LAUSR

Abstract The distress caused by alkali-silica reaction (ASR) to concrete structures can occur long time after the reaction has been triggered. We propose to use spectral induced polarization (SIP) as a non-destructive method for early detection of ASR reaction before the damage is apparent. Our research deals with monitoring the difference between the electrical behaviour (phase lag, bulk resistivity, relaxation time, total chargeability) of non-reactive (NR) and reactive (RC) concrete samples affected by ASR. Laboratory measurements of complex resistivity were done in the frequency range 1.43 mHz-20 kHz. A Debye decomposition (DD) model was used to determine the DC bulk resistivity ( ρ 0 ), and the distribution of the chargeability as a function of the relaxation time. The total chargeability ( Σ m ) and the mean relaxation time ( τ mean ) were computed as DD parameters to characterize the ASR development. While ρ 0 was strongly dependent on the electrical conductivity of the solution (water, NaOH) with a constant change with time, both concrete mixtures saturated with the same solution showed an increase ρ 0 due to the development of the matrix skeleton over time. In this work, ρ 0 did not play a significant role to characterize the ASR development. For the samples affected by ASR, a significant evolution of Σ m and τ mean was found compared to the non-affected mixtures (RC, NRC-H2O), specially over the low frequency range [1.48 mHz τ > 10 2  s that could be associated with the polarization of aggregates affected by ASR.