Ductile Cast Cementitious Structure for CO2 Sequestration
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Solution Overview
Problem
Traditional concrete manufacturing is energy and resource-intensive, generates significant carbon emissions, and lacks durability due to brittleness and susceptibility to cracking, necessitating steel reinforcement, which is prone to corrosion.
Innovation Solution
A method involving controlled humidity conditioning and dehydration of a cementitious composite material to form a ductile cementitious structure capable of sequestering carbon dioxide, eliminating the need for steel reinforcement by enhancing material ductility and durability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If Portland cement is used as the binder in concrete, then the concrete achieves high compressive strength and binding properties, but it generates significant carbon dioxide emissions and consumes large amounts of energy during manufacturing
Solution Approach 1:
The patent changes the chemical composition parameters of the binder by replacing Portland cement with a blend of limestone and alternative cementitious materials. This parameter change maintains the binding properties and compressive strength while significantly reducing carbon dioxide emissions from the manufacturing process.
Solution Approach 2:
The patent uses a composite binder system combining limestone with alternative cementitious materials such as fly ash, slag, or other supplementary cementitious materials. This composite approach achieves the required mechanical strength while lowering the carbon footprint compared to pure Portland cement.
2Strength
If traditional concrete formulation is used, then the concrete achieves high compressive strength, but it exhibits brittleness and poor durability due to susceptibility to cracking under tensile loads
Solution Approach 1:
The patent modifies the mechanical properties of concrete by changing the binder composition and optimizing the water-to-binder ratio. These parameter changes result in a more ductile material that can withstand tensile stresses and resist cracking, thereby improving durability while maintaining compressive strength.
Solution Approach 2:
The use of a composite binder system with alternative cementitious materials creates a more flexible and durable concrete matrix. This composite material approach enhances the concrete's ability to deform without cracking, improving its reliability under various loading conditions.
3Strength
If steel reinforcement is added to concrete to improve tensile strength, then the concrete can resist bending moments and shear forces, but the reinforcement is prone to corrosion when cracks occur
Solution Approach 1:
The patent extracts or eliminates the steel reinforcement component from the concrete structure by developing a ductile concrete formulation that inherently resists cracking. This removes the source of corrosion problems associated with reinforced concrete while maintaining the necessary tensile strength through material ductility.
Solution Approach 2:
The ductile concrete formulation provides self-service by inherently resisting cracks through its material properties, eliminating the need for external protection systems for reinforcement. The concrete itself serves to prevent the crack formation that would otherwise lead to reinforcement corrosion.
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 method achieves high carbon dioxide uptake and tensile strain capacity, reducing energy consumption and emissions while providing durable, crack-resistant concrete structures with enhanced tensile strength and self-healing properties.
Implementation Method 1
The cast cementitious structure is capable of a carbon dioxide (CO2) uptake level of greater than or equal to about 6% by weight of the binder
Implementation Method 2
The cementitious composite material is dried to remove greater than or equal to about 10% by weight of initial water in the cementitious composite material
Data Source
AI summary
Methods of preparing a cementitious structure for carbon dioxide (CO2) sequestration are provided. The cementitious structure may be a cast in a mold. First, a cementitious composite material comprising binder and water is conditioned, for example, in a mold by exposing the cementitious composite material to ≥about 50% to ≤about 80% relative humidity for ≥about 3 hours to ≤about 24 hours. The cementitious composite material is then dried to remove ≥about 10% by weight of initial water in the cementitious composite material. The cementitious structure formed is capable of a carbon dioxide uptake level of greater than or equal to about 6% by weight binder. The cementitious structure has a tensile strain capacity of ≥about 1% and a uniaxial tensile strength of ≥about 1 MPa. The method may also include carbonating the cementitious structure, following by an optional further hydration process.