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Molecular Simulation Study on Mechanical Properties of Microcapsule-Based Self-Healing Cementitious Materials
Xianfeng Wang1, Wei Xie1, Long-Yuan Li2
1Guangdong Provincial Key Laboratory of Durability for Marine Civil Engineering, College of Civil and Transportation Engineering, Shenzhen University, Shenzhen 518060, China.
Polymers
|February 15, 2022
Summary
Molecular dynamics simulations reveal that epoxy resin, particularly with TEPA curing, enhances self-healing concrete. This improves interfacial adhesion and ductility, crucial for repairing micro-cracks in concrete structures.
Area of Science:
- Materials Science
- Civil Engineering
- Nanotechnology
Background:
- Microcapsule-based self-healing concrete offers a promising solution for repairing micro-cracks.
- Understanding the microscopic interactions between healing agents and cementitious matrices is vital for optimizing performance.
- Epoxy resin is a key component in many self-healing concrete formulations.
Purpose of the Study:
- To investigate the microscopic mechanical and interfacial properties of epoxy resin within a cement matrix.
- To evaluate the influence of different curing agents on the epoxy resin/cement composite.
- To elucidate the role of epoxy resin in enhancing the self-healing capabilities of concrete.
Main Methods:
- Molecular dynamics simulations were employed to model the behavior of the composite material.
- Uniaxial tension was applied along the z-axis to simulate mechanical stress.
- Analysis included radial distribution function, interface binding energy, and hydrogen bonding.
Main Results:
- The epoxy resin/C-S-H (calcium-silicate-hydrate) composite exhibited maximum stress strength when tetraethylenepentamine (TEPA) was used as the curing agent.
- Interface binding energy between epoxy resin and the cement matrix increased with strain up to peak stress.
- Cured epoxy resin was found to significantly enhance interfacial adhesion and composite ductility.
Conclusions:
- Epoxy resin, especially when cured with TEPA, effectively improves the mechanical properties of self-healing concrete.
- Enhanced interfacial adhesion and ductility contribute to the material's ability to repair micro-cracks.
- These findings support the use of microcapsule-based self-healing cementitious materials for improved structural durability.
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