Influential factors in volume change measurements for cementitious materials at early ages and in isothermal conditions

Early age deformations, when restrained, lead to an increase of cracking risk of the material, especially in the case of high strength materials to which we apply modern high energy mixing techniques which accelerate initial hydration rate. The experimental campaign aims to investigate and understand the differences not yet explained between several autogenous measurement techniques, such as the initial swelling measured by the linear devices that is not observed in the case of volumetric measurements. The differences between the results obtained by means of devices when values are zeroed at setting time can be imputed to the intrinsic behaviour of the material within the well-defined boundary conditions imposed by the molds, and not only to the measurement artefact.