Using microwave near-field reflection measurements as a non-destructive test to determine water penetration depth of concrete

•Non-destructive test for concrete permeability studied.•Good correlation with standard destructive test for concrete permeability (ISO 7031).•.New approach for non-destructive estimation of structures of concrete permeability.

A non-destructive version of a standard test for concrete permeability has been demonstrated. The method is based on water penetration depth estimation from near-field microwave measurements using an open-ended rectangular waveguide. In particular, water penetration is determined from the differential measurement of reflection coefficient in the S-band before and after injection of water under pressure. Experimental results show a good correlation between the standard destructive test and the new method. Microwave measurements simplify the standard test avoiding the need of drilling out a sample from the structure and thus reducing both the cost and time needed in the analysis.