Abstract
This study evaluated the potential effect of cellulose nanocrystal and coated polyethylene fiber on the mechanical properties of mortar. Two kinds of cellulose nanocrystals (CNC) directly as Nano-materials, and indirectly as film coated onto the polypropylene fibers were employed as cement-based reinforcement materials. The fluidity, flexural and compressive strength, and the microstructure of each specimen were measured. In the direct method, mortar mixed with the CNC containing carboxyl groups (CNC-C) showed superior properties compared to the CNC containing sulfo groups (CNC-S). The addition of CNC impacted the process of hydration and compactness of hydration products. The results of X-Ray polycrystalline diffractometer (XRD) and heat of hydration showed that CNC accelerated hydration process. Energy spectrum analysis (EDS) measured ratio of calcium to silicon (C/S) of calcium silicate hydrate (C-S-H) and proved that CNC-C increased the tightness of C-S-H while CNC-S decreased. The results of scanning electron microscopy (SEM) indicated that cellulose nanocrystals were interspersed in C-S-H, forming Nano-bridge and arresting Nano-crack. In the indirect method, the maximum increase in flexural strength of sample between all groups was the specimen that adding 0.3% (volume ratio of fiber to mortar) of CNC-C coated polypropylene fibers. The flexural and compressive strength of the mortar were increased by 22.81% and 10.65% compared to the control, respectively. The results of SEM indicated that coating enhanced bond of the fibers/matrix. Molecular dynamics simulation (MD) analyzed the binding energy, microstructure, dynamic characteristics and adsorption conformation between two CNCs and C-S-H at the molecular scale. MD presented clearly that the adsorption energy between CNC-S and C-S-H was much smaller than CNC-C and C-S-H. This was identical with CNC-C enhancing the mechanical properties of the mortar and CNC-S reducing the mechanical properties.
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Disclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.