Monitoring steady state moisture distribution during wick action in mortar by magnetic resonance imaging (MRI)

摘要

1D Centric Scan SPRITE magnetic resonance imaging measurements were undertaken to observe the water content distribution in 10 cm length mortar specimens with a steady state water content due to wicking and evaporation. Results show bi-exponential behavior of the magnetic resonance signal lifetime T-2* in all samples, indicating at least two different water populations. The short T-2 lifetime, related to interlayer water, and its associated amplitude are constant along the sample. The long T-2 lifetime, related to water in the pore space, and its associated amplitude, change with local moisture content. In the steady state the wet front was displaced deeper into the sample as the water to cement ratio increased. The transport parameters controlling the wicking and drying were extracted by fitting the experimental profiles to two literature models. In both cases the transport parameter values increase as the water to cement ratio increases.