Development and validation of a dimensional variation measurement set—application to the plaster setting

A method is developed and applied to investigate the shrinkage–swelling phenomenon during the setting of plaster. It is based on an optical position-sensing device which allows for a continuous measurement of the distance to a target without contact, by means of a triangulation technique. The method is validated for two types of moulding plaster and for a building plaster blended by using different amounts of a controlled grain-size dihydrate gypsum.