LAUSR

Abstract The cellulose nano whiskers (CNWs) due to their fibrous shape and high crystalline nature seemed to be suitable as reinforcement for cementitious materials. In this research acid hydrolysis were used along with mechanical stirring and sonication to prepare cellulose nano whiskers (CNWs). Prepared nano whiskers were characterized for chemical and crystalline structure, particle size and morphology of micro/nano structure. Then, they were used as reinforcement in a fine aggregate concrete (FAC) at 0, 0.5, 1 and 1.5 vol%. Flexural behavior of the samples was evaluated by a three-point bending test. Moreover, some combinations of CNW and polyvinyl alcohol (PVA) fiber were used as reinforcement of concrete. By adding the CNW at high proportion of PVA fibers, the flexural properties of composite decreased, while, at lower contents of PVA fiber, flexural strength enhanced about 20%. Addition of CNW generally improved flexural properties of FAC, but made it more brittle. Utilizing hybrid of CNW with PVA fibers in the samples decreased the first and second cracking loads up to 40% but still retained its flexural hardening behavior such as engineered cementitious concretes.