Development and Evaluation of Engineered Nanocellulose-Based Mortar Synthesized Using Hydrolysis of Strong and Weak Acids

Abstract

Engineers constantly seek innovative techniques to incorporate existing materials to perform better and attain sustainability. Owing to the high aspect ratio and mechanical strength, nanostructured cellulose may help the development of a value-added construction product. In this study, two kinds of cellulose nanocrystals (CNCs), synthesized using strong hydrochloric acid (HCl) (CNC-H) and weak formic acid (CH2O2) (CNC-F) having crystallinities of 89.89% and 92.61%, diameters of 1 μm and 15–17 μm, lengths 10–40 μm and 87 μm, and solid to acid ratios of 1 g:10 ml and 1 g:25 ml, respectively, were incorporated as a green additive (0–1% by wt. of cement) in the production of mortar. The performance of the fabricated mortar samples was determined by flow, compressive strength, and volume of permeable pore space tests. The outcomes were endorsed by analytical tests. The overall performance of CNC-H outperformed CNC-F. A linear drop was noticed in the flow of fresh mortar with the increase in the content of CNCs because of agglomeration governed by their particle proportions. The highest compressive strengths and least volume of voids were recorded in CNC-H samples (41.1 MPa and 13.6%), respectively. These values were 19.5% greater and 18.6% lesser than that of CNC-free control samples, respectively. The factors contributing to the improved performance of CNC-H specimens included lower crystallinity of material and the enhanced interlocking effect among ingredients in cementitious composites, as evident from the X-ray and SEM analysis. On contrary, the poor performance of CNC-F specimens was attributed to the incomplete degradation of cellulose domain due to weak hydrolysis. It is suggested that CNC-H mortar has an enormous possibility as an additive in the construction industry in technical, environmental, commercial, and industrial ways.