Evaluation of autogenous shrinkage of concrete based on mechanical properties of the cement paste matrix

The shrinkage of cement paste during hydration and the effect of aggregate restraining should be clarified to allow accurate evaluation of autogenous shrinkage of concrete. In the discussion on concrete shrinkage caused by paste shrinkage, the effect of restraint by aggregate is extremely important. Particularly, the mechanical action of coarse aggregates resisting the shrinkage of paste or mortar generates stress in the mortar and in the coarse aggregates, resulting in elastic and creep deformations. For this study, the autogenous shrinkage in cylinder specimens was measured. In addition, numerical simulations of autogenous shrinkage of a longitudinal cylinder section were conducted using the finite element method (FEM), in which each coarse aggregate particle was modeled. The test results confirmed that the autogenous aggregates. Besides, the shrinkage of concrete tends to increase as the elastic modulus of coarse aggregate decreases. Shrinkage of cement paste is restrained or even inhibited by the presence of coarse aggregate.