Choi et al. (2021) — Hybrid PE-PVA Fiber Reinforcement and Self-Healing in Slag Composites
Citation
Jeong-Il Choi, Huy Hoàng Nguyễn, Se-Eon Park, Ravi Ranade, Bang Yeon Lee (2021). Effects of fiber hybridization on mechanical properties and autogenous healing of alkali-activated slag-based composites. Construction and Building Materials, 310, 125280.
- DOI:
10.1016/j.conbuildmat.2021.125280 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 8: Self-Healing and Durability (also Chapter 4)
- Source PDF:
primary_data/choi-2021-effects-of-fiber-hybridization-on.pdfIJP06221E_Effects of fiber hybridization_CBM.pdf` - Extracted text:
secondary_data/full_texts/choi-2021-effects-of-fiber-hybridization-on_full_text.mdsecondary_data/full_texts/IJP06221E_Effects of fiber hybridization_CBM_full_text.md` - Source note:
secondary_data/source_notes/choi-2021-effects-of-fiber-hybridization-on_source_note.mdsecondary_data/source_notes/IJP06221E_Effects of fiber hybridization_CBM_source_note.md`
Why this paper matters
Combines hydrophobic PE fibers (1.50 vol. %) with hydrophilic PVA fibers (0.25 vol. %) in 10 wt. % $\text{Ca(OH)}_2$-activated slag composites ($w/b = 0.30$), achieving superior initial tensile ductility (7.82 %) and maximizing 28-day underwater autogenous self-healing after 3.0 % pre-tensile strain. PVA fibers act as chemical nucleation substrates, expanding the complete healing threshold to $42.1\ \mu\text{m}$, enhancing resonant frequency recovery, and restoring post-healing tensile strength to 8.51 MPa (106.6 % recovery).
Main contribution
- PE-PVA Hybrid Synergistic Ductility: Proved that adding 0.25 vol. % PVA to 1.50 vol. % PE (E1.5-V0.25) elevated tensile strain capacity to $7.82\text{ \%}$ (vs $7.34\text{ \%}$ in mono-PE) while maintaining compressive strength at $38.3\text{ MPa}$.
- Expanded Self-Healing Window: Demonstrated complete crack closure up to $42.1\ \mu\text{m}$ in E1.5-V0.25 (vs $33.3\ \mu\text{m}$ for mono-PE) and achieved highest resonant frequency recovery rate ($RF_r = +3.3\text{ \%p}$).
- Mechanical Tensile Restoration: Following 28-day water healing after 3.0 % tensile damage, E1.5-V0.25 exceeded its virgin tensile strength, achieving $f_{ts-h} = 8.51\text{ MPa}$ (106.6 % recovery) and cumulative strain $\epsilon_h = 8.27\text{ \%}$, with new microcracks forming in virgin matrix during reloading.
Evidence summary
- Initial Direct Tensile Response (28d):
E1.5-V0.25(Hybrid): $\epsilon_u = 7.82\text{ \%}$, $\sigma_{tu} = 7.98\text{ MPa}$, $\sigma_{fc} = 3.05\text{ MPa}$, $f_c = 38.3\text{ MPa}$, SPI = 2.62 (Table 3, Figs. 3–5, Pages 3–5).E1.75-V0: $\epsilon_u = 7.77\text{ \%}$, $\sigma_{tu} = 9.06\text{ MPa}$, $\sigma_{fc} = 3.20\text{ MPa}$, $f_c = 38.2\text{ MPa}$, SPI = 2.83.E1.5-V0: $\epsilon_u = 7.34\text{ \%}$, $\sigma_{tu} = 7.87\text{ MPa}$, $\sigma_{fc} = 2.89\text{ MPa}$, $f_c = 38.4\text{ MPa}$, SPI = 2.72.- Autogenous Crack Healing (3.0 % pre-strain):
- Complete closure threshold: $42.1\ \mu\text{m}$ (E1.5-V0.25) vs $33.3\ \mu\text{m}$ (E1.5-V0) (Figs. 8–10, Pages 6–8).
- RF Recovery Rate: E1.5-V0.25 showed 3.3 %p higher recovery than E1.5-V0 (Fig. 12, Page 8).
- Reloading Tensile Recovery (28d healing):
E1.5-V0.25: $f_{ts-h} = 8.51 \pm 0.87\text{ MPa}$ (106.6 % recovery), $\epsilon_h = 8.27\text{ \%}$ (Table 5 & Fig. 15, Pages 8–10).E1.75-V0: $f_{ts-h} = 10.19 \pm 0.57\text{ MPa}$ (112.5 % recovery), $\epsilon_h = 7.98\text{ \%}$.E1.5-V0: $f_{ts-h} = 5.96\text{ MPa}$ (75.7 % recovery).- Healing Products: SEM/EDS confirmed dense $\text{CaCO}_3$ crystal filling with $\text{Ca/Si}$ atomic ratios of 256 to 2536 in E1.5-V0.25 (Table 6 & Fig. 18, Pages 9–12).
Linked Atlas nodes
04_material_systems/self_healing_ecc.md04_material_systems/green_ecc.md02_concepts/interface_properties.md05_experiments/crack_width_distribution.md05_experiments/direct_tensile_test.md
Relationship to Victor Li book
- Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
- Directly extends Chapter 8 (Self-Healing ECC) and Chapter 4 (co-authored with Ravi Ranade) by proving that a hybrid PE/PVA fiber system in cementless slag ECC resolves the conflict between ultra-high ductility and chemical healing nucleation, restoring 106.6 % of virgin tensile strength after 3.0 % tensile strain.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/self_healing_ecc.md |
Hybridizing 1.5 % PE with 0.25 % PVA fibers expands the complete autogenous crack healing threshold to 42.1 $\mu\text{m}$ after 3.0 % pre-tensile strain | Digital microscopy tracked complete crack closure up to $42.1\ \mu\text{m}$ in E1.5-V0.25 | Page 125280:7 & 10 / Figs. 8, 9, 10 | verified_from_pdf |
04_material_systems/self_healing_ecc.md |
Post-healing reloading verifies 106.6 % tensile strength recovery (8.51 MPa) and 8.27 % cumulative ductility in hybrid PE-PVA slag composite | Reloading tests recorded $f_{ts-h} = 8.51\text{ MPa}$ (106.6%) and cumulative ductility 8.27% | Page 125280:8 & 10 / Table 5 / Figs. 13, 15 | verified_from_pdf |
04_material_systems/green_ecc.md |
Adding 0.25 vol. % PVA fibers to 1.5 vol. % PE fibers enhances direct tensile strain capacity to 7.82 % with 38.3 MPa compressive strength | Direct tension tests verified $\epsilon_u = 7.82\text{ \%}$, $\sigma_{tu} = 7.98\text{ MPa}$, and $f_c = 38.3\text{ MPa}$ | Page 125280:1 & 5 / Table 3 / Figs. 3, 4, 5 | verified_from_pdf |
Verification status
- PDF preserved: yes (in
primary_data/IJP06221E_Effects of fiber hybridization_CBM.pdf) - Text extracted: yes (PyMuPDF, 13 pages)
- DOI verified: yes (
10.1016/j.conbuildmat.2021.125280) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- 1.50 % PE mono-fiber composite recovers only 75.7 % of virgin tensile strength upon reloading (5.96 MPa), proving that $V_f \ge 1.75\text{ vol. \%}$ or PVA hybridization is required for complete strength restoration.