Hwang et al. (2025) — Micromechanical Role of Selvage Fibers in Engineered Cementitious Composites

Citation

Eunyoung Hwang, Se-Eon Park, Youngsang Kim, Huy Hoàng Nguyễn, Bang Yeon Lee (2025). From textile waste to high-performance composites: investigating the role of selvage fibers in engineered cementitious composites. Journal of Building Engineering, 108, 112964.

• DOI: 10.1016/j.jobe.2025.112964
• Atlas layer: supporting
• Related Victor Li book chapter: Chapter 4: Micromechanics-Based Material Design & Chapter 5: Multiple Cracking Criteria
• Source PDF: primary_data/hwang-2025-from-textile-waste-to-high-performance.pdfIJP08525E_From textile waste_JBE.pdf`
• Extracted text: secondary_data/full_texts/hwang-2025-from-textile-waste-to-high-performance_full_text.mdsecondary_data/full_texts/IJP08525E_From textile waste_JBE_full_text.md`
• Source note: secondary_data/source_notes/hwang-2025-from-textile-waste-to-high-performance_source_note.mdsecondary_data/source_notes/IJP08525E_From textile waste_JBE_source_note.md`

Why this paper matters

Provides a complete micromechanical deconstruction and theoretical validation of upcycled textile selvage fibers (SE-15: 81 vol. % PE, 7 vol. % GF, 12 vol. % PET) vs isolated constituent single fibers (PE-15, GF-15, PET-15). Links single-fiber pullout interfacial parameters ($\tau_0 = 1.45\text{ MPa}$ for PE) and matrix fracture toughness ($K_m = 0.65\text{ MPa}\cdot\text{m}^{1/2}, J_{tip} = 39.9\text{ J/m}^2$) directly to composite fiber bridging curves ($\sigma_B(\delta)$), proving that SE-15 satisfies both Kanda-Li PSH design criteria ($SPI = 2.26 > 1.3, EPI = 3.40 > 2.7$) to achieve $63.2\text{ MPa}$ compressive strength, $8.01\text{ MPa}$ tensile strength, and $5.25 \pm 0.71\text{ \%}$ direct tensile strain capacity ($w_c = 70.0\ \mu\text{m}$).

Main contribution

• Micromechanical Deconstruction of Waste Selvage Fibers: Proved that PE filaments govern $>90\text{ \%}$ of composite tensile ductility and fiber bridging, while GF and PET fibers rupture prematurely due to inclination stress concentrations and low tensile strength.
• Single-Fiber Pullout Characterization:
• PE fiber: Pure frictional debonding and pullout ($\tau_0 = \mathbf{1.45\text{ MPa}}, G_d = 0, \beta = 0$).
• GF fiber: Chemical debonding ($G_d = 1.81\text{--}3.37\text{ J/m}^2$) followed by brittle rupture at 1686 MPa.
• PET fiber: High stretching followed by rupture at 383 MPa.
• Theoretical Fiber Bridging & PSH Verification:
• SE-15 achieved $\sigma_{B,peak} = 11.07\text{ MPa}$, $J_b' = 135.9\text{ J/m}^2$, $SPI = 2.26$, and $EPI = 3.40$, rigorously satisfying the conditions for steady-state flat crack propagation.
• GF-15 ($EPI = 0.04$) and PET-15 ($EPI = 0.29$) catastrophically failed the energy criterion.

Evidence summary

• Single Fiber Pullout & Matrix Toughness:
• PE: $\tau_0 = 1.45\text{ MPa}, G_d = 0, \beta = 0$ (Table 7 & Fig. 9a, Pages 10–11).
• GF: $G_d = 1.81\text{--}3.37\text{ J/m}^2$, rupture at $1686\text{ MPa}$ (Fig. 9b).
• PET: $\tau_0 = 1.02\text{--}1.89\text{ MPa}$, rupture at $383\text{ MPa}$ (Fig. 9c).
• Matrix: $K_m = 0.65 \pm 0.05\text{ MPa}\cdot\text{m}^{1/2}, E_m = 10.6\text{ GPa}, J_{tip} = 39.9\text{ J/m}^2$ (Page 11).
• Direct Uniaxial Tensile Properties & Cracking:
• SE-15 (Selvage): $f_c = \mathbf{63.2 \pm 2.43\text{ MPa}}$, $\sigma_{tu} = \mathbf{8.01 \pm 0.98\text{ MPa}}$, $\epsilon_{ts} = \mathbf{5.25 \pm 0.71\text{ \%}}$, $\sigma_{cr} = 3.55\text{ MPa}$, 59.9 cracks, $l_s = 1.34\text{ mm}$, $w_c = \mathbf{70.0\ \mu\text{m}}$ (Tables 4–6 & Figs. 7–8, Pages 6–9).
• PE-15 (Virgin PE): $f_c = 63.8\text{ MPa}$, $\sigma_{tu} = 12.51\text{ MPa}$, $\epsilon_{ts} = 5.96\text{ \%}$, 88.3 cracks, $w_c = 54.2\ \mu\text{m}$.
• GF-15: $f_c = 52.7\text{ MPa}$, $\sigma_{tu} = 5.45\text{ MPa}$, $\epsilon_{ts} = 0.03\text{ \%}$.
• PET-15: $f_c = 62.4\text{ MPa}$, $\sigma_{tu} = 2.53\text{ MPa}$, $\epsilon_{ts} = 0.20\text{ \%}$.
• Fiber Bridging & PSH Criteria:
• SE-15: $\sigma_{B,peak} = 11.07\text{ MPa}, J_b' = 135.9\text{ J/m}^2, \mathbf{SPI = 2.26 > 1.3, EPI = 3.40 > 2.7}$ (Tables 8–9 & Figs. 10–12, Pages 11–14).
• PE-15: $\sigma_{B,peak} = 13.37\text{ MPa}, J_b' = 177.8\text{ J/m}^2, SPI = 3.50, EPI = 4.46$.

Linked Atlas nodes

• 05_experiments/single_fiber_pullout.md
• 02_concepts/fiber_bridging_law.md
• 02_concepts/strain_hardening_criteria.md
• 04_material_systems/green_ecc.md

Relationship to Victor Li book

• Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
• Directly supports Chapter 4 (Micromechanics) and Chapter 5 (Multiple Cracking Criteria) by validating the Kanda-Li PSH design indices on upcycled hybrid textile fibers, proving that $81\text{ vol. \%}$ PE filaments provide pure frictional debonding ($\tau_0 = 1.45\text{ MPa}$) that satisfies both PSH criteria ($SPI = 2.26, EPI = 3.40$), enabling recycled selvage ECC to achieve $63.2\text{ MPa}$ compressive strength, $8.01\text{ MPa}$ tensile strength, and $5.25\text{ \%}$ direct tensile strain capacity.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (in primary_data/IJP08525E_From textile waste_JBE.pdf)
• Text extracted: yes (PyMuPDF, 16 pages)
• DOI verified: yes (10.1016/j.jobe.2025.112964)
• Page/figure/table verified: yes (all checked in PDF text)
• Claim-evidence matrix ready: yes

Cautions

• Glass core fibers and PET wrapping fibers rupture prematurely, contributing negligibly to tensile ductility and slightly widening crack widths ($70\ \mu\text{m}$ vs $54\ \mu\text{m}$).
• Manual unraveling was used in lab testing; automated yarn separation is required for mass production.