determine young modulus experimentally writing and caclulate

hi, the aim of this project is to determine the young modulus in concrete specimens by the method of flexural stength test...In order to do this i choosed 3 different grades of concrete c30,c40,c60 and i cast 6 cubes 100mmx100mmx100mm and 2 beams 500mmx100mmx100mmm for each grade of concrete...i tested already the concrete cubes in 7, 14 days. i have the results from the tester in KN i made these concrete cubes in order to check if i meet the required strength 2 cubes in 7 and 2 cubes in 14 days...so about the beams im going to put these in a tensile load tester and i ll applie force in a single point in the middle of each beam...then i ll measure the depression...the formula that im going to use to find the young modulus is δ=P*L^3/48*E*I p=pressure L=length of the beam specimen E=young modulus I=bending moment (so are all known) and i need to solve this equation to E. for each grade of conrete and compare this to eurocodes 2