PRELIMINARY RESULTS ABOUT 3D DISTRIBUTION OF SUPERABSORBENT POLYMERS IN MORTARS

摘要

Water entrainment by means of superabsorbent polymer (SAP) is a recent techniquedeveloped for avoiding early-age cracking of high-performance concrete. The dry SAPparticles, upon contact with the mixing water, absorb pore fluid and swell, becoming 2 to 3times larger. The SAP form stable water-filled maeropore inclusions in the fresh concrete,which keep the internal relative humidity of the concrete high and prevent self-desiccationshrinkage during hardening. Addition of SAP has also proved useful for increasing freeze-thaw resistance of concrete by acting in a similar way as air entrainment. In view of theefficiency of both internal curing and frost protection, it is essential to know the dimension ofthe SAP in the swollen state and their spatial distribution in the concrete. In this paper, X-ray microtomography is employed to study the particle size distribution ofSAP and their three-dimensional distribution in high-performance mortars. Theseexperimental results may be used to verify models about the behaviour of the SAP inconcrete.