Slag Binder Accelerator Using Nucleating Agents
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Solution Overview
Problem
Existing hydraulic binders based on calcium aluminosilicate derivatives, such as those using blast furnace slag, face challenges with slow hydration and setting times, especially at low temperatures, which affects their reactivity and carbon footprint reduction in cement production.
Innovation Solution
A hydraulic binder comprising at least 80% ground granulated blast furnace slag, combined with a hardening reaction accelerator that includes a source of calcium sulfate and nucleating agents with a high BET specific surface area and fine particle size, such as calcium carbonates or silicate hydrates, to enhance hydration and setting performance without toxic additives.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If ground granulated blast furnace slag is used as the primary binder component, then carbon dioxide emissions are reduced and reactivity is improved, but hydration rate becomes too slow especially at low temperatures
Solution Approach 1:
The patent introduces an intermediary activation system consisting of calcium sulfate and nucleating agents that mediates between the low-reactivity slag and water, facilitating faster hydration without requiring highly alkaline activators. This intermediary system provides the necessary nuclei for crystal formation and maintains appropriate saturation levels to accelerate slag hydration.
Solution Approach 2:
The patent changes physical parameters of the activation system by using nucleating agents with specific surface area greater than 1 m²/g and controlled particle size distribution (50% of particles less than 5 μm). It also optimizes the calcium sulfate content (1-10% by weight) to achieve the right saturation level for accelerated hydration at low temperatures.
2Object-generated harmful factors
If ground granulated blast furnace slag is used as the primary binder component, then carbon footprint is reduced, but setting and hardening times become too short due to slow hydration
Solution Approach 1:
The activation system acts as an intermediary that bridges the gap between environmental sustainability and construction timeline requirements, enabling slag-based binders to achieve practical setting times while maintaining low carbon footprint.
Solution Approach 2:
By controlling particle size distribution and specific surface area of nucleating agents, the patent optimizes the kinetics of hydration to achieve appropriate setting and hardening times suitable for construction applications.
3Productivity
If highly alkaline activator systems are used to accelerate slag hydration, then hydration rate is improved, but safety deteriorates due to corrosive and irritant properties
Solution Approach 1:
The patent replaces highly alkaline activators with a safer intermediary system based on calcium sulfate and nucleating agents, which achieves similar hydration acceleration without the corrosive and irritant properties of strong alkalis.
Solution Approach 2:
The activation system uses inexpensive, non-hazardous materials (calcium sulfate and natural nucleating agents) that can be easily handled and applied, replacing expensive and dangerous alkaline activators.
4Loss of time
If existing activation systems with crushed limestone are used, then setting acceleration is achieved, but activation is insufficient when the essential binder constituent is calcium aluminosilicate derivative
Solution Approach 1:
The patent changes the fundamental parameters of the activation system by introducing nucleating agents with specific surface area greater than 1 m²/g and optimized particle size distribution, along with controlled calcium sulfate content, to achieve sufficient activation of calcium aluminosilicate derivatives.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
The solution accelerates the hydration of the binder at low temperatures, ensuring rapid mechanical performance and reducing the carbon footprint, while maintaining safety by avoiding irritant or corrosive substances, thus meeting stringent mechanical performance standards.
Implementation Method 1
at least one nucleating agent in the form of particles having a specific surface area BET greater than 1m2/g and having a size such that 50% of the particles have an average diameter less than 5 μm
Implementation Method 2
at least one source of calcium sulfate and at least one nucleating agent
Implementation Method 3
hydraulic binder comprising primarily a calcium aluminosilicate derivative and at least one accelerator of the binder's hardening reaction
Data Source
AI summary
The present invention relates to a hydraulic binder comprising at least 80% by weight of ground granulated blast furnace slag and at least one accelerator of the hardening reaction, said accelerator comprising at least one source of calcium sulfate and at least one nucleating agent in the form of particles having a specific surface area (BET) greater than 1 m²/g and a size such that 50% of the particles have an average diameter of less than 5 µm, said particles being selected from calcium carbonates, magnesium carbonates, calcium and magnesium carbonates, calcium silicate hydrates, and aluminum silicate hydrates, alone or in mixtures. This binder can be used in a mortar and concrete composition which, when mixed with water, yields construction materials.