A dilatometer for measuring the volume changes of concrete under load

A new apparatus is described which enables the change in volume of cement paste or concrete specimens under load to be monitored continuously. It relies upon the displacement of water from one bellows containing the specimen under load into another, unrestrained bellows. The difference between the magnitudes of the movements of the bellows is proportional to the volumetric strain. The results are shown to be in good general agreement with other volumetric strain measurements. The apparatus has some advantages over current methods.