Optimization of Low-Density Hydroceramic Systems for Long-Term Stability at High Temperatures

Area of Science:

• Materials Science
• Ceramics Engineering
• Geochemistry

Background:

• Hydroceramic systems require optimization for high-temperature applications.
• Understanding the role of raw material composition is crucial for material performance.

Purpose of the Study:

• To optimize hydroceramic systems for high-temperature resistance and long-term stability.
• To investigate the influence of Ca/Si/Al ratios and additives like nano-activated alumina and silica fume.

Main Methods:

• Preparation of hydroceramic slurries with controlled density and setting time.
• High-temperature curing (240 °C, 50 MPa) for extended periods (2, 30, 90 days).
• Evaluation of compressive strength, water permeability, porosity (MIP), thermal stability (TGA), and phase composition (XRD).

Main Results:

• Nano-activated alumina improved macroscopic properties and promoted tobermorite 11 Å formation.
• Silica fume enhanced system properties and long-term stability by promoting silica sand reaction.
• Slurries with a Ca/Si ratio of 1 exhibited superior long-term stability compared to those with a Ca/Si ratio of 0.5.

Conclusions:

• Nano-activated alumina and silica fume are effective additives for enhancing hydroceramic systems.
• Optimized Ca/Si ratios and material compositions lead to superior high-temperature resistance and durability.
• The best-performing hydroceramic system maintained over 19 MPa compressive strength after 90 days at 240 °C.