PSI - Issue 67

Shohana Iffat et al. / Procedia Structural Integrity 67 (2025) 1–7 Iffat et al./ Structural Integrity Procedia 00 (2024) 000–000

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• After 7 days of curing, significant enhancements (up to +45%) in compressive strength were obtained for GONR amended concrete compared to unamended concrete. In this regard, better amendment was attained using GONRs with a higher oxygen content (41.3 O%). Instead, notably, an increase in GONR concentration from 0.0005 wt% to 0.05 wt% did not result in additional strength. • Early strengthening may be attributed to accelerated and preferential cement hydration in GONR-amended concrete, in addition to physical embedment of oxidized GONRs in the cementitious matrix. • After 28 days of curing, cement hydration in the unamended concrete progressed to a point where GONR amendment produced insignificant enhancements in compressive strength. Acknowledgments This material is based upon collaborative work supported by Savannah River National Laboratory through the Laboratory Directed Research & Development (LDRD) program (Project LDRD-2020-00122), and University of South Carolina, Columbia (USC). Special thanks are extended to Ms. Laura Villegas (Ph.D. student), and personnel of the USC Structures and Materials Laboratory in the Department of Civil and Environmental Engineering, USC Center for Environmental Nanoscience and Risk in the Arnold School of Public Health, and USC Electron Microscopy Center, for the technical assistance. Author contributions The authors contributed to this paper as follows. Study conception and design: Iffat S., Gaillard J., Matta F., Meany J.; data collection: Iffat S., Elvington M., Meany J.; analysis and interpretation of results: Baalousha M., Gaillard J., Iffat S., Matta F.; draft manuscript: Iffat S., Matta F. All authors reviewed the results and approved the final version of the manuscript. References Abu Al-Rub R.K., Ashour A.I., Tyson B. M., 2012. On the Aspect Ratio Effect of Multi-Walled Carbon Nanotube Reinforcements on the Mechanical Properties of Cementitious Nanocomposites. Construction and Building Materials . 35, 647-655. https://doi.org/10.1016/j.conbuildmat.2012.04.086 Collins F., Lambert J., Duan W.H., 2012. The Influences of Admixtures on the Dispersion, Workability, and Strength of Carbon Nanotube–OPC paste mixtures. Cement and Concrete Composites . 34, 201-207. https://doi.org/10.1016/j.cemconcomp.2011.09.013 Freitas C., Muller R.H., 1998. Effect of Light and Temperature on Zeta Potential and Physical Stability in Solid Lipid Nanoparticle (SLN™) Dispersions. International Journal of Pharmaceutics . 168, 221-229. https://doi.org/10.1016/S0378-5173(98)00092-1 Hu Y., Luo D., Li P., Li Q., Sun G., 2014. Fracture Toughness Enhancement of Cement Paste with Multi-Walled Carbon Nanotubes. Construction and Building Materials . 70, 332-338. https://doi.org/10.1016/j.conbuildmat.2014.07.077 Kaur R., Kothiyal N.C., 2019. Comparative Effects of Sterically Stabilized Functionalized Carbon Nanotubes and Graphene Oxide as Reinforcing Agent on Physico-Mechanical Properties and Electrical Resistivity of Cement Nanocomposites. Construction and Building Materials . 202, 121-138. https://doi.org/10.1016/j.conbuildmat.2018.12.220 Konsta-Gdoutos M.S., Metaxa Z.S., Shah S.P., 2010. Multi-Scale Mechanical and Fracture Characteristics and Early-Age Strain Capacity of High Performance Carbon Nanotubes/Cement Nanocomposites. Cement and Concrete Composites . 32(2), 110-115. https://doi.org/10.1016/j.cemconcomp.2009.10.007 Kosynkin D.V., Higginbotham A.L., Sinitskii A., Lomeda J.R., Ayrat Dimiev A., Price B.K., Tour J.M., 2009. Longitudinal Unzipping of Carbon Nanotubes to form Graphene Nanoribbons. Nature . 458, 872-877. https://doi.org/10.1038/nature07872 Li G.Y., Wang P.M., Zhao X., 2005. Mechanical Behavior and Microstructure of Cement Composites Incorporating Surface-Treated Multi-Walled Carbon Nanotubes. Carbon . 43, 1239-1245. https://doi.org/10.1016/j.carbon.2004.12.017 Liu J., Wang L., Li Q., Xu S., 2019. Reinforcing Mechanism of Graphene and Graphene Oxide Sheets on Cement-Based Materials. Journal of Materials in Civil Engineering . 31(4), 04019014. https://doi.org/10.1061/(ASCE)MT.1943-5533.0002649 Lv S.H., Deng L.J., Yang W.Q., Zhou Q.F., Cui Y.Y., 2016. Fabrication of Polycarboxylate/Graphene Oxide Nanosheet Composites by Copolymerization for Reinforcing and Toughening Cement Composites. Cement and Concrete Composites . 66, 1-9. https://doi.org/10.1016/j.cemconcomp.2015.11.007