Abstract

As the global construction industry moves toward more environmentally responsible solutions, achieving both durability and sustainability goals in cement-based materials has become increasingly important. One of the main challenges in this effort is to effectively and economically achieve the desired levels of workability and strength of sustainably designed mixtures, controlling their early-age shrinkage, which can reduce long-term performance and service life. This study explores the integration of superabsorbent polymers (SAPs), a promising internal curing agent, into plain and slag-cement mortar systems made with Type IL cement to enhance their dimensional stability while promoting sustainability. The experimental program evaluates mortars modified with 0.2% SAP by weight of binder and colloidal nanosilica in both plain Type IL and slag-blended binder systems at constant water -binder (w/b) ratio of 0.44. The scope of the study included evaluation of fresh properties (workability and air content), strength development (flexural and compressive), changes in stiffness (using ultrasonic pulse velocity measurements) and shrinkage (autogenous and drying). Results indicate that the incorporation of SAP significantly improved the strength and stiffness of mortar mixtures. The incorporation of SAP also mitigated drying shrinkage, particularly in slag-modified mixes, which are typically more susceptible to volumetric changes due to their finer pore structure and lower early-age rate of strength development. Autogenous shrinkage measurements show that the initial phase of shrinking, the SAP-modified mixtures displayed rapid stabilisation of deformations, reflecting the onset of water release. This implies that SAP effectively fulfils its internal curing function by providing additional water during the critical period of autogenous strain development. The overall findings reinforce the viability of using SAPs to balance performance and sustainability objectives, especially in mixtures using supplementary cementitious materials.

Keywords

superabsorbent polymers, internal curing, slag-cement, drying shrinkage, autogenous shrinkage.

DOI

10.5703/1288284318136

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Influence of Superabsorbent Polymer on Workability, Strength, and Shrinkage of Mortars with Plain and Slag-Cement Binders

As the global construction industry moves toward more environmentally responsible solutions, achieving both durability and sustainability goals in cement-based materials has become increasingly important. One of the main challenges in this effort is to effectively and economically achieve the desired levels of workability and strength of sustainably designed mixtures, controlling their early-age shrinkage, which can reduce long-term performance and service life. This study explores the integration of superabsorbent polymers (SAPs), a promising internal curing agent, into plain and slag-cement mortar systems made with Type IL cement to enhance their dimensional stability while promoting sustainability. The experimental program evaluates mortars modified with 0.2% SAP by weight of binder and colloidal nanosilica in both plain Type IL and slag-blended binder systems at constant water -binder (w/b) ratio of 0.44. The scope of the study included evaluation of fresh properties (workability and air content), strength development (flexural and compressive), changes in stiffness (using ultrasonic pulse velocity measurements) and shrinkage (autogenous and drying). Results indicate that the incorporation of SAP significantly improved the strength and stiffness of mortar mixtures. The incorporation of SAP also mitigated drying shrinkage, particularly in slag-modified mixes, which are typically more susceptible to volumetric changes due to their finer pore structure and lower early-age rate of strength development. Autogenous shrinkage measurements show that the initial phase of shrinking, the SAP-modified mixtures displayed rapid stabilisation of deformations, reflecting the onset of water release. This implies that SAP effectively fulfils its internal curing function by providing additional water during the critical period of autogenous strain development. The overall findings reinforce the viability of using SAPs to balance performance and sustainability objectives, especially in mixtures using supplementary cementitious materials.