Performance-Based Design of Ferronickel Slag Alkali-Activated Concrete for High Thermal Load Applications

Area of Science:

• Materials Science
• Civil Engineering
• Sustainable Construction

Background:

• Ordinary Portland cement (OPC) concrete production has significant environmental impacts.
• Alkali-activated concrete (AAC) offers a sustainable alternative, but mix design standards are lacking, especially for ferronickel slag (FNS).
• High-temperature applications require concrete with enhanced thermal stability and mechanical integrity.

Purpose of the Study:

• To develop optimized alkali-activated concrete using ferronickel slag (FNS) for high-temperature applications.
• To minimize environmental impact while achieving high compressive strength and workability.
• To evaluate the performance of FNS-AAC after high-temperature exposure.

Main Methods:

• Response surface methodology (RSM) and mixture design of experiments were used to optimize FNS-AAC.
• Five components (water, FNS-based binder, three aggregate sizes) were optimized.
• Compressive strength and slump were tested before and after exposure to 600 °C.

Main Results:

• The optimal FNS-AAC mix achieved 88 MPa unheated and 34 MPa post-heating strength (140 mm slump).
• An upscaled mix showed improved workability (210 mm slump) but reduced post-heating strength (23.5 MPa).
• Replacing limestone with olivine aggregates improved post-heating strength (32 MPa).
• Life Cycle Analysis indicated 77% lower CO2 emissions compared to OPC concrete.

Conclusions:

• Mixture design of experiments is a viable performance-based methodology for FNS-AAC.
• The developed FNS-AAC is a promising, eco-friendly material for high-strength, high-temperature construction.
• This approach advances the application of AAC in construction where prescriptive standards are absent.