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Curing Regime Optimization of Red Mud-Based Geopolymers.
Zhongping Yang1,2,3, Shuang Yang1, Xuyong Li1
1School of Civil Engineering, Chongqing University, Chongqing 400045, China.
Langmuir : the ACS Journal of Surfaces and Colloids
|April 28, 2025
Summary
Optimizing curing conditions for red mud geopolymer (RMG) is key. Elevated temperature and humidity up to 24 hours significantly enhance strength, with an optimal regime identified for superior mechanical performance.
Area of Science:
- Materials Science
- Geochemistry
- Civil Engineering
Background:
- Current red mud geopolymer (RMG) curing follows cement science, which is ill-suited due to different strength mechanisms.
- Geopolymerization requires high alkalinity, elevated temperatures, and humidity, unlike cement hydration.
Purpose of the Study:
- To investigate the impact of curing temperature, humidity, and duration on RMG mechanical properties.
- To determine the optimal curing regime for red mud-based geopolymer using response surface analysis.
Main Methods:
- Red mud-based geopolymer (RMG) specimens were subjected to varied curing regimes.
- Mechanical performance was assessed using Unconfined Compressive Strength (UCS).
- Microstructure, phase composition, and chemical structure were analyzed using MIP, SEM, XRD, and FTIR.
Main Results:
- Increased curing temperature (40-80°C) enhanced RMG strength, but excessive heat caused cracking.
- Moist curing (80% RH) improved UCS by 19.8% compared to 70% RH, mitigating cracks and pores.
- Strength increased with curing duration up to 24 hours, then decreased sharply at 48 hours due to pore generation.
Conclusions:
- Curing temperature, humidity, and duration significantly influence RMG mechanical performance.
- An optimal curing regime of 21.5 h at 73.8°C and 78.9% RH was identified.
- Understanding these parameters is crucial for developing effective red mud-based geopolymer applications.
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