Park et al. (2025) — Length Effects of Recycled PE Selvage Fibers in Engineered Cementitious Composites

Citation

Se-Eon Park, Huy Hoàng Nguyễn, Yun Yong Kim, Youngsang Kim, Bang Yeon Lee (2025). Length effects of PE-based selvage fibers on fresh, fiber dispersion, and tensile properties of engineered cementitious composites. Journal of Sustainable Cement-Based Materials, 14(2), 327–337.

• DOI: 10.1080/21650373.2024.2441432
• Atlas layer: supporting
• Related Victor Li book chapter: Chapter 4: Micromechanics-Based Material Design & Chapter 5: Multiple Cracking Criteria
• Source PDF: primary_data/park-2025-length-effects-of-pe-based-selvage.pdfIJP08125E_Length effects of PE based selvage_vol.pdf`
• Extracted text: secondary_data/full_texts/park-2025-length-effects-of-pe-based-selvage_full_text.mdsecondary_data/full_texts/IJP08125E_Length effects of PE based selvage_vol_full_text.md`
• Source note: secondary_data/source_notes/park-2025-length-effects-of-pe-based-selvage_source_note.mdsecondary_data/source_notes/IJP08125E_Length effects of PE based selvage_vol_source_note.md`

Why this paper matters

Systematically evaluates the influence of recycled PE-based selvage fiber length (5, 10, and 15 mm at 1.75 vol. %) on fresh flowability, SEM/EDS carbon-mapped fiber dispersion ($\alpha_f \approx 0.40$), and direct tensile performance of ECC. Proves that 15 mm fibers (F-15) achieve a compressive strength of $61.5\text{ MPa}$, a tensile strength of $8.04\text{ MPa}$, and a tensile strain capacity of $7.24 \pm 0.39\text{ \%}$ (71.5 cracks, $l_s = 1.12\text{ mm}$, $w_c = 80.0\ \mu\text{m}$, and back-calculated $\tau_0 = 1.132\text{ MPa}$), while even 5 mm short fibers (F-5) sustain $5.13\text{ \%}$ ductility (double standard M45 ECC).

Main contribution

• Fiber Length Optimization & Tensile Performance: Increasing selvage fiber length from 5 mm to 15 mm raised compressive strength to $61.5\text{ MPa}$ (+5.4 %), tensile strength to $8.04\text{ MPa}$ (+51.7 %), and tensile strain capacity to $7.24\text{ \%}$ (+41.3 %) with low variability ($\text{CoV} = 5.4\text{ \%}$).
• 5 mm Short Fiber Ductility: Even ultra-short 5 mm selvage fibers (F-5) achieved $5.13 \pm 0.67\text{ \%}$ tensile strain capacity ($f_c = 58.4\text{ MPa}, \sigma_{tu} = 5.30\text{ MPa}$), exceeding standard M45 ECC with 12 mm PVA fibers.
• Crack Spacing & Interfacial Bond Modeling: Validated the Aveston-Kelly-Wu 2D crack spacing formulation ($l_s = 1.12\text{ mm}$ in F-15 vs $1.61\text{ mm}$ in F-5) with back-calculated interfacial bond $\tau_0 = \mathbf{1.132\text{ MPa}}$ (error $< 5.3\text{ \%}$), while proving fiber dispersion ($\alpha_f \approx 0.40$) remains unaffected across 5–15 mm cut lengths.

Evidence summary

• Fresh Property & Compressive Strength:
• Mini-slump flow: F-5 ($133.2\text{ mm}$) > F-10 ($129.2\text{ mm}$) > F-15 ($122.5\text{ mm}$) (Table 4, Page 6).
• 28-day Compressive strength: F-15 ($61.5 \pm 1.8\text{ MPa}$), F-10 ($59.7 \pm 1.2\text{ MPa}$), F-5 ($58.4 \pm 4.2\text{ MPa}$) (Table 5, Page 7).
• Direct Uniaxial Tensile Properties:
• F-15 (15 mm): $\sigma_{tu} = \mathbf{8.04 \pm 0.59\text{ MPa}}$, $\epsilon_{ts} = \mathbf{7.24 \pm 0.39\text{ \%}}$, $\sigma_{cr} = 2.89\text{ MPa}$, $U_t = 0.395\text{ MPa}\cdot\text{m/m}$, $f_{ts}/f_{cr} = 2.78$ (Table 6 & Figs. 10–11, Pages 7–8).
• F-10 (10 mm): $\sigma_{tu} = 7.71 \pm 0.82\text{ MPa}$, $\epsilon_{ts} = 6.73 \pm 0.59\text{ \%}$, $\sigma_{cr} = 2.88\text{ MPa}$, $U_t = 0.356\text{ MPa}\cdot\text{m/m}$, $f_{ts}/f_{cr} = 2.66$.
• F-5 (5 mm): $\sigma_{tu} = 5.30 \pm 0.37\text{ MPa}$, $\epsilon_{ts} = \mathbf{5.13 \pm 0.67\text{ \%}}$, $\sigma_{cr} = 2.82\text{ MPa}$, $U_t = 0.208\text{ MPa}\cdot\text{m/m}$, $f_{ts}/f_{cr} = 1.88$.
• Cracking Patterns & Frictional Bond Back-Calculation:
• Crack count ($\eta_c$): F-15 (71.5) > F-10 (66.4) > F-5 (50.0) (Table 8, Page 8).
• Crack spacing ($l_s$): F-15 ($1.12\text{ mm}$) vs F-5 ($1.61\text{ mm}$).
• Crack width ($w_c$): F-15 ($80.0\ \mu\text{m}$), F-10 ($81.6\ \mu\text{m}$), F-5 ($82.1\ \mu\text{m}$) (average $81.2\ \mu\text{m}$).
• Model fit: Optimal frictional bond $\tau_0 = \mathbf{1.132\text{ MPa}}$ (error $< 5.3\text{ \%}$) (Eqs. 3–4, Pages 8–10).
• Fiber Dispersion Coefficients:
• $\alpha_f = 0.392 \pm 0.009$ (F-5), $0.401 \pm 0.011$ (F-10), $0.396 \pm 0.006$ (F-15) (Table 9, Page 10).

Linked Atlas nodes

• 02_concepts/fiber_dispersion.md
• 05_experiments/crack_width_distribution.md
• 04_material_systems/green_ecc.md
• 05_experiments/direct_tensile_test.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 Aveston-Kelly-Wu theoretical crack spacing model for recycled selvage fibers, demonstrating that fiber length (5 to 15 mm) does not compromise dispersion homogeneity ($\alpha_f \approx 0.40$), enabling 15 mm fibers to deliver $7.24\text{ \%}$ tensile strain capacity with $\tau_0 = 1.132\text{ MPa}$ and 5 mm fibers to achieve $5.13\text{ \%}$ ductility.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (in primary_data/IJP08125E_Length effects of PE based selvage_vol.pdf)
• Text extracted: yes (PyMuPDF, 12 pages)
• DOI verified: yes (10.1080/21650373.2024.2441432)
• Page/figure/table verified: yes (all checked in PDF text)
• Claim-evidence matrix ready: yes

Cautions

• 15 mm fibers slightly lower mini-slump flow ($122.5\text{ mm}$ vs $133.2\text{ mm}$).
• Coarse aggregates must be excluded to maintain steady-state flat crack propagation.