Theory
The maturity method is a technique for predicting strength based on the temperature history of the concrete. The extent of the cement hydration depends on how long the concrete has cured and at what temperature. Maturity is a measure of how far the hydration has progressed.

The equation developed by Arrhenius allows for greater variation in cement types. It assumes a non-linear relationship for the determination of a maturity index and is suitable for a wide range of temperatures. The mathematics of the Arrhenius equation is more complex but it gives more accurate strength predictions over a variety of cement types. The maturity index is expressed as equivalent age in hours referred to a specific temperature, and is a function of time, temperature and the activation energy of the cement.