Effect of nano-carbon black content and dispersibility on the properties of cement paste

In this study, we analyzed the microstructure, pore structure, and changes in electromagnetic parameters of cement paste with nano-carbon black (CB) added. The following conclusions were drawn: The addition of CB significantly influenced the pore structure of the cement paste, increasing the content of pores less than 100 nm and improving the overall pore structure. The use of the dispersant further enhanced the dispersion of CB and increased its filling effect. Additionally, adding CB had a significant impact on the compressive strength of the cement paste; the presence of certain CB aggregates reduced the compressive strength. However, when the CB content was 0.5wt%, the use of the dispersant decreased the size of CB aggregates and effectively increased the compressive strength. SEM images displayed the dispersion state of CB aggregates within the cement paste, demonstrating that the size and quantity of aggregates could be reduced through the use of the dispersant. The change in the CB dispersion state also slightly affected the electromagnetic parameters and wave absorption properties of the cement paste. The research results presented in this paper offer valuable insights for the design and application of CB cement paste.