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Biomass ash as supplementary cementitious material: microstructural mechanism underlying cement paste strength
Shaoqiang Guo1, Huimei Zhang2,3, Chao Yuan4
1College of Architecture and Civil Engineering, Xi'an University of Science and Technology, Xi'an, 710054, China.
Scientific Reports
|July 1, 2026
Summary
Biomass ash (BA) as a supplementary cementitious material enhances cement paste strength up to 20% replacement. This silica-rich admixture improves C-S-H gel structure and pozzolanic reactivity, boosting mechanical properties.
Area of Science:
- Materials Science
- Civil Engineering
- Sustainable Construction
Background:
- Effective utilization of biomass ash (BA) is crucial for sustainable construction.
- BA can serve as a supplementary cementitious material (SCM) in cementitious applications.
- Understanding BA's influence on cement paste properties is essential for its practical application.
Purpose of the Study:
- To investigate the impact of BA as an SCM on cement paste properties.
- To analyze the mechanism of BA's effect on mechanical strength using microscopic techniques.
- To determine optimal BA replacement levels for enhanced cement paste performance.
Main Methods:
- Cement paste specimens prepared with BA replacement levels from 0% to 50%.
- Macroscopic tests evaluated fresh paste fluidity and compressive strength development.
- Microscopic characterization techniques analyzed the hydration mechanisms and microstructure.
Main Results:
- Fluidity slightly decreased with increasing BA content.
- Optimal performance observed at 20% BA replacement, with a 29.6% increase in 28-day compressive strength.
- BA exhibited significant pozzolanic reactivity, enhancing C-S-H gel structure and silicate polymerization.
Conclusions:
- Biomass ash is a viable supplementary cementitious material for improving cement paste properties.
- BA incorporation refines pore structure and enhances mechanical strength through pozzolanic reactions.
- A 20% replacement level offers the best balance of properties, with significant strength gains maintained up to 30% replacement.
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