ACOUSTIC SIGNATURES OF DIFFERENT MECHANISMS IN FRESH CONCRETE

Early-age age concrete is characterized by complex processes that take place simultaneously, resulting in settlement, hydration, and shrinkage cracking, which in turn, define its long-term performance. In this study, fresh concrete is monitored using Acoustic Emission (AE), a high sensitivity technique that records elastic waves released by irreversible processes within the material. Monitoring the behavior of fresh concrete is essential when novel admixtures for internal curing such as SuperAbsorbent Polymers (SAPs) are added to the mix. SAPs are polymers that swell by absorbing water, which they will release back to the cementitious matrix when the free water is consumed. The purpose of this paper is to distinguish and characterize
the different processes taking place in normal fresh concrete and fresh concrete containing SAPs, based on the obtained AE parameters. The AE signatures of the various mechanisms can lead to an early-age assessment of concrete and subsequently can be connected to the final mechanical properties.