Multi-scale experimental studies on mechanical properties of three-dimensional porous graphene cementitious composite

This study aimed to reveal the influence of 3D porous graphene on the cementitious composites from multiple scales. At the macro level, the 3D porous graphene could greatly improve the strength, elastic modulus, and crack resistance of the cementitious composite. At the micro level, the nanoindentation test indicated that the thickness of the interfacial transition zone (ITZ) could be reduced by adding 3D porous graphene, and the microcracks and pores could be lowered as well, which led to mechanical enhancement. Besides, statistical nanoindentation technique (SNT), X-ray diffraction (XRD), isothermal calorimetry, energy dispersive spectroscopy (EDS), and scanning electron microscope (SEM) evidenced that the 3D porous graphene could promote cement hydration and strengthen the elastic modulus and hardness of hydration products. Embedded in the hydration products, the 3D porous graphene could fill the cracks and pores and anchor the cement matrix at the micro-scale, which exhibited the reason for the positive effect caused by the 3D porous graphene at the macro-scale.