Title:
Contact Mechanical Insight into Carbon Nanoreinforced Composites Interactions
Author(s):
Raul Marrero
Publication:
Web Session
Volume:
Issue:
Appears on pages(s):
Keywords:
DOI:
Date:
10/23/2022
Abstract:
Carbon nanoreinforcements, carbon nanofibers (CNFs) and carbon nanotubes (CNTs), have been incorporated in small percentages to cementitious matrices. These inclusions have shown enhancements in the elastic, fracture, and decrease shrinkage in the macro composite. Through Atomic Force Microscopy Quantitative Nanomechanical Mapping (AFM-QNM) and Scanning Electron Microscopy Energy Dispersive X-Ray Spectroscopy (SEM-EDS) measurements, the Interfacial Transition Zone (ITZ) between aggregate and bulk cement paste shows a localized increase in both contact modulus and presence of C-S-H rich regions compared to the bulk paste. This raises the hypothesis that carbon nanofibers through interaction with different constituents creates effect in the matrix. A different behavior not frequently observed in other micro- and macro- fibers. A modified AFM-QNM probe was developed to further understand the adhesion interactions between the carbon nanotubes and anhydrate/hydrated cement phases through a benchmarked couple SEM-EDS technique. Results shows a decrease in adhesion with lower Ca+2 concentration in C-S-H rich regions, and distinct interactions between intermix/C-S-H regions. Furthermore, gathered nanoindentation data is used to measure the effect of addition of carbon reinforcement in the creep behavior of the matrix in the submicron scales. Insights into the adhesion interactions and contact creep behavior through contact mechanics will increase the understanding of carbon nanoreinforced composite’s mechanics in the pathway for structural applications.