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Detecting the Water-soluble Chloride Distribution of Cement Paste in a High-precision Way
Published on: November 21, 2017
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Effective Medium Method for Chloride Diffusion Coefficient of Mature Fly Ash Cement Paste.
Hong Zhou1, Xin-Zhu Zhou2, Jian Zhang3
1Architectural Engineering School, Jinhua Polytechnic, Jinhua 321007, China. 20050267@jhc.edu.cn.
Materials (Basel, Switzerland)
|March 13, 2019
Summary
This study introduces an effective medium method (EMM) to evaluate the chloride diffusion coefficient in fly ash cement paste. Higher fly ash content and longer curing ages reduce chloride diffusion, enhancing concrete durability.
Area of Science:
- Civil Engineering
- Materials Science
- Chemical Engineering
Background:
- Concrete durability is crucial for structures in chloride environments.
- Chloride diffusion coefficient is a key parameter for durability assessment.
- Fly ash cement paste offers potential for improved concrete performance.
Purpose of the Study:
- To present an effective medium method (EMM) for evaluating the chloride diffusion coefficient of mature fly ash cement paste.
- To model fly ash cement paste as a two-phase composite material.
- To analytically derive the chloride diffusion coefficient using percolation theory.
Main Methods:
- Numerical estimation of cement and fly ash hydration degrees.
- Modeling fly ash cement paste as a solid phase and pore space composite.
- Modification of EMM with percolation theory for analytical derivation.
Main Results:
- A larger fly ash content and/or curing age reduces the chloride diffusion coefficient.
- The chloride diffusion coefficient decreases with a lower water/binder ratio.
- Experimental validation confirmed the EMM's accuracy up to 540 days.
Conclusions:
- The EMM effectively evaluates the chloride diffusion coefficient in fly ash cement paste.
- Fly ash content, curing age, and water/binder ratio significantly influence chloride diffusion.
- The developed method provides a reliable tool for concrete durability design.
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