Home
> Uncategorized > Concrete Testing – Site Practice?
Concrete Testing – Site Practice?
Does concrete on site get sampled for testing in cylinders, 6″/150mm cubes or smaller 4″/100mm cubes? I ask because, although I know what the BS says, I was recently told that site practice has moved towards using smaller 100mm cubes rather than the standard 150mm. No evidence was offered to support this but I don’t wish to tell someone that they are misinformed without some evidence to support my position. What do you know of your site or others you have visited?
Categories: Uncategorized
Holdfast Training Services Trial Blog 
Hi Richard,
One of our contractors was using 150mm cubes for concrete and 100mm cubes for grout. The other was using 100mm cubes for both.
When I queried the use of 100mm cubes for concrete with the quality manager we found a Concrete Society guidance note (OS 010 – “Making Cubes”) which states that 100mm cubes are acceptable for concrete with aggregate size of 20mm or smaller:
“Either 150mm or 100mm cube moulds are acceptable for the strength test, but if the
aggregate in the concrete is greater than 20mm, 150mm cubes are generally necessary.
For safe manual handling, 100mm cubes are preferable.”
This note is taken from BS 12350 and BS 12390 and is Concrete Society so seemed legitimate and we haven’t stopped anyone using 100mm cubes. The guidance note is on IHS.
Hope this helps.
Tom
Thanks Tom,
As I say, very happy with what it says in the BS, question was what is typical site practice. My experience suggested 150mm but I think you are suggesting a 50:50 split with a potential for move towards 100 becoming more common (sensible).
Richard.
We are using the 100mm ones on site. This complies with BS 12390 and is apparently standard practice for our UKAS accredited testing lab.
Another reason is purely logistical, we are pouring 100s of m3 per day, with a requirement for 4 cubes per 25m3, this reduces the size of the storage tanks need. Small difference in size but it mounts up!
Thanks John,
As per my response to Toms comment. I am clearly becoming as obsolete as a 150mm cube mould: only needed if for the bigger stuff and used less frequently than in the past!
I spoke to the materials technician on our site and he said they avoid 150mm cubes partly for manual handling reasons as they weigh around 25kg when made up. Subscribing to the Concrete Society guidance note he also said that in his experience concrete with aggregate greater than 20mm is rarely used nowadays.
Thanks Colin,
Quite agree that smaller makes sense for most structures because it is indeed rare to use aggregate above 20mm. 40mm aggregate is the common size for concrete used in road base construction so anyone involved with highways would probably use a 150mm cube. A standard 150mm cube comes in at a little under 10 kg but add on the mould and it rises so a 100mm cube at 2.5kg makes more sense if you’re working in structures with 20mm and 10mm aggregate. Perhaps time we moved over to smaller cubes at Wainscott.
Richard.