Effects of Multi-Walled Carbon Nanotubes and Recycled Fine Aggregates on the Multi-Generational Cycle Properties of Reactive Powder Concrete

In order to investigate the effect of multi-walled carbon nanotubes (MWCNTs) on the recyclable properties of multi-generation recycled concrete, the physical properties of multi-generation recycled fine aggregate and the mechanical properties of multi-generation recycled concrete with different dosages of MWCNTs were tested, and the enhancement mechanism was analyzed by scanning electron microscopy (SEM). The results showed that the apparent density of multi-generation recycled fine aggregate with 0.05 wt% MWCNTs was increased by 1.04 similar to 2.03%, the crushing value was decreased by 38.21 similar to 49.45%, the compressive strength of the concrete prepared by it was increased by 11.11 similar to 18.96%, the splitting tensile strength was increased by 10 similar to 43.94%, the flexural strength was increased by 13.62 similar to 22.23%, and the mechanical properties were analyzed by scanning electron microscopy (SEM). Combined with the scanning electron microscope image analysis, the MWCNTs can fill the pores inside the specimen, bridge the cracks, and retard the decrease in concrete strength after multi-generation recycling.