The influence of superabsorbent polymers on the mechanical and shrinkage properties of engineered geopolymer composites

Despite the excellent mechanical properties and crack control capabilities of Engineered Geopolymer Composites (EGC), they still face the challenge of high shrinkage rates in engineering applications. To address this issue, this study incorporated Superabsorbent Polymers (SAP) into EGC pastes via dry mixing and pre-absorbent mixing methods, and analyzed the effects of different SAP dosages, particle sizes, and mixing methods on the workability, mechanical properties, and shrinkage properties of EGC. The results showed that the addition of SAP effectively improved the tensile toughness and shrinkage properties of EGC, regardless of the mixing method used. The compressive strength and tensile strength of EGC with SAP dry mixing method are significantly improved, while pre-absorbent mixing showed better effects on improving the flowability, setting time, and tensile toughness of EGC. The reduction of EGC's self-contraction and early-age drying shrinkage largely depended on the particle size and dosage of SAP particles. • The flow performance and setting time of EGC mixture were studied. • The mechanical properties and shrinkage properties were studied. • The microscopic mechanism of SAP regulation was analyzed. • The drying shrinkage prediction model of EGC was established.