Investigation on Properties of Cementitious Materials Reinforced by Graphene

Graphene nanoplatelet has been found to be able to improve the mechanical and electrical properties of concrete so that it can make the concrete to be a "smart material". However, its effects on some other properties of graphene additive concrete, e.g., frost and corrosion resistance, remain unknown. Therefore, it cannot be directly applied in the construction practice without further investigation. The purpose of this research is to study the frost resistance and corrosion resistance of graphene additive mortar as well as the corresponding compressive strength enhancement induced by the addition of graphene. Here the tests are performed on 5 groups of mortar specimens with the same mix proportion. One group of them were cast by normal mortar, while each of the other four groups was enriched by an equal amount of C grade graphene particles (GC), C grade oxidative graphene particles (GOC), M grade graphene particles (GM) and M grade oxidative graphene particles (GOM), respectively. The dimension of the C grade graphene nanoplatelets is smaller than that of M grade graphene nanosheets. After 28 days curing, compressive strength test, Young's modulus and Poisson ratio measurement test, water absorption test, 300 cycles freezing and thawing test and 5-month corrosion test were performed. The results exhibit that the performance of the GOM group is the best among all of the experimental groups. The enhancement of the compressive strength of the GOM group is 13.2% compared to the normal mortar. The corrosion and frost resistance of cement are both slightly improved by adding the M grade oxidative graphene particles. In order to study the corresponding mechanism from the microstructure of concrete, atomic force microscopy, Raman spectroscopy and scanning electron microscopy were implemented in this research. The results of this study indicate that the oxidative graphene nanoplatelets can effectively reduce the porosity of the cementitious material and therefore increase its strength as well as the corrosion and the frost resistance