Preparation and Durability of Cement-Based Composites Doped with Multi-Walled Carbon Nanotubes

In this paper, the durability and microstructure of cement-based composites doped with multi-walled carbon nanotubes (MWNTs) were investigated with low MWNTs concentration of 0, 0.05%, 0.1% and 0.15% by weight of cement at 28 days. Ultrasonic processing and a commercially surfactant (Gum Arabic, (GA)) were utilized to achieve homogenous MWNTs suspensions. Chloride ion penetration resistance, sulfate attack resistance, and scanning electron microscopy (SEM) were used to characterize the durability of cement-based composites with MWNTs. Compared with the reference sample, the addition of MWNTs improved the chloride ion penetration resistance performance, sulfate attack resistance and microstructure of cement composites. The 0.1% weight fraction of MWNTs obtained excellent durability among the composites. The embedded MWNTs acted as bridges and networks across the voids and cracks in matrix, which guaranteed the load-transfer in case of tension.