a = 0.812278/(tl t2)
Where:
a = thermal diffusivity, ft2/ h r
And,
(tl t2) = elapsed time between
minutes, and
0.812278
Equation 3.1
Temperature differences of 80 F and 20 F in
numerical factor applicable to 6- by 12-in cylinder.
0 5 10 5 20 25 31
TIME IN MINUTES
Figure 3-11 Example Showing Calculation Of Thermal Diffusivity Of A Concrete
Cylinder
Compressive Strength
The compressive strengths of the samples were determined at ages of 14 and 28
days. The compressive strengths were determined according to ASTM C39-93a,