Effects of graphene oxide on chloride ion penetration and microstructure of coral-sand cement stones

Abstract

The coral-sand (CS) foundations built in the marine environment inevitably suffer from chemical invasion of seawater. Graphene oxide (GO) has been considered as a feasible additive to improve chloride penetration ability of cement mortar, but limited studies have been carried out on GO-modified CS cement stones. In this study, a series of rapid chloride migration (RCM) tests were respectively conducted on CS or river-sand (RS) cement stones with various GO contents. Meanwhile, scanning electron microscope (SEM) tests were also performed to study microscopic features of the cement stones. Experimental results revealed that the chloride migration coefficient D_RCM for both CS and RS samples firstly decreased and then increased with increasing GO content. The lowest D_RCM values were achieved while adding 0.02 wt% GO for CS samples and 0.03 wt% GO for RS samples. Meanwhile, the D_RCM values of CS samples were higher than those of RS samples at a given GO content. Microstructural results demonstrated that as the GO content increased, the shape of hydration crystals gradually transformed from a needle-like shape to a flower-like shape. The addition of GO could promote hydration products to fill the holes inside the cement stones, effectively inhibiting the chloride ion penetration.

Keywords:

• Coral-sand cement stones
• graphene oxide
• hydration products
• microstructure

Disclosure statement

No potential conflict of interest was reported by the authors

Additional information

Funding

The authors are grateful to the National Natural Science Foundation of China (Projects No. 51774131 and 41972282), Hunan Innovative Province Construction Special Project (Project No. 2019RS1059) for the financial support.