Carbonated Slag Composite for Lower-CO2 Cement Replacement
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Solution Overview
Problem
The construction industry faces significant carbon dioxide emissions from Portland cement production, and there is a need for a method to reduce these emissions while maintaining concrete and mortar strength, utilizing waste materials, and reducing cement usage.
Innovation Solution
A method involving the production of a carbonated composite using metal slag, sodium gluconate, and carbon dioxide to form a supplementary cementitious material, which is then used to replace Portland cement in concrete and mortar production.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Portland cement is used to produce concrete and mortar, then strength is achieved, but carbon dioxide emissions increase
Solution Approach 1:
The invention captures carbon dioxide, a harmful greenhouse gas, and converts it into a beneficial product by reacting it with metal slag to form calcium carbonate in the carbonated composite. This process transforms CO2 from an emission problem into a valuable component that enhances the composite material's properties while reducing atmospheric carbon dioxide levels
Solution Approach 2:
The invention changes the chemical composition parameters of the composite material by incorporating carbonated metal slag with specific calcium carbonate content (30-70% by weight). This parameter change allows the material to achieve sufficient strength for concrete and mortar applications while reducing the required Portland cement content to 10-50% by weight, thereby reducing carbon dioxide emissions
2Object-generated harmful factors
If Portland cement usage is reduced, then carbon dioxide emissions decrease, but concrete and mortar strength may be compromised
Solution Approach 1:
The invention creates a composite material consisting of carbonated metal slag combined with Portland cement in optimized proportions (10-50% cement by weight). This composite leverages the reactive calcium carbonate in the carbonated slag to contribute to strength development while reducing the cement matrix requirement, achieving both environmental and mechanical performance goals
Solution Approach 2:
The carbonated metal slag acts as an intermediary material that bridges the gap between waste metal slag and functional cementitious material. The carbonation process transforms the slag into a material with pozzolanic and cementitious properties, enabling it to partially replace Portland cement while maintaining or enhancing concrete strength
3Loss of substance
If waste metal slag is reused, then environmental impact is reduced, but material quality and consistency may be compromised
Solution Approach 1:
The invention applies preliminary carbonation treatment to metal slag before using it in concrete applications. This pre-treatment process stabilizes the chemical composition by converting variable metal slag components into consistent calcium carbonate structures, ensuring reliable performance in the final composite material while enabling effective waste reuse
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
This method reduces carbon dioxide emissions by capturing carbon dioxide in the composite, enhances concrete and mortar strength, and allows for the reuse of waste materials, particularly metal slag, while minimizing Portland cement usage.
Implementation Method 1
treating the slurry with carbon dioxide, to form a wet solid residue
Data Source
AI summary
The present invention relates to a method of producing a carbonated composite:a. providing a particulate mineral material, wherein the mineral material comprises metal slag, wherein the metal slag comprises steel slag;b. providing a modifier, wherein the modifier comprises sodium gluconate;c. mixing the mineral material and the modifier with water to form a slurry;d. treating the slurry with carbon dioxide, to form a wet solid residue, wherein the concentration of carbon dioxide is greater than about 10 vol%; ande. drying the wet solid residue to form the carbonated composite.