Monitoring the size evolution of capillary pores in cement paste during the early hydration via diffusion in internal gradients

The internal gradients arise inside porous media due to the susceptibility contrast between the porous matrix and the confined liquid. They produce in the presence of diffusion phenomena an extra attenuation of the echo train signal in the Carr–Purcell–Meiboom–Gill (CPMG) experiment. In the present work we exploit this extra attenuation of the echo train to determine the pore size evolution of capillary pores in cement paste during the early age hydration. Thus, both the effects of the temperature and of a superplasticizer on the pore size evolution are investigated. It is observed a slight reduction in the size of capillary pores of cement paste by decreasing the temperature. However, no reduction of the pore size could be detected as result of introducing a superplasticizer and this can be due to the preparation approach of the sample.