Synergetic Effect of Expansive Agent (KEA) and Superabsorbent Polymers (SAP) on the Shrinkage, Strength and Pore Structures of Mortars

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In this work, the effects of the individual or hybrid addition of superabsorbent polymers (SAP) with varying dosages (0.1%, 0.2%, 0.3%, and 0.6%) and the lime-type expansive agent (KEA) on the length and mass change, compressive strength, and pore structures (MIP) of mortars were investigated. The results showed that the incorporation of SAP can effectively mitigate its autogenous shrinkage and the length change value of the mortar with SAP smaller than reference until 49 days, regardless of the presence of KEA. The hybrid addition of SAP and KEA increases the initial expansion of the specimens as compared with individual addition of SAP, which is a beneficial effect on compensating for the shrinkage of the mortar under drying conditions. Moreover, the addition of SAP seems to delay cement hydration and increase the volume of macropores (greater than 100 nm), thereby reducing the compressive strength of the mortars. The introduction of KEA slightly promoted the formation of micropores, resulting in a slight increase in compressive strength compared with the samples without KEA. Furthermore, in our view, it promotes pore refinement, so as to reduce moisture evaporation.

Ce résumé expose les affirmations des auteurs. BNTIC ne l’interprète pas comme une validation indépendante des résultats.