New cold-bonded artificial aggregate using a Ba(OH)2-activated cementless binder for cement-free concrete production

This study introduces cold-bonded cementless artificial aggregates using a Ba(OH)2-activated GGBFS binder system through a pelletization technique to produce complete cement-free concrete as an engineering application. The developed aggregate offers mechanical properties, achieving 10.8 MPa bulk crushing strength at 28 days and satisfying the requirements of lightweight aggregates according to EN 13055. Additionally, it complies with TCLP regulations, demonstrating excellent leaching resistance. The complete cement-free concrete was produced using the developed aggregate, demonstrating promising mechanical properties, exceeding 64.5 MPa compressive strength and 35.5 GPa elastic modulus, greater than previous studies. Economic analysis revealed a production cost of approximately USD 60.85/ton. Regression analysis identified a strong correlation (R2 = 0.9979) between disk revolving speed and diameter, enabling efficient production scaling across different scales (lab-scale, semi-pilot, and pilot). This research paves the way for a sustainable, cement-free, and natural aggregate-free concrete, achieved through the introduction of an eco-friendly, high-performance cold-bonded artificial aggregate and cementless binder that preserves mechanical integrity while delivering significant sustainability values.