## 3 Results  
The results consisted of the resistivity measurements using PCB sensors. The resistivity profiles over depth for the transmission and Wenner configurations at different temperatures and degrees of saturation were studied to show the effect of the temperature on the calibration curves correlating the resistivity to the degree of saturation. First, a study of repeatability and reproducibility of the resistivity measurements using the PCB sensors was carried out for specimens S1 to S5 in saturated conditions and at temperature T = 20 \(\pm\) 2 \({}^{\circ}\)C. The coefficient of variation for repeatability ranged between 0.06% and 1.86% for resistivity measurements repeated three times. As for the reproducibility, which is associated with variability due to the sensor and concrete material among the five cylindrical specimens, the coefficient of variation of resistivity was equal to 4.6% for specimens S1, S3, S4, and S5 in the transmission configuration and 5.3% for the same four specimens in the Wenner configuration. This variation became higher when including specimen S2, where it reached 11.1% and 8.9% in the transmission and Wenner configurations, respectively. This might be explained by a difference in the material of specimen S2, possibly due to concrete casting or vibration. Figure 3 shows the resistivity profiles over depth using the transmission and Wenner configurations in nearly saturated conditions (\(S_{r}\) = 95.0 \(\pm\) 2.0%) for all the specimens. Comparable values between the two measurement configurations are noted with 1.7% of variation, on average. Figure 2: View of a PCB sensor placed on the axis of a cylindrical mold designed to cast the concrete specimen. Second, a study of the variation of the resistivity profiles was carried out for all the specimens at different degrees of saturation (\(S_{r}\) = 72.2 \(\pm\) 1.0%, 53.3 \(\pm\) 0.3%, and 33.8 \(\pm\) 0.5%) for both the transmission and Wenner configurations. Figure 4 shows resistivity profiles over depth in the S1 specimen for the transmission and Wenner configurations at different temperatures T = 20, 45, and 60 \({}^{\circ}\)C, and at different degrees of saturation. For all configurations and at each temperature, the resistivity obtained is higher at lower saturation degrees, which agrees with the results reported in the literature [39, 40, 41]. For a relatively dry concrete (\(S_{r}\) = 33.8 \(\pm\) 0.5%), we obtained average resistivity values ranging between 1700 and 1900 \(\Omega\).m at T = 20 \({}^{\circ}\)C for the transmission and Wenner configurations. The maximum (3200 \(\Omega\).m) and minimum (870 \(\Omega\).m) resistivity values obtained here comply with the values reported in the literature for a dry concrete with CEM I cement between 1000 and 3000 \(\Omega\).m [21]. We note in Figure 4 that the specimen is less homogeneous at \(S_{r}\) = 33.8%, and that a larger variation in resistivity (high standard deviation) is observed over depth. This variation can be explained by the waiting time which was too short for the specimen (\(\O\)11 \(\times\) 22 cm) to be homogenized; an increase in the homogenization time, by doubling it, for example, might decrease the variation along the depth. Moreover, as degree of saturation decreased, resistivity values increased and measurements became more difficult to take because of increasing contact resistances between electrodes and concrete, thus generating greater variability in measurements. Furthermore, the connectivity of the liquid phase was no longer ensured at low degrees of saturation, which limited the flow of electrical current. For each type of configuration at a fixed temperature and degree of saturation, the average resistivity over depth was calculated for each specimen. Then, to establish the calibration curves between resistivity and degree of saturation at each temperature, the average resistivity among all specimens was calculated for both configurations and for a fixed temperature and degree of saturation.