Recycled tyres can protect concrete from damage in fires

University of Sheffield researchers have found that recycled tyres can be used to prevent protect concrete from a fire.

Concrete flooring is the main type of flooring used in industrial premises because it is both cost effective and hard wearing. If the building catches fire, concrete does not burn but tends to spall, surface layers peel off and there can be explosive cracking.

To stop concrete spalling, manmade polypropylene (PP) fibres can be added. The Sheffield research is the first time that these fire protection fibres have been made from recycled rather than raw materials.

The results of the Sheffield research were published in the Fire Technology journal. Its main author, Dr Shan-Shan Huang of the Sheffield University Department of Civil and Structural Engineering, said:

“We’ve shown that these recycled fibres do an equivalent job to ‘virgin’ PP fibres which require lots of energy and resources to produce. Using waste materials in this way is less expensive, and better for the planet.”

Under intense heat, the fibres made from recycled tyres melt and leave small channels, allowing water trapped inside the concrete to escape instead of remain and cause explosive cracks. These channels are so tiny that they have no effect on the strength and stiffness properties of the concrete.

The research team has been working with Sheffield company Twincom and is still experimenting with different ratios of fibres to concrete before the new fibres can be used in a commercially available process.