Activation Energy for the Concrete Maturity Model – Part 1: Compressive Strength Tests at Different Curing Temperatures

Abstract

Abstract The article addresses the modelling of the maturity of concrete. The apparent activation energy is the backbone of the Arrhenius model, which is typically used to model the maturity of concrete. The maturity (or the equivalent age) is influenced by the curing temperature and it is applied when modelling the hydration process and the hardening of concrete for instance in order to forecast the early-age strength to determine the time for removal of formwork or the time for prestressing. Part 1 of the article describes the background for the maturity model and the test series carried out at the DTI concrete lab. Laboratory tests at different curing temperatures (from 5°C to 60°C) are presented and the compressive strength results are modelled according to the original Freiesleben Hansen and Pedersen maturity model that has been applied in the field for many years. The tests include five different concretes, using three different cement types and the addition of fly ash. There are significant differences especially when considering the later-age strength modelling at either low temperatures or at high temperature curing.