10 Dec 2020

Cracking Up!

Cracking Up!

At this time of year our technical support are often asked "how do I fix cracks in my new concrete??"

Well, the tongue-in-cheek answer is that "prevention is better than cure......so avoid getting them in the first place"!!

This is where a little knowledge and some K-Seal Concrete Curing Compound can save you a fortune....

Pouring concrete accurately can be a tricky job at the best of times, but high summer temperatures increase the likeliehood of shrinkage cracks, if you don't take precautions.  So whether you are a specialist contractor forming concrete in a multi-storey apartment block or a DIYer laying in a garage base, you need to understand  the issues around hydration and shrinkage.   But apart from the obvious precaution of designing in expansion joints, the danger of concrete drying out too fast and cracking is more common than most people think. 

So what causes shrinkage cracks? 

Well if we look for example at a 100mm concrete base, the top 50 mm closest to the air and sun's warmth cures faster than the bottom 50mm in contact with the cold ground, isolated from air.   Inevitably this 2 speed curing creates a tension between the top and bottom layers.  The top layer shrinks slightly as moisture leaves through evaporation but it is bonded to the slower curing bottom layer which hasn't shrunk.  The inevitable result is a tear or crack.

However, by simply applying Concrete Curing Compound soon after the concrete is poured you can alleviate this problem by slowing (retarding) the moisture evaporation rate.  Slowing the water loss, regularises the curing and improves hydration of the concrete which in turn makes it stronger.  Kingfisher K-Seal Curing Compound is easy to apply by low pressure spray or roller, reduces shrinkage cracks, makes for a stronger mix and creates a usable dust-free surface.