Effect of Super Absorbent Polymers on Shrinkage and Hydration Properties of High-performance Cement-based Composites

Based on the shrinkage problem of high-performance concrete in high-altitude dry environments,the effects of different dosage of the anionic polyacrylamide polyacrylate superabsorbent polymers (SAP-YF)and a commercial polypropylene-based super absorbent polymers (SAPS)on the shrinkage properties of cement-based materials under high-altitude dry environment were studied. The test results showed that with an increase in SAP dosage,the autogenous shrinkage and strength of the cement-based materials gradually decreased,while the drying shrinkage remained relatively unchanged. Considering the premise of not affecting the strength and minimizing shrinkage,the optimal dosage of SAP-YF was 0. 20% under a water-cement ratio of 0. 20,with a shrinkage reduction rate of 28. 21%. XRD and TG results showed that the hydration degree and solid phase composition of the SAP-containing specimens exhibited significant improvements compared to the control group after 7 d of curing. The introduction of SAP helped maintain the internal moisture content of the paste matrix,creating an environment conducive to the hydration of cementitious materials for 7 d or more. The inclusion of SAP accelerated the early hydration process of cementitious materials. Based on XRD,TG experiments,and theoretical research,a model for the evolution of solid-phase composition of cement-based materials containing SAP with curing time under dry conditions was established,which could provide data support for thermodynamic model calculations and concrete mix design in high-altitude dry environments. © 2024 Cailiao Daobaoshe/ Materials Review. All rights reserved.