Concrete/mortar water phase transition studied by single-point MRI methods

A series of magnetic resonance imaging (MRI) water density and T∗2 profiles in hardened concrete and mortar samples has been obtained during freezing conditions (−50°C < T < 11°C). The single-point ramped imaging with T1 enhancement (SPRITE) sequence is optimal for this study given the characteristic short relaxation times of water in this porous media (T∗2 < 200 μs and T1 < 3.6 ms). The frozen and evaporable water distribution was quantified through a position based study of the profile magnitude. Submillimetric resolution of proton-density and T∗2-relaxation parameters as a function of temperature has been achieved.