How to determine the temprature of mass concrete after pouring?

Question

How to determine the temprature of mass concrete after pouring?

Answer 1

If you are looking for a fairly close estimate, you can always use the exponential decay formula.

N(t) = N e^-lambda*t

where N(t) is the temperature at some time t, N is the initial temp at time 0, lambda is the cooling factor, and t is the time.

What you do:

Take the temperature of the concrete right after you pour. Then measure some time t and take the temperature of the concrete again...N(t). (Make sure t is low enough that the concrete does not cure) You can plug these values into the equation and solve the cooling factor.

Solving the cooling factor:

lambda = -ln(Nt/N)/t

lambda is constant for any time t therefore plug it in the original equation:

N(t) = N e^-lambda*t

You know N, lambda

pick any time t and you can solve for N(t)

This is a good way to calculate the temp of the concrete after it cures.

Hope this helps

Answer 2

It depends on so many factors:

1. thermal conductivity of the ground,

2. thermal conductivity of the forms,

3. temperature and heat capacity of the ground,

4. temperature of the air,

5. wind,

6. humidity,

7. and others,

that there is no simple formula for calculating it.

Also.. the temperature will not be uniform throughout the pour.

A thermal (infared) temperature gauge is about the only way I know to see the surface temperature.  If you really must know the internal temperature at points inside the slab, then you must embed (permanently) some temperature gauges and route the wires out (the bottom of the slab, etc).   There are cheap temperature gauges available.