Abstract:
Approximately 20% of paint sold in western countries does not get used for its intended purpose, and in time much of this left-over paint ends up in land-fill as part of the household waste collection, at a significant economic and environmental cost. Whilst glass bottles can be recycled in Auckland, a large proportion of them are rendered unsuitable for recycling back to glass and this is wasteful of the resource. The use of waste or recycled materials in concrete is a topic currently being researched considerably due to the need for more environmentally-friendly concrete to minimize resource consumption, energy consumption and greenhouse-gas emissions. In New Zealand, Resene Paints Ltd has initiated a comprehensive product stewardship campaign to recover waste paint before it enters the waste stream so that it can be recycled in applications which add value for the key participants in the recovery programme, while the collaboration amongst a cohort of companies has contributed to utilising problematic waste streams in concrete which could potentially result in the viable use of waste resources into more economical and environmentally-friendly concrete. An investigation was performed on the use of paint and glass in concrete, with recovered paint used as a proprietary admixture replacement and crushed glass being used to partially replace the depleting virgin aggregates, and included a range of lab-scale and full-scale trials on the mechanical and durability properties of concrete utilizing paint and glass. The nature of the concrete microstructure and different compounds present during cement hydration were also evaluated. This study is a continuation of the research presented (“From PaintWise to PaintCrete”) at the 2011 SCANZ conference and is a progress report on the significant research findings.