The dispersion behavior of graphene oxide in cement matrix is one important factor in enhancing cement performance. In this work, we investigated the dispersion of graphene oxide in cement by simulating alkaline environment with a solution of calcium hydroxide and studied the corresponding strategy of improving dispersion. The obtained results showed that graphene oxide would flocculate even if calcium hydroxide concentration was very low, which might be the main reason of the unstable properties of the graphene oxide-doped cement. In addition, we discovered that, compared to -OH group, the -COOH group and the long chain of polycarboxylate-based superplasticizer were more effective in delaying the flocculation of graphene oxide. Finally, we proposed a dispersion mechanism of polycarboxylate-based superplasticizer. The study provides inspiration for the design of graphene oxide-doped cement materials.

A non-contacting electrical resistivity measurement device was used for measuring the electrical resistivity of early hydration samples of sulfoaluminate cement, a type of rapid-hardening cement. The early hydration process was monitored and the results show that the main early hydration of sulfoaluminate cement was accomplished within the initial 6 h. With the addition of the accelerator to improve the early strength, the hydration process was accelerated as demonstrated by the resistivity—time curve. The agent performed its role in the initial 15 min and reduced the electrical resistivity. The experimental results obtained by means of X-ray diffraction and the hydrated heat instrument were assessed to elucidate the relationship between the hydration process and the electrical resistivity of sulfoaluminate cement.