Modeling water absorption in cement-based composites with SAP additions

Abstract

The ability of Superabsorbent Polymers (SAP) to block water flow along cracks in cement-based materials has become an attractive feature of these admixtures. The diminution of fl w rates in such composites are attributed to the capacity of the SAPs to absorb water and swell in the crack, but no evidence exists in literature that indicates one or the other cause. On the other hand, the SAPs present in the bulk matrix might act as distributed sinks through which water is absorbed (water that otherwise would have continued its path into the matrix). In this paper a preliminary effort is made to numerically model the effect of SAPs on the water absorption by mortar. A lattice-type model is proposed to predict both the bulk water absorption and the resulting penetration depth of water into the cementitious matrix. The results of the simulations point out the mechanisms of water absorption in mortar containing SAPs.