Cure-state monitoring of concrete and mortar specimens using Smart Aggregates

This paper experimentally studies the measurement of stress wave transmission properties in early-age concrete and mortar slab specimens. The studies are enabled by embedded piezoelectric-based transducers called “Smart Aggregates (SAs)” that generated and received a swept sine stress wave in the specimens at frequency range of 100 Hz - 150 kHz. Dependencies of the resonant peak amplitude and frequency of power spectrum density as transmission energy indicator on water-to-cement (w/c) ratio and effect of coarse aggregates in the specimens are demonstrated. It is shown that the changes of the resonant resonance peak have different rates for the concrete and mortar specimens with different w/c ratios when the hydration process proceeded. The potential of SA-based cure-state monitoring method for very early-age concrete assessment is discussed.