Predicting the Elastic Modulus of Recycled Concrete Considering Material Nonuniformity: Mesoscale Numerical Method

Area of Science:

• Civil Engineering
• Materials Science
• Structural Engineering

Background:

• Evaluating the elastic modulus of recycled concrete is crucial for structural stability and resource utilization.
• Existing theoretical and experimental methods have limitations in cost and precision.
• Understanding the influence of constituent materials and microstructural features is essential.

Purpose of the Study:

• To propose a novel, low-cost, and high-precision mesoscale model for predicting the elastic modulus of recycled concrete.
• To investigate the impact of coarse aggregate, contact surface, gelling material, and air bubbles on the elastic modulus.
• To validate the proposed model against experimental results.

Main Methods:

• Development of the mesoscale Integrated Reconstruction and Simulation Method (IRSM) model.
• The IRSM model incorporates Identification, Reconstruction, Simulation, and Monte Carlo processes.
• Parametric analysis using Pearson's Coefficients to determine factor influence on elastic modulus.

Main Results:

• The IRSM model accurately reconstructs geometric characteristics and accumulation of coarse aggregate.
• Model predictions show less than 5% error compared to experimental results, validating its rationality.
• Key factors influencing elastic modulus, in descending order, are: cement elastic modulus, coarse aggregate elastic modulus, coarse aggregate content, air void content, contact surface elastic modulus, and contact surface thickness.

Conclusions:

• The proposed IRSM model provides a reliable and efficient tool for predicting the elastic modulus of recycled concrete.
• Air void content and contact surface thickness negatively impact the elastic modulus.
• Factors influence concrete's deformation resistance primarily through 'force chain' adjustments, affecting force transfer, path numbers, and integrity.