Hydration Products and Properties of Nanocellulose Fibre-Reinforced Mortar

This study investigates the influence of nanocellulose fibre (CF) derived from wood pulp on the hydration, mechanical, shrinkage, and pore properties of ordinary Portland cement (OPC) mortar. The CF was incorporated into mortar mixes at varying dosages (0.15–1.5% by weight of mortar) to evaluate its effect on physical, mechanical, and microstructure properties. X-ray diffraction (XRD), thermogravimetric analysis (TGA/DTG), and mercury intrusion porosimetry (MIP) were employed to assess the hydration phases and microstructural changes induced by the CF addition. Experimental results indicate that CF alters the hydration kinetics of cement mortar by influencing the formation of hydration products such as calcium silicate hydrate (C-S-H), portlandite (CH), and carbonate phases. The introduction of CF enhances crack resistance and shrinkage control, particularly at an optimal dosage of 0.45%, which exhibited reduced drying shrinkage and improved phase stability. While CF incorporation had minimal impact on compressive and flexural strength at lower dosages (≤0.45%), higher CF contents (>0.99%) caused pore structure modifications, leading to an increase in total porosity and a reduction in strength. The XRD analysis revealed that CF does not introduce new hydration phases but modifies the crystallinity of existing phases. The hydration behaviour, as indicated by TGA/DTG, showed an increase in bound water content at moderate CF dosages, suggesting enhanced internal curing and prolonged hydration. Overall, the findings demonstrate that CF is a viable sustainable additive for cementitious materials, offering advantages in shrinkage control, hydration enhancement, and durability improvement. The results suggest that an optimal CF dosage of 0.45% provides a balance between workability, mechanical properties, and durability, making it an effective additive for enhancing the performance of OPC mortars in sustainable construction applications.