The University of South Australia, with Tyre Stewardship Australia funding, has been working on a project to develop and test reinforced Crumbed Rubber Concrete (known as CRC) for use in Australia’s vibrant residential construction industry. This adds to the range of ongoing research into the use of rubber in concrete.
Positive Outcome for Rubber in Concrete
Nearly 40 per cent of the annual total of approximately 9.6 million cubic metres of Australian pre-mixed concrete is used for residential construction. That volume presents a significant opportunity to consume very substantial quantities of recycled rubber and could account for a large proportion of the 56 million end-of-life tyres Australia generates each year.
CRC is made when crumb rubber, from end-of-life tyres, partially replaces sand in the concrete mix. The testing program has covered assessments of both the material and its structural properties and, to date the results have been very encouraging.
Interestingly there is conflicting research in the outcome of crumb rubber use in concrete, but any move towards a positive use is good news.
Generally, CRC showed no difference in performance when compared with conventional concrete in the full-scale trial residential slabs constructed at the university. There were no issues related to the mixing and delivery of CRC by a commercial ready-mix supplier and the residential slab contractors working with the new product, reported easy application and no difference when finishing the concrete surface. In addition, as with conventional concrete, no visual deterioration was observed on the rubber concrete slab surface after 3 months. All the initial results indicate that CRC in residential slabs is a promising and potentially viable alternative to conventional concrete.
The research has also determined that preparation of the crumbed rubber used need not be a costly and time-consuming exercise. Only requiring simple preparations, such as washing the rubber, dry mixing it with cement, and a slightly longer mixing time. All producing a very robust product at no additional cost.
The commercial potential for CRC is considerable given that it has already demonstrated a range of positive properties, including increased toughness and impact resistance, reduced tendency for cracking and shrinkage plus better acoustic and thermal insulation presented in other studies.
The technical research and testing work by the University of South Australia will continue as further applications and performance characteristics are investigated. That work will be accompanied by field and commercial testing that will provide greater assurance and guidance, supporting increasing opportunities for the construction industry to use CRC.
The initial positive results have been welcomed by the TSA CEO, Lina Goodman, as an example of the organisation supporting research and development that will drive greater domestic use of recycled tyre-derived material.
“Given the ongoing population growth that is sure to sustain a growing domestic construction industry, the work we are supporting on the development and testing of CRC is one of the most promising areas of market development. Ultimately, the aim is to find valuable uses for tyre-derived material that generate a strong domestic market, create a value for the resource and, in that way, deliver a sustainable circular economy outcome.”
Source: Tyre Stewardship Australia