Development of a new experimental technique for the study of the autogenous shrinkage of cement paste

After defining and describing the main physicochemical mechanisms governing the autogenous shrinkage of concrete, a number of different experimental a pproaches used to asses this phenomenon are discussed. The base principle a nd a detail description of a new experimental technique aiming to completel y characterise the autogenous shrinkage of a cement paste are presented. Th e originality of the technique comes from the fact that the variation of th e external volume (external autogenous shrinkage) and the volume of the gas -filled spaces in the liquid phase after the hardening (internal autogenous shrinkage) are measured separately and simultaneously. The total autogenou s shrinkage is the sum of the internal and external autogenous shrink-ages. A number of experimental results are presented to demonstrate the validity of the proposed experimental approach and to analyse the effect of water/c ement ratio on the development of internal and external shrinkages.