In accordance to those observations, the values of spread on table
strongly reduced (Figs. 9 and 10). The ionic nature and interconnected
chain structure of SAP particles increase the chemical affinity
towards the water molecules, enlarging the absorption level
[31]. As a consequence, the relative amount of free water available
in the mixture diminishes. Then, W/B needs to be adjusted
(increased) to preserve the workability of mixtures for an extent
period. In fact, sometimes the presence of SAP particles turned
the samples too stiff to be tested in the available rheometer, this
effect being attenuated by using additional water dosage as seen
in mortars with W/B = 0.72 (Figs. 5–7).