Temperature of concrete can be monitored manually by means of a special thermometer or automatically by the use of thermocouples connected to a data acquisition system.
MANUALLY: A thermometer is kept in contact with the fresh concrete element in order to attain the temperature of the concrete. In the case of measuring the temperature of concrete during the curing stage, a thermocouple node is embedded within the concrete element and extended outside that element whilst being insulated from the ambient temperature and the thermometer is used to attain the temperature of the concrete.
AUTOMATICALLY: A thermocouple is a temperature sensor formed by connecting wires of two dissimilar metals together. A temperature gradient between the ends of the wires generates a small DC voltage which is directly proportional to temperature. The sensitivity available depends on the materials used to make the thermocouple. They are ideal for applications where the probe is not recoverable such as embedded in a material like concrete or at great depths below the ground surface.
These thermocouples are embedded within the concrete prior to casting by binding them to the reinforcement bars. Installed at several locations within the same element, these thermocouples can provide an idea on the heat of hydration within the monitored element and provide information on the temperature gradients of the monitored element. The data is collected in-situ by means of a data acquisition system that logs the voltage difference within each thermocouple node.
AHAM uses Type K sensors and have the following specifications:-
| Type |
materials |
wire colors |
output |
temp range |
| Type K |
Chromel/ Alumel |
Green/white |
41μV/°C |
-200 - 1200°C |
|
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