50 MPa concrete mix design Australian Standards

[MScott2989]

Hi all,

I'm having some problems getting my head around the concrete mix designs for different grade concrete. Specifically, I need to make test specimens for 50 MPa concrete according to Australian Standards. Would the ratio of C:FA:CA be specified by Australian Standards? If so, does anyone know where I can find the specific ratio?

Thank you

 

[Ron]

Aggregate ratios have more to do with durability and application than with strength. You can achieve high strength with a variety of aggregate ratios.

Trial batches will give you a reasonable strength design. For starters, use 65% coarse aggregate and 35% fine aggregate. Too much fine aggregate increases water demand, thus making the cement content higher to maintain a particular water-cement ratio. It also makes the mix more "harsh" or difficult to place.