Reusing fibrous materials from tyres in concrete has been found to reduce spalling where concrete explosively cracks under intense heat.
University of Sheffield researchers have found that reusing the textile reinforcement from old tyres helps to prevent layers of concrete shattering off under heat stress.
Under intense heat, expanding moisture inside concrete causes fragments to break off – potentially causing significant structural damage.
If concrete is mixed with the fibres, the heat melts them leaving tiny channels in the concrete’s structure that allow the expanding moisture to escape without fracturing it.
The fibres are small and do not affect the concrete’s strength or stiffness.
Man-made polypropylene fibre is commonly used in concrete to prevent spalling. This study is the first to show that the using reclaimed materials can have the same effect.
The textile fibres are added to tyres to increase their strength and performance. They can be removed from the rubber of worn out tyres.
University of Sheffield Department of Civil and Structural Engineering senior lecturer and lead author of the research Shan-Shan Huang said the recycled fibres do the same job as polypropylene fibres, but do not require energy to produce.
“We’ve shown that these recycled fibres do an equivalent job to ‘virgin’ polypropylene fibres which require lots of energy and resources to produce,” she said. “Using waste materials in this way is less expensive, and better for the planet.”
The University of Sheffield plans to continue testing the material with different fibre to concrete ratios, and using different types of concrete.
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