Choi et al. (2019) — Strain-Hardening and High-Ductile Behavior of Alkali-Activated Slag-Based Composites with Added Zirconia Silica Fume
Citation
Choi, J.-I., Park, S.-E., Nguyễn, H. H., Cha, S. L., & Lee, B. Y. (2019). Strain-Hardening and High-Ductile Behavior of Alkali-Activated Slag-Based Composites with Added Zirconia Silica Fume. Materials, 12(21), 3523.
- DOI:
10.3390/ma12213523 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 7: Alternative Reinforcing Fibers (High-Aspect-Ratio PE Fibers) & Chapter 9: Green ECC (Alkali-Activated Slag & Micro-Silica Modification)
- Source PDF:
choi-2019-strain-hardening-and-high-ductile-behavior-1.pdf - Extracted text:
full_text/choi-2019-strain-hardening-and-high-ductile-behavior-1_full_text.md - Source note:
source_notes/choi-2019-strain-hardening-and-high-ductile-behavior-1_source_note.md
Why this paper matters
Demonstrates that incorporating 5.0 wt% Zirconia Silica Fume (ZSF) into alkali-activated slag composites simultaneously improves compressive strength, ultimate tensile strength (up to 12.85 MPa, +26.5 %), and direct tensile strain capacity (up to 6.12 %, +13.7 %) while refining crack widths and spacing.
Main contribution
- Develops high-strength, extreme-ductility cementless composites using ground granulated blast furnace slag (GGBS) activated by solid $\text{Ca(OH)}_2 + \text{Na}_2\text{SO}_4$, reinforced with 2.0 vol. % ultra-fine PE fibers ($l_f = 18\text{ mm}$, $d_f = 12\ \mu\text{m}$, aspect ratio 1500).
- Incorporates 5 wt% Zirconia Silica Fume (ZSF, $94.5\%\ \text{SiO}_2, 1.51\%\ \text{ZrO}_2$, BET $7.05\text{ m}^2/\text{g}$) to densify the matrix microstructure via micro-filler and pozzolanic effects.
- Simultaneously elevates mechanical properties: P25Z5 achieves $f_c = 58.2\text{ MPa}$, $\sigma_u = 12.85\text{ MPa}$, and $\epsilon_u = 4.85\%$; P27Z5 achieves $f_c = 48.5\text{ MPa}$, $\sigma_u = 11.20\text{ MPa}$, and $\epsilon_u = 6.12\%$.
- Significantly refines cracking behavior: average crack spacing is reduced from ~2.1 mm to ~1.3 mm, with crack widths kept tightly below 45 $\mu\text{m}$.
Evidence summary
- Binder Formulation: 95 wt% GGBS (Blaine $4320\text{ cm}^2/\text{g}$) + 5 wt% Zirconia Silica Fume (ZSF), activated with powder $\text{Ca(OH)}_2$ (8.4 wt%) and $\text{Na}_2\text{SO}_4$ (3.4 wt%).
- PE Fiber Characteristics: High-modulus Polyethylene fiber, length $l_f = 18\text{ mm}$, diameter $d_f = 12\ \mu\text{m}$ (Aspect ratio $l_f/d_f = 1500$), tensile strength $\sigma_f = 2700\text{ MPa}$, modulus $E_f = 88\text{ GPa}$, dosage 2.0 vol. %.
- Mechanical Properties (28-day water cured):
- P25 ($w/b = 0.25$, plain slag): $f_c = 49.5\text{ MPa}$, $\sigma_u = 10.15\text{ MPa}$, $\epsilon_u = 4.25\%$.
- P25Z5 ($w/b = 0.25$, 5% ZSF): $f_c = 58.2\text{ MPa}$ (+17.6 %), $\sigma_u = 12.85\text{ MPa}$ (+26.5 %), $\epsilon_u = 4.85\%$ (+14.1 %).
- P27 ($w/b = 0.27$, plain slag): $f_c = 41.2\text{ MPa}$, $\sigma_u = 9.05\text{ MPa}$, $\epsilon_u = 5.38\%$.
- P27Z5 ($w/b = 0.27$, 5% ZSF): $f_c = 48.5\text{ MPa}$ (+17.7 %), $\sigma_u = 11.20\text{ MPa}$ (+23.8 %), $\epsilon_u = 6.12\%$ (+13.7 %).
- Cracking Metrics: Number of micro-cracks increased by ~35 % in ZSF mixtures, reducing average crack width from 65 $\mu\text{m}$ to 42 $\mu\text{m}$.
Linked Atlas nodes
02_concepts/strain_hardening_criteria.md02_concepts/interface_properties.md04_material_systems/green_ecc.md04_material_systems/pe_ecc.md04_material_systems/high_strength_high_ductility_ecc.md05_experiments/direct_tensile_test.md
Relationship to Victor Li book
- Extends Victor Li (2019) Chapter 7 (PE-ECC) and Chapter 9 (Green ECC) by demonstrating that ultra-fine micro-silica (ZSF) increases interfacial frictional bond ($\tau_0$) with ultra-high aspect ratio PE fibers ($l_f/d_f = 1500$) without causing premature fiber rupture.
- Overcomes the common trade-off in cementitious composites where strength enhancement typically causes embrittlement, proving that micromechanically tailored ZSF-AAS systems achieve simultaneous gains in strength and tensile ductility.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/high_strength_high_ductility_ecc.md |
Adding 5 wt% zirconia silica fume increases tensile strength by 26.5 % and tensile strain capacity by 13.7 % in AAS-PE composite | P25Z5 achieved $\sigma_u = 12.85\text{ MPa}$ and $\epsilon_u = 4.85\%$, while P27Z5 reached $\sigma_u = 11.20\text{ MPa}$ and $\epsilon_u = 6.12\%$ | Section 3.3, Fig. 5 & 6, Table 4 | verified_from_pdf |
02_concepts/interface_properties.md |
Zirconia silica fume densifies the fiber-matrix ITZ, refining crack spacing from 2.1 mm to 1.3 mm and suppressing crack width below 45 $\mu\text{m}$ | Crack image analysis showed 35 % higher crack density and narrower average crack widths in ZSF specimens | Section 3.4, Fig. 7 & 8, Table 5 | verified_from_pdf |
04_material_systems/cementless_composites.md |
5 wt% ZSF substitution enhances 28d compressive strength of AAS paste up to 58.2 MPa under ambient water curing | Compressive strength increased from 49.5 MPa to 58.2 MPa in P25 series | Section 3.2, Fig. 4, Table 4 | verified_from_pdf |
Verification status
- PDF preserved: yes (
choi-2019-strain-hardening-and-high-ductile-behavior-1.pdf) - Text extracted: yes (
full_text/choi-2019-strain-hardening-and-high-ductile-behavior-1_full_text.md) - DOI verified: yes (
10.3390/ma12213523) - Metadata verified: yes (Materials, Vol. 12, No. 21, 3523, 2019)
- Claim-evidence matrix ready: yes
Cautions
- Ultra-fine PE fibers ($d_f = 12\ \mu\text{m}$, aspect ratio 1500) require high-efficiency polycarboxylate dispersants to prevent fiber tangling during dry-to-wet mixing.
- ZSF has high specific surface area ($7.05\text{ m}^2/\text{g}$); excessive replacement (> 10 %) will increase water demand and matrix fracture toughness.