Effect and mechanism of graphene nanoplatelets on hydration reaction, mechanical properties and microstructure of cement composites

Graphene nanoplatelets (GNPs) with extraordinary mechanical properties have been widely cooperated in special and high-performance composites. However, the impact of GNPs on hydration process in cement composites is still ambiguous and controversial. In this research, the GNPs was dispersed by dispersants with ultrasonication. The GNPs/cement composites were prepared and their hydration process were monitored by isothermal calorimetry (TAM Air) and Si-29 NMR analysis. In addition, the pore structure and microstructure of GNPs/cement composites were tested with Mercury intrusion porosimeter (MIP) and Scanning electron microscope (SEM). And phase analysis was discussed by analysis of XRD and TG/DTG spectrums. The experimental results suggest that GNPs may contribute to accelerate the hydration reaction and more hydration products generated because of sufficient ion exchange in earlier ages and in this basis, a more compact microstructure and better mechanical properties of GNPs cement composites achieved. (C) 2019 Elsevier Ltd. All rights reserved.