Q.: If you are using pullout tests to determine stripping time-for-formwork, how do you know when to pull out the specimens?

A.: If done too soon you might use up all the available pullouts and not have one available when you need to prove that it is safe to strip.

This little maturity meter that resembles a thermometer should help. You cast it into the concrete and read it periodically. This meter is really a device that gives what is called a time-temperature maturity reading.

This value is a measure of how much, up to the time you read the meter, the temperature experience of that particular concrete has contributed to its strength. Then all you do is use that number, with a chart made for your particular mix, to read the approximate strength at the time. This tells you whether it is getting to be about time to make a pullout test.