Calorimetry measures the heat generated from the early hydration reactions of cementitious materials. The heat outflow tracks the hydration reactions of cement, which gives visibility into the behavior of concrete or mortar in a way that a simple set time or compressive strength test could not.

The timing and shape of the temperature curve obtained through calorimetry is an indicator of relative performance of cementitious mixes, and of potential adverse interactions among materials used in the mix.

In Adiabatic calorimetry, concrete samples are in a perfectly insulated environment, simulating hydration at the core of a mass concrete application.

In an isothermal calorimeter, the outside temperature is maintained constant to simulate different curing temperatures. The temperature control further allows for excellent repeatability

Typical uses of calorimetry can be described as follows:

Mix Design Optimization

Compare mixes using different sources of cement
Compare different brands or types of admixtures
Compare mixes with various Fly Ash or Slag sources. Look for compatibility.
Test the effect of different admixture addition times (upfront in mixing water or delayed)

Troubleshooting and Performance Limits

Determine the maximum dose of an admixture with a given cement before performance gets affected. Especially recommended for high performance concrete.
Help determine the optimum dosage of admixtures or SCMs with different cements
Spot potential problems of adverse material interaction

Performance Prediction

Maturity testing to infer compressive strength
Failure modes based on statistical analysis / mix tracking
Activation Energy and Crack prediction
Thermal indicators to infer setting time

Example of a calorimetry curve

A: Early C3A hydration
B: Thermal Indicators of Early and Late Set
C: Second Peak of Hydration / Sulfate Balance
D: Maturity / Relative Strength Gain