ABSTRACT
The concrete mix-proportioning methods, be it any of the methods discussed before, is always a work in progress even after the concrete trials are done and tested, because the required workability is not easily achieved nor is the desired target strength. Either the achieved strength is less than the target strength, meaning it does not meet the strength criteria or is higher than the required strength; this also means it is costlier than the concrete that would have met the required strength criteria. In addition to these intricacies, the strength tested has a high error built into it, either the strength is much less, higher, equal than what was tested, but it is unknown! In such cases, the British Ready-mixed Concrete Association (BRMCA) method of proportioning clears up all the chaos. This method is an extension of any mix design and requires the concrete technologist to test the output for at least four different proportions and then interpolate the proportion to meet the required property in fresh or hardened state; it provides a proportion for more than one grade of concrete, in addition.
After conducting trial for a target strength of 38 MPa, you end up getting 29 MPa instead after 28 days. How will you decide the proportion?
