Recent trials at RMIT University investigated the usage of textiles in concrete. Surprisingly, over 70% of textiles can be used in concrete. This means that even some of the most un- recyclable materials like fire-fighter gear can be used. This is significant because recycling these materials causes a reduction in landfill and pollution. By using fibrous materials and textiles, the concrete is essentially ‘bound’ together, avoiding cracking and breakages.

Cracking in concrete occurs when water from the concrete evaporates causing it to shrink. This process is called shrinkage cracking. By putting to work the textiles in the concrete, it pulls the concrete together causing the concrete to stay intact without cracking. Currently, steel fibres and wires are used in concrete as a binder. However, as the steel is solid there is no stretch, causing cracks.

The textiles are separated into their strands and are then cut into 12mm lengths. This then creates small enough strands to be able to mixed into the concrete when being poured, allowing for the ‘binding’ process to begin. “We identified this is the best length that gave the optimum condition, or the maximum crack resistance,” says Dr Chamila Gunasekaran a researcher on the topic at RMTI university.

 The team of engineers at RMTI university originally trialled the process using discarded old clothes from charity shops.  

 “Then we thought: why we can’t use this the same principle for other [wastes], like carpet waste?” says Gunasekara. Old carpet and rugs are one of the hardest materials to break down as there are many different textiles used in the process of carpet making. Being able to recycle old clothes would mean that they would not end up in landfill.

The process of selecting fibres and textiles must be simple in order to be economically sufficient and reduce separation costs.

“The other thing is material supply chain. If we focus on only one single material, then the question is whether we have enough materials to progress the concretes – not only in our research, but in construction prospecting,” says Gunasekara.

The team’s hope for the future is to implement this fibrous binding method into everyday concrete using recycled materials to put the world one step closer to being land fill free.