Concrete Cube Size?

[bandraoi]

I've been carrying out some research on a new cement formulation. For various reasons the test blocks are 50mm cubes.
From some reading I've done the size of the test cubes affects the compressive strength results.

Is there a standard equation that's used? Can anyone recommend a good piece of literature that relates changes in sample size to cube strength. I've done some research but I haven't come up with anything definitive.

 

[Ron]

For proper comparison, formulation testing should be done to compare with existing data, to obviously check for improvement. In order to do that, you should use the same size cubes required of the standard you must typically meet...in the case of portland cement, ASTM C150 in the US. That requires the use of 2-inch (approx. 50mm) cubes.

To use other cubes sizes and then try to compare based on correlation studies is not comparing apples to apples.

 

[bandraoi]

Yeah, had a feeling that was the case, I want to recommend full size testing as the next step in the research, but it would be good to have an estimated range of expected results.

Doesn't matter that much.

 

[BigH]

As Ron said - cement (and grout) is tested in 50mm cubes - please ensure you use steel moulds and following the testing procedures as per C109. I know a few lads who did otherwise and lost a few hairs when I got here.

You post, though, said Concrete Cube size. This makes me wonder if you are testing "cement" - the cementitious materials or do you want to test concrete made with your cement formulation - in the latter, usually 150mm cubes are used (BS and IS standards). USA/Canada/Europe use cylinders.

You might like to get a copy of Neville's book on Properties of Concrete or Neville and Brooks' book on Concrete Technology. These might help you. If you want a book dealing with concrete cubes, M.S. Shetty's book is likely the best.