g. plate glass, windscreens and lighting) that could be recovered and

re-used. While some markets for recycled waste glass already exist in construction (170,000

tonnes as aggregate in asphalt, pipe bedding, backfill, loose fill, decorative aggregate and golf

bunkers), there is a huge potential for this to increase in the concrete construction sector.

          Published research work in the UK, USA and other countries since 1997, has shown that

finely-ground waste glass will react in a pozzolanic manner in cementitious systems and

contribute to the strength development of concrete. This means that raw post-consumer glass

could be processed and used to replace a percentage of the Portland cement in concrete mixes.

Considering the size of the cement industry (over 10 million tonnes/annum in the UK) this would

appear to be a potential high volume, economic and environmentally friendly solution to part of

the waste glass problem.

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