Cellulose nanocrystals lime mortar based on biomimetic mineralization

Sticky rice-lime mortar has been widely used in the construction of traditional buildings. It has been known as the best available material for restoring ancient buildings. However, it is unbenevolent to use edible sticky rice for a large scale restoration considering hunger crises. In addition, the component of sticky rice is complex, the mechanism of how sticky rice mediates the properties of lime mortar is still unclear. In this work, as a kind of abundant, inedible and single-component polysaccharide, nematic cellulose nanocrystals (CNCs) were used to prepare lime mortars. The characteristics, such as compressive strength, molar percent of calcium carbonate, microscopic morphology, of lime mortars were characterized to explore the function of CNCs in lime mortars. Compressive strength is related to molar percent of calcium carbonate and the organization of CNCs. The main polymorph of calcium carbonate is calcite. Rod-like CNCs orient themselves in one direction and control calcium carbonate to grow along the particular direction of CNCs orientation based on biomimetic mineralization. External force field further organizes CNCs and the growth of calcium carbonate. It is promising to restore ancient building with lime mortar containing CNCs since the properties, such as compressive strength and polymorph of calcium carbonate, of lime mortar added CNCs are similar to that of traditional sticky rice-lime mortar. Additionally, the mechanism of biomimetic mineralization process of CNCs is clear. Our work opens a way to develop traditional material with new technology and new materials.

Automated summary

Sticky rice-lime mortar has been widely used in traditional buildings, but its edible nature and complex composition restrict its large-scale use. In this study, cellulose nanocrystals were used as a substitute material to prepare lime mortars with similar properties to traditional sticky rice-lime mortar. The organization of cellulose nanocrystals and the molar percent of calcium carbonate were found to be closely related to the compressive strength of lime mortars.