Skip to main content

Component-temperature-controlled hardening test CTH (climatic box)

Testing of real strength development in concrete structures using cubes stored in a component-temperature-controlled water bath.


In the initial test the strength development of a concrete type is determined in the laboratory at approx. 20°C.

Concrete testing during construction:

  • Identity tests on on-site produced cubes under laboratory conditions at approx. 20°C (ÜK2/ÜK3); verification whether the concrete delivered to the construction site corresponds to the initial test.
  • If necessary, hardening tests on cubes to monitor the actual component strength.

Strength development in the components on-site is temperature dependent:

  • For non-massive components, the temperature/strength development in the cube stored next to the component is approximately the same as in the component.
  • In the case of massive components, the concrete heats up much more in the component than in a cube stored next to the component; temperature gradients form between the surface and the core. The strength development in the component is usually accelerated. The assessment of which strength is present at which point in the component becomes more demanding.
  • By means of a CTH, the strength development at any point in the component can be simulated and tested.


Application cases for the CTH

  • Determination of the point in time when prestressing can be applied,
  • Determination of the time of stripping,
  • Determination of the point in time when support measures can be removed, etc.



  • Installation of the temperature sensors in the building component, location according to the instructions of the construction site.
  • Installation of the CTH.
  • Start of the CTH on the day of concreting, instruction of the construction site regarding the loading of the box with the cubes.
  • Temperature recording of component, air and water bath over time during the measure.
  • Removal of cubes on instruction of the construction site for immediate compressive strength testing.
  • Deinstallation of the CTH and transmission of the temperature records as an Excel file after completion of the measure.
Sensor on-site
Display of the measured values