Regulation of GO on cement hydration crystals and its toughening effect

Abstract

An aqueous dispersion of graphene oxide (GO) nanosheets with different oxygen content was obtained from graphite via oxidation and ultrasonication. The effects of GO nanosheets on the microstructure and mechanical properties of hardened cement paste were determined by scanning electron microscope, X-ray diffractometer and tensile/flexural/compressive strength investigations. The results indicate that GO nanosheets can regulate the formation of flower-like crystals and distinctly improve the tensile, flexural and compressive strengths of the corresponding hardened cement paste: when the oxygen content of GO was 25 . 45% and its dosage was 0 . 02% by weight of cement, the tensile strength and flexural strength increased by 197 . 2% and 184 . 5% respectively. These results suggest that GO nanosheets can significantly improve the toughness of hardened cement paste. A working mechanism is proposed by which GO may regulate the formation of hydration crystals by a template effect and thus exhibit significantly enhanced flexibility. The research results provide a potential new pathway to improve the toughness and reduce the cracking of cement composites.

Incorporating graphene oxide in cement composites: A study of transport properties

“…5a [18]. This phenomenon has been observed by other researchers as well [25]. Other researchers Panzavolta [26] have stated that graphene and graphene oxide based composites fabrication has a major issue of restacking graphene sheets because poor interaction with the matrix.…”

Influence of Graphene Nanosheets on Rheology, Microstructure, Strength Development and Self-Sensing Properties of Cement Based Composites

“…We would like to mention here that from visual inspection and UV-vis spectra, it was found that the GO sheets were well dispersed in aqueous solution even after 2 h. (b) Bond formation between cement matrix and GO sheets: The increase in compressive strength of GO-cement composite could be endorsed to the strong bond between the cement matrix and GO. The surface of GO contains many oxygen functional groups -OH and -COOH, which form a strong covalent bond with C-S-H and CH [53,54]. The presence of the chemical interaction was also observed in the FTIR spectra and TGA/DTA data.…”

Effect of graphene oxide on the rheological properties of cement pastes

“…9). The microstructure is changed with the increasing GO dosages, which is explained in Lv's research [18,19].…”

“…Consequently, GO shows a better gain in compressive strength at a lower concentration when compared to CNT reinforced cement [12]. The introduction of GO in cement not only can regulate hydration but also improve the tensile, flexural and compressive strengths of the cement paste [8,[18][19][20][21][22]. Lv et al [19] discovered that when the content of GO was 0.03%, the cement composites exhibited remarkable increase in tensile strength (78.6%), flexural strength (60.7%) and compressive strength (38.9%).…”