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The Effects of Curing Temperature on CH-Based Fly Ash Composites
Xiangnan Ji1, Koji Takasu1, Hiroki Suyama1
1Department of Architecture, Faculty of Environmental Engineering, The University of Kitakyushu, Kitakyushu 808-0135, Japan.
Materials (Basel, Switzerland)
|April 13, 2023
Summary
Low-temperature curing enhances the performance of calcium hydroxide (CH)-based fly ash composites. High-temperature curing initially boosts strength but ultimately reduces CH and C-S-H content, leading to decreased compressive strength.
Area of Science:
- Materials Science
- Civil Engineering
- Geochemistry
Background:
- Curing temperature significantly influences cement paste compressive strength through the pozzolanic reaction.
- Variations in environmental conditions lead to diverse initial curing temperatures, an under-researched area.
- Understanding the impact of curing temperature on calcium hydroxide (CH)-based fly ash composites is crucial.
Purpose of the Study:
- To investigate the effect of curing temperature on the compressive strength of CH-based fly ash composites.
- To analyze the influence of curing temperature on reaction rate, CH content, and C-S-H gel formation.
- To establish the correlation between reaction rate and C-S-H content under different curing conditions.
Main Methods:
- CH-based composites were prepared using fly ashes from various carbon sources.
- Compressive strength, reaction kinetics, CH content, and C-S-H generation were quantified.
- Comparative analysis of low-temperature versus high-temperature curing effects was performed.
Main Results:
- High-temperature curing initially accelerated the CH-based reaction rate, reaching up to 28.29%.
- However, high-temperature curing resulted in a significant decrease in CH content (average 38% reduction) and C-S-H gel.
- Low-temperature curing yielded superior long-term performance and higher compressive strength in the composites.
Conclusions:
- Initial high-temperature curing enhances early compressive strength by accelerating the reaction rate.
- Sustained high-temperature curing negatively impacts CH and C-S-H content, reducing overall compressive strength.
- Low-temperature curing is recommended for optimal performance of CH-based fly ash composites.
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