Visualising water vapour condensation in cracked concrete with dynamic neutron radiography

[Display omitted] •Vapor penetration in cracked concrete probed with fast neutron radiography.•Full-field analysis revealed moisture clogging and discontinuous moisture fronts.•Moisture accumulation was found to precede sudden jumps in moisture profiles.•Pressure driven moisture speed is 4 times the speed of capillary absorption. This paper presents, for the first time, full-field dynamic measurements of vapour injection and condensation within a fractured concrete, observed in-operando by means of rapid neutron radiography (acquisition rate of 30 Hz with 87 μm pixel size). Time-dependant moisture evolution is analysed in terms of equivalent water thickness measurements. We observe that movement of condensed moisture along and transversely to the crack plane is non-monotonic in both space and time, exhibiting occasional sub-second jumps.