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Optimizing Potassium-Based Activator Formulation for Balanced Reactivity, Flowability, Setting Time and Mechanical
Gulsen Nazerian1, Jun Gu1, Tine Tysmans2
1Sustainable Materials Engineering (SUME) Research Group, Department of Materials and Chemistry (MACH), Vrije Universiteit Brussel (VUB), Pleinlaan 2, 1050 Brussels, Belgium.
Materials (Basel, Switzerland)
|June 26, 2026
Summary
The potassium silicate modulus impacts alkali-activated slag paste properties. Higher moduli delay setting and reduce flowability, crucial for textile-reinforced concrete applications.
Area of Science:
- Materials Science
- Civil Engineering
- Sustainable Construction
Background:
- Alkali-activated materials (AAMs) offer sustainable alternatives to Ordinary Portland Cement (OPC).
- Ground granulated blast furnace slag (GGBFS) is a key precursor for AAMs.
- Alkaline activator chemistry significantly influences AAM performance.
Purpose of the Study:
- Investigate the effect of potassium silicate modulus (Ms) on GGBFS-based AAMs.
- Determine how Ms influences reactivity, setting time, flowability, and mechanical properties.
- Assess suitability for textile-reinforced cement/concrete (TRC) applications.
Main Methods:
- Prepared alkali-activated slag pastes using GGBFS and potassium silicate activators.
- Varied potassium silicate modulus (Ms) from 1.0 to 2.5.
- Cured specimens at 20 °C and 75% relative humidity for testing.
Main Results:
- Increasing Ms delayed reactivity and prolonged setting time.
- Higher Ms values decreased the flowability of fresh pastes.
- Flowability remained adequate for TRC applications.
- No consistent trends were observed in mechanical properties (elastic modulus, flexural, and compressive strength).
Conclusions:
- Potassium silicate modulus is a critical parameter for controlling fresh properties of alkali-activated slag pastes.
- Ms influences setting behavior and workability, with implications for TRC.
- Further research may be needed to optimize mechanical properties based on Ms.
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