Recycled tires offer polypropylene fibers from the reinforcement fabric to increase the fire resistance of the concrete

According to a study by the University of Sheffield, the use of polypropylene textile reinforcement (fber) present in recycled tires helps concrete structures better withstand fire.

That the use of polypropylene (PP) fibers in the concrete mixtures used for greater fire resistance was a well-known practice is not new, interesting thing from the point of view of the circular economy , is that the reinforcement fabric contained in recycled tires it has been studied to understand its fire behavior in a concrete structure.

The use of polypropylene fibers, in particularly fire-resistant concrete recipes, is indicated to reduce the phenomenon of conglomerate explosion under the effect of heat.

The study has shown that the use of recycled PP fibers , in this case from recycled tires, does a job equivalent to virgin fibers, with savings in energy and natural resources for their production.

But what is the advantage of using recycled PP fibers in the event of a fire?

The concrete structure, under the effect of fire, considerably increases its temperature and, due to the humidity trapped inside, given by the ratio of water and cement during the formation of the structures, it could detonate concrete parts in an attempt to leave the hotel.

In this case, the PP fibers, during the heating of the structure , gradually dissolve , creating a network of micro tunnels that allow moisture to find leaks to the outside.

One might think that the creation of these micro pathways could reduce the mechanical strength and rigidity of concrete, but in reality the volume of the fibers is so limited that it does not affect these factors according to the University of Sheffield.

The use of recycled PP fibers not only has the function of protecting concrete from explosions caused by humidity trapped inside, but also of protecting reinforcement rods . In fact, these, if they were in contact with the surfaces in direct contact with the heat source due to the loss of the concrete covering layer, would undergo rapid structural deteriorations.

The only purpose of adding recycled PP fibers is to dissolve them when needed, reducing the internal pressure of the conglomerate.

The studies will continue with the aim of testing different types of cement mixes, with different grain sizes of aggregates, subjected to different temperatures, with the aim of studying, at the microstructure level, the damage caused by fire and structural changes.

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Automatic translation. We apologize for any inaccuracies. Original article in Italian.