Simple model for predicting compressive strength of cement composites using carbon nanotubes based on cement hydration

To determine the effect of carbon nanotube (CNT) on cement hydration, this study defines the hydration mechanism of CNT-cement composites and presents a model, in the form of a simple equation, for predicting the initial and long-term compressive strengths of the CNT-cement composites. The hydration acceleration effect of CNTs is modeled by extending the CEMHYD 3D model to the nanoscale. This approach provides a method for modeling the initial microstructure that can be applied during the cement hydration process. The impact of CNTs on cement hydration reactions is analyzed numerically using the proposed method for microstructure formation. The numerical analysis results are applied to the simple model for predicting compressive strength based on hydration, and the hydration acceleration effect of CNTs is approximately 10%. The hydration analysis model for predicting compressive strength is based on the Parrot and Killoh model. Reflecting the hydration acceleration effect of CNTs, the model is configured to predict initial and long-term compressive strengths because of increased hydration levels. The proposed model reflects the hydration acceleration effect of CNTs, enables compressive strength prediction, and has high accuracy. Model validation is demonstrated by comparing experimental results of CNT-blended mixtures. The experimental results comprised comparisons of the compressive strength values of CNT-blended mixtures from 1-day to 1-year of age. The CNT-cement composite hydration analysis model demonstrates high accuracy in its predictions. Especially, long-term strength can be forecasted with an error margin of just 3%.