7-day Flexural Strength to Determine 7-day Tensile Strength

[CWEngineer]

I using UFC 3-260-02 Pavement Design For Airfields, 30 June 2001 to Calculate the percentage of reinforcing steel required in the longitudinal direction.

One of the parameters is f(subt) = 7-day tensile strength of the concrete in psi determined using the splitting tensile test. This reference has a Figure 5-1 to convert the 7-day flexural strenght into tensile strenght.

Can you guys give me advice or point me to a reference in calculating the 7-day flexural strength for 3,000 psi, 4,000 and 5,000 psi so that I can find the 7-day tensile strength form this Figuere.

Thanks

 

[civilperson]

Beams are made of the paving mix and stored for three point loading results. The compressive strength has an assumed correlation to flexural strength, ACI 318 9.5.2.3, fr = 7.5 x SQ Root (F'c).

 

[CWEngineer]

Is the Modulus of Rupture fr the same thing as flexure strength?

Do you know how would I determine the 7-day flexural strength?

THANKS