The influence of superabsorbent polymer on the properties of alkali-activated slag pastes

This paper discusses the interaction between superabsorbent polymer (SAP) and alkali-activated slag pastes and the influence of SAP on the properties of the pastes. SAP showed higher absorption in pore solutions extracted from alkali-activated slag pastes compared to that extracted from portland cement paste. Hydrogel desorption in alkali-activated slag matrix activated with Na2CO3 was noticeably delayed compared to alkali-activated slag matrix activated with NaOH matrix or portland cement matrix; this is attributed to a significant delay in the solid skeleton development in this matrix. Addition of SAP was shown to be effective in reducing autogenous shrinkage in alkali-activated slag pastes. A general reduction in compressive strength and electrical resistivity was observed in alkali-activated slag pastes when SAP was added; macrovoid formation and increased overall water/binder are possible reasons for this reduction, respectively.