Early-age shrinkage strain measurements of the graphene oxide modified magnesium potassium phosphate cement

Abstract

In this paper, a novel early-age shrinkage measurement method was used to investigate the influence of graphene oxide (GO) additive on the magnesium potassium phosphate cement (MKPC) mortar. Temperature and shrinkage strain of the MKPC mortar were simultaneously measured by using fiber Bragg grating sensors during the hydration process. The early age setting time of cement samples was determined by temperature records, which showed with the increasing content of GO the early age setting time is decreased. Through the measurement approach, conclusions also can be drawn that with an increase in the amount of GO, the early-age shrinkage strain of the MKPC paste decreases initially and subsequently increases. The MKPC mixture containing 0.06 wt% of GO possessed minimum shrinkage strain variation on the whole hydration reaction. The reasons for this phenomenon were fully discussed in the paper. Scanning electron microscopy and energy dispersive spectrometer were used in another test to prove the inference.