The effect of superabsorbent polymers on the mitigation of plastic shrinkage cracking of conventional concrete, results of an inter-laboratory test by RILEM TC 260-RSC

This article presents the results of an inter-laboratory study performed by six international research groups in the framework of RILEM Technical Committee 260 RSC “Recommendations for use of superabsorbent polymers in concrete construction”. Two commercially available superabsorbent polymer (SAP) samples with different chemical compositions were tested in terms of their ability to mitigate plastic shrinkage cracking of concrete. The SAP mixtures showed a clear reduction of plastic shrinkage cracking in conventional concrete. On the contrary, if only additional water is added and no SAP, the area of plastic shrinkage cracks increases. This suggest the ability of SAP to mitigate plastic shrinkage cracking. Upon addition of the predetermined amount of SAP and additional water, the compressive strength decreased on average by 3% for the mixtures with 0.15% SAP (by mass of cement) and by 10% for the mixtures with 0.30% SAP.