The hardening process of concrete is taking place during the very early ages of a concrete structure compared with its total service life. However, the method of curing and the treatment of the concrete structure during these first few days or weeks is very crucial for its final performance and durability. The risk of early-age plastic shrinkage cracks or thermal cracking due to temperature gradients may define the need for curing and protection of the concrete. Furthermore, the concrete skin should be protected properly against evaporation until a certain maturity or strength is obtained in order to ensure sufficient strength and durability. These criteria are often stated in the execution specifications for a project or via standards such as the EN 13670.
The Concrete Centre has been involved in the development of methods and tools to help the concrete producer to plan, to document and to predict the hardening process of a concrete structure under various ambient conditions.
The concept of maturity using the Arrhenius’ law was introduced by the DTI in the 1970s and it is still being used extensively around the globe.
The large Danish infrastructure projects in the 1990s Great Belt and Øresund Links helped to refine and further develop computer tools being used by contactors to simulate temperatures and early-age stresses within a concrete cross-section during hardening.
How can the Danish Technological Institute help you?
- Training of engineers to understand and use the principles of curing, maturity and early-age phenomena.
- Determination of early-age concrete properties based on a given concrete mix design. Strength development, heat of hydration, early-age creep and shrinkage, etc.
- Documentation of curing according to the specifications, including temperature monitoring.
- Simulation of temperatures by means of software tool 4C-Temp&Stress.
- Special assistance on hot weather or cold weather concreting. For instance the use of cooling pipes or heating wires.