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An application is developed with surface mounted Lead Zirconate Titanate (PZT) patches 9 for sensing damage in the form of a stress-induced crack in a concrete substrate. A localized 10 crack is introduced in a controlled manner using a fracture test. Full-field displacements 11 obtained using digital image correlation are used for crack penetration and crack width 12 measurements. Electrical impedance (EI) measurements are obtained from the individual PZT 13 patches, which are attached at different locations relative to the crack. Stress wave transmission 14 measurements are performed using the PZT patches as actuator-receiver (AR) pairs. The EI 15 measurements indicate that small, quantifiable changes in the mechanical impedance of the 16 substrate are experienced by the PZT patch in the vicinity of the localized crack, which 17 sensitively detect crack initiation. The stress wave-based measurements are very sensitive to 18 the presence of physical discontinuity created by a localized crack in the stress wave path. A 19 measure of stress wave attenuation, the attenuation factor is developed, to quantify the 20 measured changes in the stress wave produced by the physical discontinuity in concrete upon