Self-Compacting Concrete Is Now Fire-Resistant As Well

Fire resistant concrete

Self-compacting concrete offers a number of advantages over conventional concrete when it comes to construction time, usage of equipment and noise pollution. However, one aspect where the conventional concrete wins with flying colors against the newer, self-compacting concrete is the ability to withstand heat. The self-compacting concrete flakes and splits when subjected to high temperatures and this shortcoming has affected its usage, however, scientists have come up with a new concrete mix that uses a unique polymer and is able to withstand high temperatures.Self-Compacting Concrete Is Now Fire-Resistant As Well

Before we move on to how the self-compacting concrete has been made resilient to fire, let’s first look at why does the concrete chip and flake. The water trapped inside the material vaporizes when it is being exposed to high temperature and thus, builds up pressure that causes the degradation of concrete resulting in splits, flakes and chips. The next logical question would be that how come the conventional concrete isn’t affected by this. The answer lies in the polypropylene fiber that is added to the conventional concrete mix. These fibers melt away when concrete is subjugated to extreme heat and leave a canal network behind as residue allowing the water vapors to escape, thus preventing any build-up of pressure inside. The same approach can’t be used with the self-compacting concrete because the PP fibers take away its ability to self-compact. The amount of PP fibers in self-compacting concrete is, therefore, kept low.

Scientists at the Swiss Federal Laboratories for Materials Science and Technology (EMPA) claim to have finally come up with a solution. They created a number of thin concrete walls that contained PP fibers and some of them also had a synthetic material, Super Absorbing Polymer (SAP), incorporated into the concrete mix.
Self-Compacting Concrete Is Now Fire-Resistant As Well 3

SAP is able to absorb water many times its own weight and idea employed was to have the SAP soaked in water beforehand, thus causing it to swell up (dry volume). During the setting of concrete, the water was taken out of SAP via porous cement matrix. This caused the SAP to shrink while leaving hollow spaces inside. The little amount of PP fibers along with these hollow spaces were enough to create a canal network, allowing the concrete to withstand extreme heat.Self-Compacting Concrete Is Now Fire-Resistant As Well 2

All of the concrete walls, including the ones with SAP and the ones without it, were subjected to 1,000 ° C by means of a radiant heater. After 1.5 hours, it was noted that the concrete walls containing SAP only had some minor cracking while those without it showed severe flaking and chipping. The team has already applied for a patent pertinent to this amazing new technology and is hopeful that adding fire resistance will bring about a whole new versatility to self-compacting concrete.

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