Nguyễn et al. (2021) — Ultra-Ductile Fly Ash EGC with 13.7% Strain Capacity
Citation
Huy Hoàng Nguyễn, Quang-Hiếu Lương, Jeong-Il Choi, Ravi Ranade, Victor C. Li, Bang Yeon Lee (2021). Ultra-ductile behavior of fly ash-based engineered geopolymer composites with a tensile strain capacity up to 13.7%. Cement and Concrete Composites, 122, 104133.
- DOI:
10.1016/j.cemconcomp.2021.104133 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 9: Green ECC (also Chapter 4)
- Source PDF:
primary_data/nguyen-2021-ultra-ductile-behavior-of-fly-ash-based.pdfIJP06021E_Ultra ductile behavior FGC1_CCC.pdf` - Extracted text:
secondary_data/full_texts/nguyen-2021-ultra-ductile-behavior-of-fly-ash-based_full_text.mdsecondary_data/full_texts/IJP06021E_Ultra ductile behavior FGC1_CCC_full_text.md` - Source note:
secondary_data/source_notes/nguyen-2021-ultra-ductile-behavior-of-fly-ash-based_source_note.mdsecondary_data/source_notes/IJP06021E_Ultra ductile behavior FGC1_CCC_source_note.md`
Why this paper matters
Landmark co-authored paper with Victor C. Li and Ravi Ranade demonstrating that fly ash-based geopolymer composites reinforced with 1.75 vol. % PE fibers (UD-EGC15, SMP/SH = 1.5) achieve a world-record direct tensile strain capacity of 13.68 % (13.7 %) with $\sigma_{tu} = 6.79\text{ MPa}$, enabled by an ultra-low matrix fracture energy ($J_{tip} = 0.57\text{ J/m}^2$), complementary energy $J_b' = 184\text{ J/m}^2$, and an extraordinary energy performance index of $I_{EP} = 322$.
Main contribution
- World-Record 13.7 % Direct Tensile Ductility: Achieved a direct tensile strain capacity of $13.68 \pm 0.85\text{ \%}$ with $\sigma_{tu} = 6.79\text{ MPa}$ in UD-EGC15, exceeding the tensile ductility of structural reinforcing steel (7–14 %).
- Unprecedented PSH Energy Margin ($I_{EP} = 322$): Measured $K_m = 0.07\text{ MPa}\cdot\text{m}^{1/2}$ ($J_{tip} = 0.57\text{ J/m}^2$) and $\tau_0 = 0.55\text{ MPa}$, yielding $J_b' = 184\text{ J/m}^2$ and $I_{EP} = 322$ (119x design criterion).
- Lightweight & High Tensile Efficiency: Delivered lightweight density ($\rho_h = 1.44\text{--}1.83\text{ g/cm}^3$) and an unprecedented tensile-to-compressive strength ratio of 35.1 % to 45.2 %.
Evidence summary
- Direct Tensile Response (28d):
UD-EGC15: $\epsilon_{ts} = 13.68 \pm 0.85\text{ \%}$ (Peak 13.7 %), $\sigma_{tu} = 6.79\text{ MPa}$, $\sigma_{fc} = 3.70\text{ MPa}$, Toughness = $0.71\text{ MPa}\cdot\text{m/m}$, $f_{ts}/f_c = 35.1\text{ \%}$ (Tables 4 & 5, Pages 5–6).UD-EGC20: $\epsilon_{ts} = 12.26 \pm 0.71\text{ \%}$, $\sigma_{tu} = 8.10 \pm 0.42\text{ MPa}$, $\sigma_{fc} = 4.63\text{ MPa}$, Toughness = $0.78\text{ MPa}\cdot\text{m/m}$, $f_{ts}/f_c = 36.1\text{ \%}$.UD-EGC10: $\epsilon_{ts} = 12.49\text{ \%}$, $\sigma_{tu} = 7.11\text{ MPa}$;UD-EGC25: $\epsilon_{ts} = 10.88\text{ \%}$, $\sigma_{tu} = 7.18\text{ MPa}$.- 28-Day Compressive Strength & Density: UD-EGC15 = $19.3\text{ MPa}$ ($1.66\text{ g/cm}^3$), UD-EGC20 = $22.4\text{ MPa}$ ($1.44\text{ g/cm}^3$) (Fig. 4, Page 4).
- Crack Microstructure: 77.5 saturated cracks with 1.00 mm crack spacing and $136.7\ \mu\text{m}$ width (Table 6, Page 7).
- Micromechanical & PSH Parameters: $K_m = 0.07\text{ MPa}\cdot\text{m}^{1/2}$, $J_{tip} = 0.57\text{ J/m}^2$, $\tau_0 = 0.55\text{ MPa}$, $J_b' = 184\text{ J/m}^2$, $I_{EP} = 322$, $I_{SP} = 1.84$ (Tables 7 & 8, Pages 7–10).
Linked Atlas nodes
04_material_systems/green_ecc.md02_concepts/strain_hardening_criteria.md02_concepts/interface_properties.md05_experiments/crack_width_distribution.md05_experiments/single_fiber_pullout.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 9 (Green ECC) and Chapter 4 (co-authored with Victor C. Li), proving that fly ash geopolymers can achieve 13.7 % direct tensile ductility by micromechanically minimizing $J_{tip}$ ($0.57\text{ J/m}^2$) to achieve $I_{EP} = 322$.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/green_ecc.md |
Fly ash-based geopolymer composite (UD-EGC15) achieves a world-record direct tensile strain capacity of 13.68 % with 6.79 MPa tensile strength | Direct tension tests verified $\epsilon_{ts} = 13.68\text{ \%}$, $\sigma_{tu} = 6.79\text{ MPa}$, and density $<1.83\text{ g/cm}^3$ | Page 104133:1 & 6 / Table 4 / Fig. 6 & 7 | verified_from_pdf |
02_concepts/strain_hardening_criteria.md |
UD-EGC15 exhibits an ultra-low matrix fracture energy ($J_{tip} = 0.57\text{ J/m}^2$) and complementary energy $J_b' = 184\text{ J/m}^2$, delivering $I_{EP} = 322$ | ASTM E399 notch tests and pullout modeling confirmed $J_{tip}=0.57\text{ J/m}^2, J_b'=184.03\text{ J/m}^2, I_{EP}=322$ | Page 104133:7 & 10 / Table 7 & 8 / Fig. 10 | verified_from_pdf |
04_material_systems/green_ecc.md |
UD-EGC achieves an extraordinary tensile-to-compressive strength ratio of 35.1 % to 45.2 % with lightweight density ($1.44\text{--}1.83\text{ g/cm}^3$) | Tensile-to-compressive ratio reached 35.1–45.2 % with lightweight hardened density | Page 104133:4 & 6 / Table 5 / Fig. 4 | verified_from_pdf |
Verification status
- PDF preserved: yes (in
primary_data/IJP06021E_Ultra ductile behavior FGC1_CCC.pdf) - Text extracted: yes (PyMuPDF, 11 pages)
- DOI verified: yes (
10.1016/j.cemconcomp.2021.104133) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- Thermal curing (80 °C for 36 h) is required to trigger geopolymerization.
- Crack width ($\approx 137\ \mu\text{m}$) is wider than OPC-based ECC due to lower frictional shear ($\tau_0 = 0.55\text{ MPa}$).