No tags yet.
A correlation can be made between cast compression samples (cubes or cylinders) and cored samples, which will be the first thing you will have to establish. Correlation of flexural and compressive test results can also be determined, but it is only an approximation.
Just as background, concrete is usually assumed to be about 10% as strong in tension as it is in compression. That tensile strength is the basis for its ability to resist bending, or its flexural strength.
ACI 207R, Effect of Restraint, Volume Change, and Reinforcement on Cracking of Mass Concrete, states in Chapter 3 that concrete’s tensile strength is often taken as 6.7 times the square root of its compressive strength. It also notes that where a conservative estimate is in order, you can use a minimum tensile strength of 4 times the square root of the compressive strength.