Quality Control of the Slab's Concrete

For those of you who have paid attention to the recent press about slab issues (particularly out west of Melbourne), you may, as I have, wondered about what, if any quality control was in place for the slab and it's concrete.

Our particular slab was thicker than normal. This particular thickness that I'm talking about is the thickness of the concrete above the waffle pod. Most are 85mm or 100mm. Ours was 125mm.

In addition, the comments from both our independent inspector and the guys who put it in place also said that it was a very heavily engineered slab. More so than usual. This was in relation to the amount, and gauge of mesh put in place.

The engineers who designed the slab, it's piering etc had their reasons for doing so. Who knows! I'm not an Mech/Civil Engineer. But both my brother (Mech Eng) and my father (Mech Eng and Metalurgist) are engineers...

All of that is fine, but the engineer would also have specified the strength of the concrete itself. It is specified in MPa (Mega Pascals). What if the concrete itself was not up to specification?

I was most surprised, and utterly thrilled to see that the concrete itself being tested.

How? They take samples, let them set, and the test them. Destructively. Which is the only way that it can be tested properly.

There was a man from Boral who was taking samples of the concrete, from each truck and making testing samples.

Ever seen a thermometer in concrete? Now you have.

Samples from each truck were taken and placed into these setting pots. They each had a base and split down the middle.

They were then vibrated to allow the concrete to settle and then get rid of all air bubbles etc.

All of the samples were gathered together, and would be allowed to fully cure for seven days before being destructively tested to verify the concrete strength.

I asked the man taking the samples, how you would fix the concrete if it was not up to strength. He smiled and simply said "With a jack hammer!". Which would be the only thing you could do, as there is nothing that you can do once it's set.

So, with all of this engineering and testing, I'm hopeful that the slab issues that have plagued the building industry of late have been put to rest.

NOTE: As a follow up, please read Frame Overhang Issues for a discussion about slab issues and how they can be resolved.

Another follow up NOTE: The quality report has been received! Please read Quality Control of the Slab's Concrete - The Report for details.