## 3 Results
### Results of Test on New Jersey Barrier Specimen
Figure 18 presents the time evolution of relative humidity as recorded by the different sensors (HI4, HI5, HI7, and HI8) embedded in the New Jersey-type concrete barrier specimens. Each subplot corresponds to a specific sensor, with its identifier shown in the upper left corner and its location marked in the lower right. The data reveal distinct thermal and moisture gradients depending on the sensor position. For instance, sensors located closer to the surface show more pronounced fluctuations in relative humidity, particularly during the early hours of curing, likely due to greater exposure to ambient conditions. In contrast, sensors embedded deeper within the concrete exhibit more stable readings, reflecting the insulating effect of the material. These trends support the hypothesis that sensor location significantly influences the measured environmental conditions within the concrete mass. Humidity sensors exhibited similar trends, with a significant change observed around 14 h into the test. The relative humidity initially decreased and then oscillated within a specific range until the test concluded. The average humidity value was 69.17%, with a standard deviation of \(\pm\)5.06% and a coefficient of variation of 7.3%, reflecting acceptable consistency despite varying exposure. It is important to note that all relative humidity variation curves display a sudden decrease of approximately 4% around 14 h from the start of the test, observed across all areas measured by the moisture sensors. Additionally, all curves follow a similar oscillation pattern over time. This prompted a detailed analysis of the relationship between relative humidity and the temperature inside the concrete, as well as with ambient temperature. Figure 17: Estimated thermal evolution curve based on internal temperature data from the New Jersey barrier specimen. The curve illustrates the typical heat release pattern during cement hydration, including initial and final setting phases. Figure 19 illustrates the temporal evolution of three key parameters: internal concrete temperature, ambient temperature, and relative humidity. During the first 14 h, the internal temperature of the concrete rises from approximately 33 \({}^{\circ}\)C to a peak of 35 \({}^{\circ}\)C, while the relative humidity drops from 100% to around 94%. This inverse relationship suggests that the heat generated by cement hydration accelerates moisture migration from the concrete interior to the surface. After this initial phase, the internal temperature begins to decline, and the ambient temperature--rising to approximately 27 \({}^{\circ}\)C--becomes the dominant factor influencing further humidity loss. The relative humidity continues to decrease gradually, stabilizing around 90%. These trends indicate a transition from hydration-driven thermal effects to environmental control over surface moisture. The consistency of the curves supports interpretation, even though no statistical correlation analysis was performed. In summary, during the phase where chemical reactions inside the concrete predominate, the observed trends suggest that surface humidity is influenced by the heat released from cement hydration. As this process progresses, the observed data suggest that ambient temperature becomes the predominant factor influencing surface humidity loss. Based on the internal temperature histories, the maturity index M(t) was computed to illustrate how the proposed workflow can feed a strength vs. time estimator once a plant-specific f_c-M calibration is available. In the present feasibility study, M(t) is reported  
Figure 18: Humidity variations measured by the humidity sensors embedded in the New Jersey specimen. The blue dot indicates the location of the sensors, and the arrow highlights the specific sensor to which each graph refers. as a QC indicator together with T\({}_{\rm p}\), t\({}_{\rm p}\), \(\Delta\)T (surface-core), and dRH/dt, which capture the hydration peak, thermal gradient risk, and early age evaporation tendency, respectively.