Ultrasonic characterization and mechanical performance of self-compacting concrete in fresh and hardened states

This study provides a thorough evaluation of self-compacting concrete (SCC) properties in both its fresh and hardened states using advanced ultrasonic testing techniques. While existing research has offered valuable insights into SCC characteristics, a systematic analysis correlating ultrasonic parameters with both rheological and mechanical properties has been lacking. This research addresses this gap through extensive testing and analysis of critical parameters, including air content, water absorption, plastic viscosity, yield stress, density, compressive strength, and Young's modulus. Our findings reveal that ultrasonic velocity exhibits strong positive correlations with plastic viscosity (R² = 0.95), yield stress (R² = 0.97), and fresh density (R² = 0.99). Increased plastic viscosity and yield stress are associated with higher ultrasonic velocity, indicating enhanced internal consistency and material integrity. Similarly, fresh density positively correlates with ultrasonic velocity, reflecting improved compactness and uniformity. These relationships underscore the significance of these parameters in influencing SCC's ultrasonic characteristics. In the hardened state, ultrasonic velocity shows a robust positive correlation with compressive strength (R² = 0.98 to 0.99) and Young's modulus (R² = 0.96 to 0.98), suggesting that a denser and stiffer concrete matrix facilitates better ultrasonic wave transmission, indicative of superior structural integrity. These insights are instrumental for optimizing SCC mixture designs, enhancing both performance and durability in construction applications.