Fresh Concrete Curing Monitoring Using Acoustic Emission

In the present paper, acoustic emission (AE) is applied to monitor internal curing of fresh concrete. Processes taking place during the fresh state of concrete prove to be very acoustically active allowing detailed monitoring of the events. These processes include, settlement, production of hydrates, shrinkage cracking and correlate well with other measured parameters like ultrasonic pulse velocity and compressive strength. It is also characteristic that internal curing owing to the addition of superabsorbent polymers (SAPs) contributes to large numbers of AE activities, exhibiting the potential of the technique to distinguish between different sources based only on passive and non-intrusive use of sensors on the external side of the mold. The heavily damping nature of fresh concrete necessitates elaborate design of the setup and optimization of the sensors' placement. Parameters like the total AE activity, amplitude, average frequency and time domain characteristics prove very useful in characterizing the process of internal curing. The possibility to control the curing based on the results of acoustic monitoring is also discussed.