Investigation into the Impact of Graphene Oxide (GO) on Microstructural Characteristics in Geopolymer Composites Derived from Fly Ash

This work reports on the effect of adding GO on the microstructural properties of fly ash-based geopolymer-GO composites. Scanning electron microscopy (SEM), X-ray diffraction (XRD), and Fourier Transform Infrared (FTIR) tests were performed to investigate microstructural properties of fly ash-based geopolymer-GO composites. The XRD data showed that the intensity of the peaks in the fly ash-based geopolymer-GO composites increase with increasing the amount of the GO composition, which indicates the quartz phase (SiO 2 ) remained in crystal form. Fourier Transform Infrared (FTIR) data showed that the presence of GO absorption bands indicates the successful inclusion of GO into the geopolymer matrix/network, which affected the microstructural development of fly ash-based geopolymer-GO composites. In addition, the SEM images reveal that fly ash's diameter decreased up to the GO content of 1 gram, and the matrix was denser, which will increase the strength of the fly ash-based geopolymer-GO composites. While adding larger than 1 gram (e.g., 2 grams) of GO results in a bigger diameter of fly ash with the coarser matrix, which will decrease the strength of the fly ash-based geopolymer-GO composites.