Quantitative characterisation of absorption capacity and dosage of SAP in cement paste

The internal curing effect of superabsorbent polymers (SAPs) on high- and ultra-high-performance concrete has been widely acknowledged. For a certain amount of entrained water needed for internal curing, an accurate assessment of the absorption capacity of SAP in cement paste is necessary rather than other solutions to properly proportion the dosage of SAP in cement-based materials, thus attaining their effectiveness in mitigating autogenous shrinkage with fewer adverse effects. In this paper, early-age performances of cement paste with and without SAP, including rate of heat evolution, capillary pressure and rheological properties, are compared, with simultaneous observation of the particle size of SAP in the cement paste. Results indicate that the absorption capacity of SAP in situ can be quantitatively evaluated through the comparison of the rate of heat evolution and capillary pressure from the addition of water to setting. The ideal dosage can be confirmed based on the theoretical amount of entrained...