Performance Characterization and Composition Design Using Machine Learning and Optimal Technology for...

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Construction

Background:

• Fly ash-slag-based alkali-activated materials offer superior mechanical properties and a reduced carbon footprint compared to Portland cement.
• Replacing Portland cement with slag-desulfurization gypsum-based alkali-activated materials promotes waste utilization and environmental protection.
• Effective performance characterization and compositional design are crucial for the engineering application of these advanced materials.

Purpose of the Study:

• To develop a novel framework for performance characterization and composition design of slag-desulfurization gypsum-based alkali-activated materials.
• To optimize the material composition for maximum flexural and compressive strength at early ages (1, 3, and 7 days).
• To validate the framework's effectiveness through laboratory testing and comparison with traditional methods.

Main Methods:

• A hybrid framework combining Categorical Gradient Boosting (CatBoost) for characterization and simplicial homology global optimization (SHGO) for design.
• Utilized SHapley Additive exPlanations (SHAPs) and partial dependence plots (PDP) to evaluate the CatBoost model.
• Conducted laboratory tests to verify the predicted optimal composition and performance.

Main Results:

• The optimal composition for maximizing early-age strength was determined as Ca(OH)2: 3.1%, fly ash: 2.6%, DG: 0.53%, alkali: 4.3%, modulus: 1.18, and W/G: 0.49.
• The optimized material exhibited significant increases in flexural and compressive strength (up to 41.89%) compared to traditionally formulated materials.
• Laboratory results closely matched the framework's predictions, confirming the accuracy of the CatBoost characterization model.

Conclusions:

• The developed framework provides a scientific and efficient approach for characterizing the performance of alkali-activated materials.
• This methodology enables precise compositional design to achieve desired mechanical properties.
• The study demonstrates a viable pathway for developing sustainable, high-performance construction materials as alternatives to Portland cement.