Effect of multiscale cellulose fiber-crystalline microcelulose reinforced on the hydration phase of Portland cement pastes

ABSTRACT

The use of cellulose fibers in cement matrix can present an inhibitory effect causing chemical incompatibility. The production process of civil construction materials reinforced with cellulose fibers can be rendered unfeasible. On the other hand, microcelluloses usually accelerate the production of calcium silicate hydrate gel (CSH) accelerating the cement hydration degree. The present work aims at understanding the combined interactions between crystalline microcellulose and cellulose fiber (MCC and FC) in the hydration process of cement pastes. The results obtained in the paste inhibition test pointed out a good compatibility of cellulose fibers and the FC/MCC system with cement pastes. For cement pastes with fly ash substitution, the FC/0,6%MCC system showed moderate inhibition with a statistically significant difference from the other treatments. Through the X-ray diffraction test it was possible to conclude that both cellulosic fibers and the FC/MCC system did not influence the mineralogy of the composites, where the diffraction patterns showed the typical hydration products of mineral binders. In the XRD analysis it was possible to identify the reduction of the Portlandite magnitude peaks, with the incorporation of cellulose MCC in the cement pastes.

Keywords
Cellulose materials; Reinforcement systems; Mineral binders