Effect of plant cellulose microfibers on hydration of cement composites

Abstract

This study investigated the hydration characteristics of cement composites incorporating plant cellulose microfibers (CMFs) as a sustainable additive. The main test variables were the size and amount of CMFs. Two different CMF sizes were fabricated from kenaf strand fibers, and their average lengths were approximately 5 mm and 400 μm, respectively. The amount of CMFs varied from 0 to 2 wt% of the cement. The amount of water required to saturate the CMFs was considered in the mix proportions of cement composites. The hydration characteristics were assessed by the setting time, heat of hydration, compressive strength, mercury intrusion porosimetry, and scanning electron microscopy. The use of higher amount of CMFs led to a larger delay in the setting time and early-age hydration of the cement composites, and of the two sizes, smaller-sized CMFs caused a further delay. A higher ratio of CMFs generally caused a lower compressive strength, but the mixtures with 0.3–0.6% CMFs showed reasonably high (about 85–90%) strengths compared with the plain mixture. The CMFs refined the pore structures of the cement composites, which was associated with the nucleation of hydrated phases and further hydration due to the release of water present in the fibers. © 2020 Elsevier Ltd