Thin-Layer Shrinkage System

The Schleibinger Thin-Layer Shrinkage Laser Measurement System is designed for measuring the shrinkage of thin layers of compounds.Some building materials like self-levelling flooring compounds or plasters are applied in thin layers. These fast setting mortars set and harden within a couple of hours and subsequent drying of such a thin layer is generally terminated after the first day. In order to investigate the dynamics of early shrinkage and expansion a special set-up consisting of two laser units horizontally aligned are employed. This set-up allows investigation of the different formulation parameters and their influences on the different stages of shrinkage and expansion, namely the plastic shrinkage, setting expansion and drying shrinkage. The shrinkage/expansion behaviour is strongly related to both, external (climate) and internal (formulation) factors. With respect to the latter, begin, intensity and duration of setting are key to the overall shrinkage/expansion behaviour.

With building materials applied in thin layers shrinkages one of the major issues because of two reasons:
• The high surface-volume ratio causes evaporation to be a dominant mechanism for strong and fast physical shrinkage, and
• the intense hydration reactions can cause a pronounced chemical shrinkage, or in case of ettringite formation a strong expansion.

resolution

Laser-spot diameter