<p>This study investigates the potential use of the non-destructive Wenner resistivity method and the chloride conductivity method in quality assessment, and in estimating input parameters for service life modelling, of concrete. The experimental investigation was conducted on plain Portland cement, fly ash and slag concretes with a range of cement replacement levels and w/b ratios. The results of this study showed that the use of Wenner resistivity to assess the ionic transport resistance without regard to the pore solution chemistry can lead to misinterpretations. This effect was especially noticeable in fly ash concretes. Similarly, penetrability evaluation by the Wenner method in air-dried specimens requires considerations of saturation effects even after prolonged wetting. The chloride conductivity test showed more reliability against the effects of the pore solution chemistry and degree of saturation. This study also highlights the importance of considering the long-term evolution of concrete penetrability in relation to the environmental conditions. In this regard, the Wenner method was very useful in the characterisation of the time-dependence of the resistance to chloride transport of concrete under saturated conditions. A promising application of this finding is in service life modelling for reinforced concrete structures under marine conditions.</p>