Hydration evolution of C3S-EVA composites analyzed by soft X-ray microscopy

The effect of poly(ethylene-co-vinyl acetate) or EVA on the hydration of a pure C3S was investigated by transmission soft X-ray microscopy in highly diluted systems. EVA particles are readily recognizable by their spherical shape and semitransparency to soft X-rays. Polymeric particles adsorb on the surface of hydrating C3S grains, and act as nucleation agents in the development of the composite microstructure. The formation of a polymeric film was observed after a few hours of hydration. Fourier-transform infrared spectroscopy supported the conclusions that a highly soluble phase is formed as a result of EVA-hydrating C3S chemical interactions.