Synergistic effect of MWCNTs and GO as a reinforcing phase on copper slag-based cement composites

This study utilized solid waste-copper slag to substitute 30% cement to produce composite cementitious materials. To achieve the desired performance standards, single-doped PPF or CF, and single-doped or double-doped multi-wall carbon nanotubes (MWCNTs)/graphene oxide (GO) have been used as reinforcing materials to prepare environmentally friendly copper slag-based cement (CSC) composites. SEM analysis was conducted to investigate and assess the ordered structure of MWCNTs and GO. Subsequently, a solution of MWCNT/GO nanoparticles was generated by dispersing MWCNT/GO with a gum Arabic (AG) surfactant. Following ultrasonic treatment, the clear liquid was collected and combined with 30% solid waste copper slag and 70% cement to form a composite cementitious matrix. The inclusion of carbon nanomaterials enhanced the sample's compressive strength by over 41.6% compared to the control samples. It was equivalent to 97.1% of blank group C0, and the bending strength was about 93.8% of C0 group of the same age. In addition, the hydration products, gelation and crystallization, pore structure and microstructure of CSC materials were analyzed by quantitative X-ray diffraction (QXRD), scanning electron microscopy (SEM), fourier transform infrared (FTIR) spectroscopy, and nitrogen adsorption specific surface area and porosity measurement (BET). The CSC sample, with double-doped optimized MWCNT/GO exhibited the most favorable microstructure and strongest nucleation effect. As a result, the hydration degree of the CSC cementitious material was improved, which contributed to the formation of a greater amount of amorphous calcium-silicate-hydrate (C-S-H) phase, a finer C-A-S-H phase. The samples doping a combination of MWCNTs and GO exhibited synergistic enhancement. This novel nanocomposite cementitious material incorporated carbon nanoparticles into the mixture with solid waste, resulting in a solid composite cementitious material. The production of reinforced concrete is based on solid waste and demonstrates significant environmental advantages.