Self-Healing and Crack Recovery Position
1. Research axis definition
This axis positions Professor Bang Yeon Lee's lab in the research stream connecting ECC/SHCC crack-width control to autogenous healing, permeability recovery, mechanical reloading recovery, chloride resistance, and corrosion mitigation.
Core logic:
multiple microcracking
-> controlled crack width
-> water exposure and hydration/carbonation products
-> crack sealing and partial mechanical recovery
-> durability and service-life extension
2. Global literature anchor
Global anchor nodes:
- [[self_healing_ecc]]: book-level concept that ECC's tight crack width enhances self-healing.
- [[self_healing_mechanisms]]: hydration products, CaCO3, C-S-H/C-A-S-H, and crack blockage.
- [[crack_width_distribution]]: healing reliability depends on crack width.
- [[permeability]] and [[transport_properties]]: transport recovery is not identical to visual closure.
3. Lee lab representative papers
| Year | Paper | Positioning role | Source |
|---|---|---|---|
| 2018 | Self-healing properties of cement-based and alkali-activated slag-based fiber-reinforced composites | Cement vs AAS fiber-reinforced healing comparison | 00_sources/by_lee_lab_publications/source_notes/nguyen-2018-self-healing-properties-of-cement-based-and_source_note.md |
| 2019 | Effects of activator type on self-healing ability of AAS composites | Activator chemistry and early-age self-healing | 00_sources/by_lee_lab_publications/source_notes/nguyen-2019-effects-of-the-type-of_source_note.md |
| 2019 | Mechanical properties and self-healing capacity of eco-friendly ultra-high ductile slag-based composites | Links ultra-ductility and self-healing in slag-based composites | 00_sources/by_lee_lab_publications/source_notes/nguyen-2019-mechanical-properties-and-self-healing-capacity_source_note.md |
| 2020 | Autogenous healing of high strength ECC using calcium-containing binders | High-strength ECC healing via binder design | 00_sources/by_lee_lab_publications/source_notes/nguyen-2020-autogenous-healing-of-high-strength_source_note.md |
| 2021 | Effects of fiber hybridization on mechanical properties and autogenous healing of AAS composites | PE-PVA hybridization and healing threshold | 00_sources/by_lee_lab_publications/source_notes/choi-2021-effects-of-fiber-hybridization-on_source_note.md |
| 2023 | On crack healing in fiber-reinforced cementitious composites incorporating SHA and SAP | Modified permeability method and fiber-bridging-dominated healing | 00_sources/by_lee_lab_publications/source_notes/alemu-2023-on-crack-healing-in-fiber-reinforced_source_note.md |
| 2025 | Effect of self-healing of cracks in chloride ion diffusion and corrosion of ECC | Moves beyond water-tightness to chloride/corrosion performance | 00_sources/by_lee_lab_publications/source_notes/alemu-2025-effect-of-self-healing-of-cracks_source_note.md |
4. Key evidence and metrics
- Alemu et al. 2023: fiber bridging enables multi-cracked ECC to reach about 90% water permeability reduction even under high preloading strain conditions recorded in the source note.
- Alemu et al. 2023: reducing fiber content substantially reduces healed fraction, indicating fiber bridging is a primary healing enabler.
- Choi et al. 2021: PE-PVA hybrid AAS composites expanded complete healing threshold and showed tensile strength recovery in reloading tests.
- Alemu et al. 2025: water-tightness alone does not guarantee chloride resistance; crack-width threshold for chloride resistance is stricter than permeability closure.
- Nguyen et al. 2018/2019/2020: binder composition and activator type influence healing products and recovery.
5. What is distinctive about Lee lab contribution
The lab's self-healing contribution is distinctive because it treats healing as a crack-controlled durability function rather than only as a chemical-admixture effect. The research line compares binders, fibers, healing agents, permeability, reloading, chloride diffusion, and corrosion response.
6. Strategic novelty claims
- Lee lab positions self-healing ECC as a coupled problem of crack-width control, fiber bridging, and binder chemistry.
- The lab's work cautions that visual crack closure or water-tightness does not necessarily imply chloride impermeability.
- The lab connects self-healing to practical durability metrics: permeability, stiffness/tensile recovery, chloride diffusion, and corrosion current.
- Hybrid fiber and recycled fiber systems are evaluated not only for tensile ductility but also for healing and reloading performance.
7. Manuscript intro/discussion reusable paragraphs
Intro paragraph draft:
ECC self-healing is fundamentally enabled by distributed microcracking and controlled crack width. While supplementary healing agents can accelerate sealing, the Lee lab's studies show that fiber bridging, crack width, binder chemistry, and exposure conditions jointly govern recovery. Therefore, self-healing should be evaluated using transport and mechanical recovery metrics rather than visual closure alone.
Discussion paragraph draft:
The observed healing behavior is consistent with the Lee lab self-healing lineage, where crack-width control and fiber bridging provide the physical boundary conditions for healing products to form and block transport. The result also supports the caution that permeability recovery and chloride resistance should be distinguished when assessing durability.
8. Proposal background reusable paragraphs
Long-life infrastructure requires cementitious materials that can limit damage propagation and recover transport resistance after cracking. ECC provides an intrinsic platform for this because crack width is controlled by micromechanical design. The Lee lab's self-healing studies establish a source-grounded basis for connecting crack control, binder chemistry, and healing performance, motivating future research on predictive self-healing design.
9. Open research opportunities
- Unified healing metrics linking visual closure, permeability, chloride diffusion, and electrochemical response.
- Predictive models for healing threshold crack width by binder and fiber type.
- Self-healing in recycled selvage fiber ECC and low-fiber EGC.
- Field exposure studies under wet-dry, chloride, carbonation, and temperature cycles.
- AI-assisted mapping from mix design to healing probability.
10. Linked Atlas nodes and source files
- [[self_healing_ecc]] —
04_material_systems/self_healing_ecc.md - [[self_healing_mechanisms]] —
02_concepts/self_healing_mechanisms.md - [[crack_width_distribution]] —
05_experiments/crack_width_distribution.md - [[permeability]] —
02_concepts/permeability.md - [[transport_properties]] —
02_concepts/transport_properties.md - Lab claim matrix:
07_visualization/by_lee_lab_publications_claim_evidence_matrix.csv