Enhanced early hydration and mechanical properties of cement-based materials with exfoliated layered double hydroxide

This study investigates the preparation and performance of ExLDH, synthesized from Ca-Al layered double hydroxide (Ca-Al LDH) and polymethylmethacrylate (PMMA), as a cement additive to accelerate early hydration and enhance early strength in cement-based materials. The synthesized Ca-Al/PMMA LDH was characterized using X-ray diffraction (XRD), ATR-FTIR, SEM, TEM, BET surface area analysis, and dynamic light scattering (DLS). The composite incorporated into Portland cement at 1, 2, and 3 wt. % concentrations. Isothermal calorimetry assessed hydration heat over 72 h, while microstructural evaluation employed QXRD, ATR-FTIR, TGA-DTA, SEM, and water vapor sorption tests. Mechanical properties were evaluated through compressive and flexural strength tests.

Results confirmed the successful fabrication of ExLDH micro/nano-composites, which serve a dual role in the cement matrix: acting as nucleation sites for hydrated phases and as void fillers to improve structural compaction. This dual effect accelerates hydration, increases hydrated phase content, and significantly enhances compressive strength and structural density.