Generally a concrete mix is required to provide a specified strength.
The most common measure of concrete strength is the compressive strength, determined in either a cube test or a cylinder test.
The user can specify whether cube or cylinder strengths are to be used for the mix design.
Since the strength of a concrete specimen increases with time, the concrete age at testing is significant. It is also important to remember that the target strength of a mix will only be attained in practice, if the concrete is properly placed, well compacted and adequately cured.
The DOE Method, used by Firstmix, designs mixes that will provide a compressive strength as determined in a cube test. Generally cube tests give higher compressive strengths than cylinder tests. However Firstmix uses the relation of cube and cylinder strengths to convert between cylinder and cube strengths and either cylinder or cube strengths can be used in Firstmix.
The DOE Method assumes that the major factors, which determine the strength of a mix, are: