Spectral induced polarisation (SIP)

The originally geophysical method "Spectral Induced Polarization (SIP)" is an enhancement of the conventional resistivity measurement of soils and building materials. The substantial improvement of SIP is the consideration of the frequency dependency of the complex electric resistivity. Depending on pore space and fluid related properties specific behaviour is observed in the frequency range of 1 mHz to 10 kHz. SIP provides new perspectives for the non-destructive testing in the building industry and cultural heritage. Recent research focusses mainly on the value of SIP for general material characterization, moisture investigation and non-destructive damage assessment.

A working group has been established at the Deutsche Geophysikalische Gesellschaft (DGG - German Geophysical Society). The web link is http://www.dgg-online.de/aks/ip.en.php. In the context of this working group research activity is currently running at BAM concerning reference materials and electronic test networks.

Main research currently targets on:

1. Investigation of structure, material and moisture content on dams and dikes (EU project TAILSAFE, BMBF project DEISTRUKT, see also poster).

2. Investigation of the low frequency electrical properties of masonry. Characterization of salt- and water associated damages. Fundamental research to automated tomographic measurements.

3. Non-destructive condition analysis of wood. Investigation of sane and affected, live and dead woods. Estimation of anisotropy effects (Nondestructive Technologies for Tree Testing).

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