Influence of Raw Material Size on the Microstructure of Graphene Oxide and Its Early Strengthening Properties of Cemen

Abstract

With the purpose of exploring the influence of raw material size on the structure-performance of graphene oxide (GO) for cement reinforcement, this paper used natural flaked graphite with different particle sizes as raw material to prepare GO nanosheets by a method of enhanced Hummers, and then used scanning electron microscope (SEM) , X-ray diffraction (XRD) , Raman spectrum, infrared spectrum (IR) and other means to characterise the microstructure of GO products in detail, and then investigated the effects of raw material size and graphene oxide GO dosage on its early strengthening effect in cement. The experimental results showed that with the decrease of raw material particle size, the spacing between the layers of GO products is basically the same, while the oxidization degree is increased, and the oxygen-containing groups on the surface are increased. When the GO matt was used to prepare cement mortar with same GO extent, the mechanical strengths at an age of 3 days were found to initially increase and then decrease with the reduction of raw material particle size, and the GO products had the best effect on the improvement of early mechanical strength of cement when the raw material particle size was 13μm. On the other hand, GO matt being obtained from the raw material particles in a size of 13μm was employed to prepare cement mortar with different GO content, of which the 3d strength was found to increase apparently with the increasing GO content, and thus resulted in the increment of 8. 85% to the 3d compressive strength and 6. 34% to the 3d flexural strength for the mortar specimen obtained with a GO content of about 0. 05%, but the further increasing of the GO content is not proposed, which might gave rise of a relative low mechanical strength.