Cement Admixture Copolymer Layered Double Hydroxide Corrosion
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Solution Overview
Problem
Conventional cement admixtures, particularly polycarboxylic acid (PCA)-based admixtures, face challenges in maintaining both dispersibility and workability over time, and they lack sufficient corrosion resistance, especially in marine concrete structures where chloride ions can cause corrosion.
Innovation Solution
A cement admixture is developed using a polycarboxylic acid-based copolymer derived from a macromonomer and a layered double hydroxide, which is prepared by reacting a compound with a saturated or unsaturated dicarboxylic acid, an anhydride, or their mixture, under specific conditions to enhance dispersibility and workability while providing corrosion resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of stationary object
If the molecular structure of PCA-based admixture is modified to improve workability maintenance, then workability maintenance is improved, but dispersibility is considerably reduced
Solution Approach 1:
The patent combines polycarboxylic acid-based copolymer with layered double hydroxide to create a composite cement admixture. The copolymer provides dispersibility through steric hindrance repulsion from polyethylene oxide side chains, while the layered double hydroxide structure enhances workability maintenance. This composite approach allows both dispersibility and workability maintenance to be improved simultaneously rather than requiring a trade-off between them.
2Manufacturing precision
If dispersibility of PCA-based admixture is improved, then dispersibility is improved, but workability maintenance is considerably reduced
Solution Approach 1:
The patent creates a composite system where polycarboxylic acid-based copolymer provides strong dispersibility through its three-dimensional molecular structure and steric hindrance repulsion, while layered double hydroxide contributes to sustained workability maintenance. The synergistic interaction between these two components resolves the trade-off, allowing high dispersibility to be achieved without sacrificing workability maintenance.
3Reliability
If conventional PCA-based admixtures are used to reduce chloride ion infiltration, then corrosion resistance is improved, but dispersibility and workability maintenance become insufficient
Solution Approach 1:
The patent develops a composite cement admixture combining polycarboxylic acid-based copolymer with layered double hydroxide. The copolymer component ensures excellent dispersibility and workability maintenance, while the layered double hydroxide provides enhanced corrosion resistance by forming a protective barrier that reduces chloride ion infiltration. This composite structure achieves all three performance requirements simultaneously.
Solution Approach 2:
The patent applies different functional components to different aspects of concrete performance: the polycarboxylic acid-based copolymer is optimized for dispersibility and workability maintenance, while the layered double hydroxide is specifically designed to provide corrosion resistance. Each component performs its specialized function locally, and their combination achieves comprehensive performance improvement.
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 resulting cement admixture exhibits improved dispersibility, workability maintenance, and corrosion resistance, with a simplified and cost-effective manufacturing process, effectively addressing the trade-off issues of conventional PCA-based admixtures.
Implementation Method 1
The PCA-based admixtures may form a three-dimensional molecular structure due to a polyethylene oxide side chain contained in the polymer strucure, and steric hindrance repulsion caused thereby disperses cement particles, thereby fluidizing a cement composition.
Implementation Method 2
with the construction of marine concrete structures and use of washed sand, chloride ions infiltrate into the concrete structures, thereby causing corrosion in the concrete structures
Data Source
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AI summary
Disclosed are a macromonomer for preparing a cement admixture and a method of preparing the same; a cement admixture comprising a polycarboxylic acid-based copolymer derived from the macromonomer and a layered double hydroxide; and a method of preparing the same. The polycarboxylic acid-based copolymer comprises (a) a structural unit derived from a macromonomer compound represented by Formula 1 below and (b) a structural unit derived from an acrylic monomer represented by Formula 4. The cement admixture has superior dispersibility, workability maintenance, and corrosion resistance. [Formula 1]: CH2=CR1-(CH2)m-O-(CH2CH2O)n-OCO-R2-COOH [Formula 4]: CH2=CR3-COM1