Internal curing of natural hydraulic lime with superabsorbent polymers

An Investigation into the Performances of Cement Mortar Incorporating Superabsorbent Polymer Synthesized with Kaolin

“…The results demonstrate that in the K-SAP group, the quantity of medium capillary pores is significantly reduced, while the number of fine capillary pores and macropores is increased. This observation aligns with the findings of Li et al [25]. The reasons are straightforward: K-SAP, acting as an internal curing agent, consistently releases water during the cement mortar hydration process, promoting internal hydration of the cement mortar.…”

“…The weight loss peak within the 600°C-650°C range corresponds to the decomposition of calcium carbonate, indicating that carbonation during the curing process transforms Ca(OH) 2 into calcium carbonate. This observation further suggests that K-SAP promotes the hydration of the cement mortar [25].…”

“…Throughout the cement hydration process, it consistently releases water to supplement the required hydration, resulting in volume shrinkage and the creation of numerous voids within the cement mortar. This inherently diminishes its own strength [25,29,33]. Secondly, during the initial water-release stage, K-SAP proportionately raises the effective water-cement ratio in the interfacial transition zone.…”

“…This implies ongoing thickening of the cement mortar, with cement hydration becoming the dominant factor in the increase in shear stress. Some studies have suggested that multiple experiments may impede the formation of hydration flocculation structures, and the use of highly efficient water reducers can contribute to a reduction in the initial yield stress [25].…”

“…The reasons are straightforward: K-SAP, acting as an internal curing agent, consistently releases water during the cement mortar hydration process, promoting internal hydration of the cement mortar. Additionally, the inorganic active particles in kaolin clay, through reactions with Ca 2+ in the cementitious matrix, generate hydration products such as C-S-H gel, further densifying the pore structure [25,29]. These two factors collaborate to optimize the pore structure, specifically transforming medium capillary pores into fine capillary pores and fine capillary pores into gel pores.…”