Microstructure and transport properties of cement-based material enhanced by graphene oxide

Abstract

Microstructure and transport properties of graphene oxide (GO)-cement mortars with similar consistency were experimentally investigated and compared with those of control mortars that were made using Portland cement. Polycarboxylate superplasticizer (PCs) was used to improve the consistency of GO-modified mortars and the dispersibility of GO nanosheets. Results indicate that the GO-incorporating mortars with similar consistency reduce the chloride migration coefficient and the initial rate of water absorption by 33.2% and 61.6% compared with the control samples, respectively. This improvement is due to the addition of GO particles in the mortars which inhibit crack growth, change the morphology of hydrated crystals and refine the pore structure. Meanwhile, very small amounts of GO additives can significantly decrease the macropore volume fraction and the critical as well as average pore diameters. To understand the correlation between the pore-size distribution and the macroscopic transport performance, both the critical pore diameter and the macropore volume fraction have been proved to be exponentially dependent on chloride migration coefficient. The average pore diameter is linearly related to the initial absorption rate of the mortars, but is independent of the secondary absorption rate.