Autogenous shrinkage is a problem in cementitious materials with a low water-to-binder ratio.
When the internal relative humidity decreases due to the ongoing hydration reaction and selfdesiccation,
autogenous shrinkage takes place if no external or internal water source is present. This
may lead to cracking and eventually cause durability problems in constructions. Ideally, the internal
relative humidity should be maintained during hydration of the cement paste. Superabsorbent
polymers (SAPs) may be used to mitigate autogenous shrinkage. When self-desiccation occurs,
these polymers will release their absorbed additional mixing water due to increasing capillary forces
to stimulate internal curing. This release of water towards the cementitious matrix and the effect on
the cementitious matrix itself can be studied by means of neutron radiography. In this study, thin
samples of cement paste were casted between glass plates and the evolution of the internal water
amount was studied as a function of time. In specimens without SAPs and a water-to-binder ratio of
0.30, shrinkage was seen. Furthermore, autogenous shrinkage was reduced in cement pastes when
using SAPs and an additional entrained water-to-binder ratio of 0.054. The release of water from
smaller SAPs (100 μm dry size) seemed to be more promising compared to bigger SAPs (500 μm)
with the same absorption properties. The technique of neutron radiography supports the findings of
shrinkage tests where SAPs were already proven to be useful. This opens additional insights
towards the application of SAPs in the construction area
