Spectral induced polarization of low-pH cement and concrete

Concrete is the most used material for civil and industrial infrastructures. In the context of a geological disposal of nuclear waste, concrete performance may be degraded when in contact with the host formation. The ability to monitor the changes of the concrete properties using the spectral induced polarization (SIP) method is therefore of great interest. In our study, SIP laboratory measurements in the 100 mHz to 45 kHz frequency range were carried out on low-pH cement and concrete. These materials exhibited a very high resistivity (mostly above 10 k Omega m) and a high phase shift (mostly above 100 mrad) between measured voltage and injected current. The complex resistivity measurements were interpreted using electrochemical and microstructural membrane and Maxwell-Wagner polarization models. Relevant information on the mean pore size, pore size distribution, and connected porosity was obtained from SIP, opening up the possibility of using our approach to monitor concrete stability in-situ.