Nguyễn et al. (2024) — Crack-Healing and Cost Efficiency of Recycled Selvage Fiber ECC

Citation

Huy Hoàng Nguyễn, Phương Hoàng Nguyễn, Quang-Hiếu Lương, Se-Eon Park, Youngsang Kim, Bang Yeon Lee (2024). Crack-healing of cost-effective engineered cementitious composites reinforced by recycled selvage fiber. Cement and Concrete Composites, 154, 105776.

• DOI: 10.1016/j.cemconcomp.2024.105776
• Atlas layer: extension
• Related Victor Li book chapter: Chapter 8: Self-Healing and Durability & Chapter 9: Green ECC
• Source PDF: primary_data/nguyen-2024-crack-healing-of-cost-effective-engineered-cementitious.pdfIJP07924E_Crack healing eCC selvage_CCC.pdf`
• Extracted text: secondary_data/full_texts/nguyen-2024-crack-healing-of-cost-effective-engineered-cementitious_full_text.mdsecondary_data/full_texts/IJP07924E_Crack healing eCC selvage_CCC_full_text.md`
• Source note: secondary_data/source_notes/nguyen-2024-crack-healing-of-cost-effective-engineered-cementitious_source_note.mdsecondary_data/source_notes/IJP07924E_Crack healing eCC selvage_CCC_source_note.md`

Why this paper matters

Demonstrates that industrial textile waste (18 mm cut recycled selvage fiber RSF: 81 % PE, 7 % glass, 12 % PET) can fully substitute virgin PE fibers at $1.5\text{ vol. \%}$ in sustainable slag-modified ECC (ECC-S-RSF), achieving a compressive strength of $83.5\text{ MPa}$, a direct tensile strain capacity of $10.24 \pm 1.32\text{ \%}$, and complete crack healing up to $80\ \mu\text{m}$ (expanding the standard $50\ \mu\text{m}$ threshold), with post-healing reloading tensile strength surging to $10.79\text{ MPa}$ (+19.9 %) while slashing material costs by 3.5–26x.

Main contribution

• 83.5 MPa Strength & 10.24 % Ductility with Recycled Fibers: Slag-incorporated composite (ECC-S-RSF, 50 wt% GGBS, 5 wt% crumb rubber, 1.5 vol. % RSF) achieved $83.5\text{ MPa}$ compressive strength and $10.24 \pm 1.32\text{ \%}$ direct tensile strain capacity ($\sigma_{tu} = 9.00\text{ MPa}, SPI = 1.94$).
• Unrivaled Cost Efficiency: Cost efficiency index ($C_e$) of ECC-S-RSF was 26.3 times lower than existing recycled-fiber ECCs and 3.5 times lower than ultra-high-performance virgin PE-ECCs ($250\text{ \$/m}^3$).
• Expanded 80 $\mu\text{m}$ Self-Healing & Reloading Surge: After 2 % pre-strain and 56 days of water immersion, complete crack closure was achieved up to $80\ \mu\text{m}$; post-healing reloading tensile strength reached $10.79 \pm 0.02\text{ MPa}$ (+19.9 %) with $5.16\text{ \%}$ residual ductility, driven by $\text{CaCO}_3$ and C-S-H precipitation.

Evidence summary

• Mechanical Properties (28d/84d):
• ECC-S-RSF: $f_c = \mathbf{83.5\text{ MPa}}$, $\sigma_{tu} = \mathbf{9.00 \pm 1.09\text{ MPa}}$, $\epsilon_{tu} = \mathbf{10.24 \pm 1.32\text{ \%}}$, $\sigma_{fc} = 4.65\text{ MPa}$, 42.5 cracks ($w_c = 193.13\ \mu\text{m}, s_c = 1.92\text{ mm}$), $SPI = 1.94$ (Table 4 & Figs. 6–8, Pages 4–6).
• ECC-F-RSF: $f_c = 53.5\text{ MPa}$ ($\rho_m = 1.85\text{ g/cm}^3$), $\sigma_{tu} = 7.58 \pm 0.50\text{ MPa}$, $\epsilon_{tu} = 4.67 \pm 1.19\text{ \%}$, 12.7 cracks ($w_c = 308.05\ \mu\text{m}$).
• Cost Effectiveness:
• $C_e$ of ECC-S-RSF was 26.3x and 3.5x lower than recycled-fiber ECC and virgin PE-ECC, respectively (Fig. 10 & Table 6, Page 6).
• Crack Healing & Reloading (2.0 % pre-strain, 56d water curing):
• Healing threshold: Complete closure achieved up to $80\ \mu\text{m}$ (Figs. 11–13, Pages 7–8).
• Stiffness Recovery: $R_s = +13.3\text{ \%p}$ for ECC-S-RSF vs $+3.3\text{ \%p}$ for ECC-F-RSF (Fig. 14, Page 8).
• Post-Healing Reloading Tensile Strength ($f_{ts-h}$):
  • ECC-S-RSF: $10.79 \pm 0.02\text{ MPa}$ (+19.9 % over virgin), residual strain capacity $5.16 \pm 0.40\text{ \%}$ (Table 7 & Fig. 15, Pages 8–9).
  • ECC-F-RSF: $8.49 \pm 0.69\text{ MPa}$ (+12.0 %), residual strain capacity $2.56 \pm 0.55\text{ \%}$.
• Mineralogy: SEM/EDS confirmed $\text{CaCO}_3$ ($\text{Ca/Si} \ge 2.0$) at crack mouths and C-S-H gel ($\text{Ca/Si} < 2.0$) in interiors (Figs. 18–20, Pages 10).

Linked Atlas nodes

• 04_material_systems/green_ecc.md
• 04_material_systems/self_healing_ecc.md
• 02_concepts/strain_hardening_criteria.md
• 05_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) and Chapter 9 (Green ECC) by establishing that recycled multi-filament selvage fibers (RSF) fully replicate virgin PE performance, delivering 83.5 MPa compressive strength, 10.24 % direct tensile strain capacity, an expanded $80\ \mu\text{m}$ crack self-healing threshold, and 10.79 MPa reloading tensile strength (+19.9 %) at a fraction of the material cost.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (in primary_data/IJP07924E_Crack healing eCC selvage_CCC.pdf)
• Text extracted: yes (PyMuPDF, 12 pages)
• DOI verified: yes (10.1016/j.cemconcomp.2024.105776)
• Page/figure/table verified: yes (all checked in PDF text)
• Claim-evidence matrix ready: yes

Cautions

• Resonant frequency stiffness recovery is modest (+13.3 %p) due to incomplete inner-crack carbonation.
• Fly ash-based mix (ECC-F-RSF) produces wider initial cracks ($308\ \mu\text{m}$) and lower healing rates.