Influence of superabsorbent polymers on properties of fiber reinforced mortars containing fly ashes

High susceptibility to early cracking induced by self-desiccation processes is a major problem in concrete slabs and bridge decks segments, which are often subjected to a rapid evaporation of water. Internal curing provided by superabsorbent polymers (SAPs) can address the problem by facilitating hydration process and controlling water supply in both fresh and hardened states. The paper discusses the influence of three SAPs on fresh and hardened properties of fibre reinforced mortars containing fly ash (FRM-FA). The analysis confirmed that SAP with smaller particle sizes (< 80 µm) has a dominant influence on mitigation of autogenous shrinkage and facilitates formation of denser and more durable cementitious matrix. Despite initial strength reduction caused by collapsing SAP, mechanical characteristics of mortars are significantly improved by the prolonged hydration, facilitated by SAP and refilling of SAP pores. The effect is much more pronounced for finer polymers (< 80 µm).