Effect of graphene oxide (GO) on hydration of tricalcium silicate (C3S).

Highlights • GO addition decreases mean chain length of C-S-H gel. • GO addition enhances hydration degree up to approximately 20%. • GO addition refines the microstructure of C 3 S paste. Abstract In this study, the interaction between the major phase of cement clinker, C 3 S, and GO was explored to investigate its effect on the microstructures of G 3 S/GO composites at different GO dosages in a range of 0–0.05 wt%. The compressive strength of C 3 S/GO composites was tested and their microstructural developments were analyzed by scanning electron microscope (SEM), X-ray diffraction (XRD), thermogravimetric analysis (TG), nitrogen adsorption and 29Si solid-state nuclear magnetic resonance (NMR) techniques. The results show that the addition of GO can improve the compressive strength of C 3 S/GO paste up to 32.5% at 1 day. In addition, the incorporation of GO provided an increasing number of nucleation sites to form denser microstructure and refined the pore structure by reducing the total porosity and increasing the gel pores. In particular, the hydration degree was increased by approximately 20% at the age of 7 days when the GO dosage was in the range of 0.03–0.05 wt% as evidenced by TG and NMR results. The ratio of Q2/Q1 in C-S-H gel decreased slightly with the increased GO content, which was further corresponding to the decreased mean chain length of C-S-H gel. Therefore, the introduction of GO exerts a positive effect on the hydration of C 3 S, which provides essential supports to the hydration mechanism of GO in Portland cement matrix. [ABSTRACT FROM AUTHOR]