Real-time monitoring of structural build-up is critical for robust 3D concrete printing (3DCP). We evaluate electromechanical impedance (EMI) sensing with embedded piezoelectric (PZT) sensors to track early-age structuration of cementitious binders, a key phenomenon for 3DCP. Cement pastes (CEM I 42.5 R) spanning water-to-cement ratios w/c = 0.32, 0.36, 0.40 and a phosphate-retarded paste were cast with embedded sensors. Electrical impedance (EI) measurements were recorded from casting to 4 h for the w/c series (0–7 h for the retarded mix) and were normalized to each sensor’s in-air baseline. The fundamental resonance was very sensitive to the surrounding medium: immediately after embedding, the conductance peak decreased and the resonance shifted to lower frequency, followed by continued attenuation during the nominal dormant period. Over the hydration window studied, peak-conductance amplitude was more sensitive to microstructural changes than resonance-frequency shift, and this amplitude-based metric correlated with reference measurements: small-amplitude oscillatory shear (SAOS) rheometry and Vicat penetration. The rate of change in peak-conductance amplitude ranked with composition (WC32 > WC36 > WC40). The retarded mix showed an unusual early build-up signature that preceded the hydration-driven percolation knee seen in rheology, which was reflected in the conductance trends. The mapping between shear modulus and conductance-derived features was nonlinear. EI spectrum responded from the time of casting, providing the earliest actionable indicator for process control. Overall, this preliminary study with standard cement pastes indicates that the EMI sensing offers a sensitive, embedded, and physically interpretable route to in-situ monitoring of fresh-state evolution, with potential to define practical setpoints (for example, interlayer wait times), while Vicat and rheology serve as benchmarks and calibration companions.