The Concrete Network

Concrete is tested for strength by breaking cylinders.


  1. Choose the target slump
  3. Estimate the water and air content using ACI 211.1 Table 6.3.3.
  4. Select the water-cement ratio.
  6. Estimate the coarse aggregate content.
  7. Estimate the fine aggregate content.
  8. Adjust for aggregate moisture—wet aggregate can significantly reduce the amount of water to be added.
  9. Make trial batches to see what you've got.

So you see that after all these fancy calculations, the bottom line is that concrete is still designed by experience with previous mixes or by making trial batches in the lab and testing the concrete. Nothing beats experience with a mix. Many decorative contractors will have 4 or 5 mixes that they use for different applications or weather conditions. If you have these mixes already in your ready mix provider's office, he can quickly pull out the design and you can tell him to bring your mix #3 or #5.