TMA PT 1600 (TMA L72)

Different thermal expansion behavior of bricks depending on the relative humidity

Humidity can have a huge influence on many materials, especially materials that are used for packaging or construction such as polymers, wood, bricks, concrete and many more.In the given application, two historical brick variants have been investigated and compared to contemporary, similar bricks regarding their expansion at different humidity levels.Therefore, the materials were first measured at linear expansion mode using a Linseis TMA PT 1600 (TMA L72).The result was a straight forward linear expansion.Then the same experiment was repeated using a water vapor generator to simulate 35% relative humidity.The samples were kept at these conditions for 2 h and then the expansion coefficient was again determined vs temperature keeping the humidity level constant.The result shows a significant increase in linear expansion behavior due to swelling of the material.This effect will occur at any humidity level and should be considered carefully when calculating the expansion of such materials for any application.