A MICROMECHANIC MODEL FOR CHARACTERIZATION OF CEMENT PASTE AT EARLY AGE VALIDATED WITH EXPERIMENTS

The gradual evolution of the material properties of a cement-based material, i.e. the stiffness of cement paste, is the result of the continuous change of the microstructure with the progress of the hydration process. Based on an existing micromechanical model for the simulation of the shear and elastic modulus of cement paste, this paper is orientated to experimentally determine the structure parameter k in this model. The dynamic elastic modulus, shear modulus, the degree of hydration and the ultrasonic pulse velocity were determined for cement pastes with water/cement ratios of 0.50 and 0.60. The structure parameter k was determined and applied to the micromechanical model, where the evolution of the modulus of elasticity is predicted and compared with experimental results.