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

Abstract

The microstructure, pore structure and changes in electromagnetic parameters of cement paste prepared with nano carbon black (CB) were analysed. The results showed that 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 dispersant further enhanced the dispersion of the CB and increased its filling effect. The addition of CB also had a significant impact on the compressive strength of the cement paste, with the presence of certain CB agglomerates reducing the compressive strength. However, when the CB content (CBC) was 0.5 wt%, the use of dispersant decreased the size of CB agglomerates and effectively increased the compressive strength. Scanning electron microscopy was conducted to assess the dispersion of the CB agglomerates within the cement paste; it was found that the size and quantity of the CB agglomerates could be reduced with the addition of dispersant. The change in the CB dispersion state slightly affected the electromagnetic parameters and wave absorption properties of the cement paste. These research results offer valuable insights for the design and application of CB-dosed cement pastes.