Lime Cementitious Compositions for Faster CO2 Concrete Curing
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Solution Overview
Problem
Existing concrete curing methods do not effectively utilize carbon dioxide for carbonation, limiting the efficiency and speed of the carbonation process.
Innovation Solution
Incorporating lime into cementitious compositions that react with carbon dioxide to produce calcium carbonate, enhancing the carbon dioxide uptake and sequestration during the mixing and curing of concrete.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If traditional hydration curing is used, then the curing process is simple and well-understood, but the curing time is long and carbon dioxide uptake is limited
Solution Approach 1:
The patent changes the chemical parameters of the curing environment by introducing carbon dioxide gas and adjusting its concentration (e.g., 10-100% CO2 atmosphere). This parameter change accelerates the carbonation reaction rate, enabling faster curing compared to traditional hydration curing while maintaining structural integrity.
Solution Approach 2:
The patent creates a composite curing approach by combining carbonation curing with traditional hydration curing. The cementitious composition contains both calcium hydroxide (for carbonation) and calcium silicate hydrate (for hydration), allowing simultaneous operation of two curing mechanisms to achieve both speed and strength.
2Quantity of substance
If carbonation curing is implemented, then carbon dioxide uptake increases, but the process efficiency and sequestration rate remain suboptimal
Solution Approach 1:
The patent incorporates lime (calcium oxide) and calcium hydroxide into the cementitious composition before curing. These pre-positioned reactants are ready to immediately react with carbon dioxide upon exposure, eliminating the need to wait for slow in-situ formation of calcium hydroxide during hydration. This preliminary preparation significantly accelerates the carbonation sequestration rate.
Solution Approach 2:
The patent creates localized zones of high reactivity within the cementitious composition by distributing lime and calcium hydroxide throughout the matrix. This ensures that carbon dioxide reacts efficiently at multiple locations simultaneously, maximizing overall uptake capacity and sequestration rate rather than relying on surface-only carbonation.
3Quantity of substance
If more reactants are added to increase carbon dioxide reaction capacity, then the weight percent of reactants increases, but the composition complexity and formulation difficulty increase
Solution Approach 1:
The patent uses lime (calcium oxide) which serves multiple functions: it reacts with water to form calcium hydroxide (increasing reactant content for CO2 uptake), it contributes to the overall cementitious matrix strength, and it maintains workability of the fresh mixture. This multi-functionality allows high reactant content without proportionally increasing formulation complexity.
Solution Approach 2:
The patent combines lime and calcium hydroxide in the same cementitious composition, where lime acts as a precursor that converts to calcium hydroxide in situ. This merging approach maximizes the total calcium-containing reactant content available for carbonation while using a single additive (lime) rather than requiring separate formulations for each reactant.
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 inclusion of lime increases the weight percent of reactants that react with carbon dioxide, thereby increasing the uptake and sequestration of carbon dioxide, leading to more efficient and faster concrete curing.
Implementation Method 1
Incorporating lime into cementitious compositions that react with carbon dioxide to produce calcium carbonate
Implementation Method 2
along with a gas-entrained admixture containing carbon dioxide, to enhance carbon dioxide uptake and sequestration during the concrete curing process
Data Source
AI summary
Cementitious compositions comprising lime, which may be foamed or non-foamed compositions, may increase carbon dioxide uptake of the cementitious compositions. Said cementitious compositions may be used in various cementing methods including pre-casting methods, cast-in-place methods, and primary or secondary cementing operations in a wellbore. The carbon dioxide may be added to the cementitious compositions during mixing, during pre-conditioning, during curing, or any combination thereof. Further, the carbon dioxide may be delivered as a gas (e.g., a gas that includes 1 vol % to 100 vol % carbon dioxide) or as a gas-entrained admixture that includes the gas, water, and a foaming agent.