Holistic effect of GO@ZIF-8 nanohybrids in LC³-based mortar

Limestone calcined clay cement (LC³) offers a low-carbon alternative to Portland cement but has limitations, including drying shrinkage and reduced early compressive strength. This study explores nanohybrids to enhance LC³ mortar properties. A new hybrid of graphene oxide and zeolitic imidazolate framework-8 (GO@ZIF-8) was synthesized and added to LC³ mortar in varying dosages. Tests on hardened LC³ mortar measured improvements in compressive strength, drying shrinkage, water absorption, heat of hydration, and microstructure. Results showed 0.2 wt% GO@ZIF-8 increased compressive strength slightly by 2.9 % and reduced drying shrinkage by 9.1 %, though porosity rose by 6.67 %, and water absorption increased from 2.8 % (control) to 3.06 % and 3.20 % with 0.2 and 0.4 wt% GO@ZIF-8. Adding 0.3 wt% accelerated Phase II hydration, enhancing hydration products and crystallinity in LC³ mortar, confirmed by SEM images showing a densified microstructure with well-dispersed GO@ZIF-8 particles. Additionally, thermogravimetric analysis confirmed that GO@ZIF-8 incorporation enhances hydration efficiency. However, higher dosages led to microstructural defects, reducing strength, and highlighting the need for dosage optimization. This research demonstrates the potential of nanohybrid, like GO@ZIF-8, to improve construction materials, although single nanoparticles may offer a more sustainable approach.