Cement and Concrete

Recycled glass may be used as a coarse or fine aggregate, or as a partial cement substitute in a wide range of concrete-based products.

WRAP has sponsored some major studies into this topic through the Universities of Sheffield (the ConGlassCrete project) and Dundee (the GlassAggregate project).

The ConGlassCrete work consisted of two projects which investigated the risk of alkali silica reaction (ASR) and its mitigation, the practicalities of glass addition, mechanical proporties, pozzolanic effects when added as a fine powder. It has also led to the publication of a pre-certificatioin report from BRE, confirming the suitability of recycled glass as a pozzolan.

The Dundee project assessed the viability of using borosilicate glass in concrete and provided an assessment of the best practical environmental option (BPEO) for the use of recycled glass in concrete.

Main benefits:

Reduces continued exploitation of primary aggregate sources (sand)
Excellent contribution towards Sustainable Buildings Task Group target of 10% recycled content

Further resources

BRE - Final Report - The use of Glass as Aggregate in Concrete. GLA0046 3548 kb
This final report presents the monitoring results obtained in the two years since specimens were cast and put on exposure sites or into accelerated test conditions. It also includes an interpretation of the effectiveness of the various suppressing materials (metakaolin, pfa, ggbs and powdered glass) on ASR expansion.
ConGlassCrete 1 - Final Report 3037 kb
The final report of the first phase of ConGlassCrete project
(Other keywords: specifying construction materials and products, recycled content, concrete)
ConGlassCrete 2 - Final Report 572 kb
The final report of the second phase of the ConGlassCrete project
(Other keywords: specifying construction materials and products, recycled content, concrete)
Promoting best practicable environmental options for the commercially sustainable use of glass cullet in construction 1087 kb
This report contains the results of a study carried out as part of a research project, one objective of which was to establish the Best Practicable Environmental Options for using processed glass cullet in construction applications.
(Other keywords: specifying recycled content, construction materials and products)
INSTARMAC - Final report - Full Scale Operational Trials using Recycled Glass in Selected End Markets: using recycled glass in cementitious products. GLA044-014 1275 kb
The Instarmac Group plc Board of Directors and employees has embraced the opportunity provided by WRAP to continue its push to develop environmentally friendly products. Instarmac Group plc with the support of WRAP have conducted operational trials on 6 cementitious high value bagged products, 1 resin based repair mortar and 1 polymer modified tile adhesive using recycled glass sand to replace silica sand within these products.
BRAND AND RAE - Final Report. Full Scale Operational Trials involving the use of Recycled Glass in the Manufacture of Concrete Blocks. GLA44-055 520 kb
This project seeks to determine into which products and at what level it would be most advantageous to use crushed recycled glass in concrete blocks.