Incorporation of Cellulose Nanocrystals Synthesized from Rice Husk in Engineered Cementitious Composites

Abstract

Engineered cementitious composites (ECCs), belonging to the class of high-performance fiber reinforced cementitious composites, are distinguished by their exceptional tensile strain capacity. However, practicality concerns have prompted the exploration of alternative components in their fabrication, sometimes compromising their mechanical properties. This study investigates the influence of cellulose nanocrystals (CNCs) on the mechanical properties of two types of ECC mixtures: the M-0 mixture, which uses locally sourced materials, and the M-50 mixture, which incorporates sugarcane bagasse ash. CNCs were added to these ECCs in varying concentrations of 0.5, 1.0, 1.5, and 2.0 wt.% of cement, synthesized from rice husk via an acid hydrolysis process. Characterization techniques, such as X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy, and thermogravimetric analysis, were employed to analyze the nanocrystals of CNCs. Compression and tension tests were performed to evaluate the mechanical properties of the M-0 and M-50 mixtures, followed by flexural testing on the mixtures with the most promising tensile properties. TEM analysis indicated that CNCs have an aspect ratio ranging from 7 to 14, while XRD results confirmed a crystallinity index of 55% for CNCs. Notably, CNCs were found to significantly enhance the compressive strength of both the M-0 and M-50 mixtures. Furthermore, the addition of CNCs to the M-50 mixtures resulted in an impressive high strain capacity of 3.24%.