Choi et al. (2015) — Rheological & Mechanical Properties of FRAAC
Citation
Se-Jin Choi, Jeong-Il Choi, Jin-Kyu Song, Bang Yeon Lee (2015). Rheological and mechanical properties of fiber-reinforced alkali-activated composite. Construction and Building Materials, 96, 112–118.
- DOI:
10.1016/j.conbuildmat.2015.07.182 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 5: Processing and Rheology of ECC (also Chapter 9)
- Source PDF:
primary_data/choi-2015-rheological-and-mechanical-properties-of.pdfIJP02115E_Rheological and mechanical properties of FRAAC_CBM.pdf` - Extracted text:
secondary_data/full_texts/choi-2015-rheological-and-mechanical-properties-of_full_text.mdsecondary_data/full_texts/IJP02115E_Rheological and mechanical properties of FRAAC_CBM_full_text.md` - Source note:
secondary_data/source_notes/choi-2015-rheological-and-mechanical-properties-of_source_note.mdsecondary_data/source_notes/IJP02115E_Rheological and mechanical properties of FRAAC_CBM_source_note.md`
Why this paper matters
Proves that cementless alkali-activated slag composites can achieve ultra-low plastic viscosity ($\mu_p = 0.86\text{ Pa}\cdot\text{s}$, suitable for grouting/injection) while delivering robust direct tensile strain-hardening ($\epsilon_u = 2.38\text{ \%}$) with only 1.3 vol. % of 8 mm PVA fibers.
Main contribution
- Sub-1.0 Pa·s Rheology with Strain-Hardening: Developed an alkali-activated composite with low plastic viscosity ($0.86\text{ Pa}\cdot\text{s}$) and low yield stress ($18\text{ Pa}$) that overcomes the conventional $5\text{ Pa}\cdot\text{s}$ minimum viscosity threshold.
- Low Fiber Volume Fraction: Achieved $2.38 \pm 0.58\text{ \%}$ tensile strain capacity and 2.26 MPa tensile strength using only 1.3 vol. % short PVA fibers ($8\text{ mm}$).
- Micromechanical Verification: Confirmed single-fiber pullout parameters ($\tau_0 = 1.27\text{ MPa}, G_d = 1.13\text{ J/m}^2$) and matrix fracture energy ($J_{tip} = 12.5\text{ J/m}^2$), proving that $J_b'/J_{tip} = 1.67 > 1.0$ governs multiple cracking.
Evidence summary
- Direct Tensile Response: $\epsilon_u = 2.38\text{ \%}$, $\sigma_{tu} = 2.26\text{ MPa}$, first cracking strength $1.53\text{ MPa}$ for mix M40-1.3 (Table 6, Page 116).
- Rheological Values: Plastic viscosity $0.86\text{ Pa}\cdot\text{s}$, yield stress $18\text{ Pa}$, flow time $< 18\text{ s}$, slump flow $240\text{ mm}$ (Section 4.1, Page 114–115).
- Compressive Strength: $18.3\text{ MPa}$ (M40-1.3) and $18.5\text{ MPa}$ (M40-1.0) (Table 5, Page 115).
- Energy Index: Saturated PSH energy ratio $J_b'/J_{tip} = 1.67$ for M40-1.3 (Table 8, Page 117).
Linked Atlas nodes
02_concepts/processing_rheology.md04_material_systems/green_ecc.md02_concepts/strain_hardening_criteria.md02_concepts/interface_properties.md05_experiments/direct_tensile_test.md
Relationship to Victor Li book
- Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
- Extends Chapter 5 (Rheology) and Chapter 9 (Green ECC) by establishing that micromechanical tailoring allows low-viscosity grouts to retain steady-state multiple cracking.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
02_concepts/processing_rheology.md |
Cementless alkali-activated slag composite with plastic viscosity $< 1.0\text{ Pa}\cdot\text{s}$ achieves 2.38 % tensile ductility with 1.3 vol. % PVA fibers | Mix M40-1.3 achieved $\mu_p = 0.86\text{ Pa}\cdot\text{s}$, $\tau_y = 18\text{ Pa}$, and $\epsilon_u = 2.38\text{ \%}$ | Page 112 & 116 / Table 6 / Fig. 9 | verified_from_pdf |
02_concepts/strain_hardening_criteria.md |
Saturated multiple cracking in low-viscosity FRAAC is governed by an energy performance index $J_b'/J_{tip} = 1.67$ | Saturated multiple cracking confirmed with $J_b'/J_{tip} = 1.67$ and stress index 1.48 | Page 116 & 117 / Table 8 / Fig. 10 | verified_from_pdf |
02_concepts/interface_properties.md |
Single-fiber pullout in $w/b=0.40$ slag matrix demonstrates balanced bonding ($G_d = 1.13\text{ J/m}^2, \tau_0 = 1.27\text{ MPa}$) | Direct single fiber pullout tests yielded $\tau_0 = 1.27\text{ MPa}$ and $G_d = 1.13\text{ J/m}^2$ for M40 | Page 116 / Table 7 | verified_from_pdf |
Verification status
- PDF preserved: yes (in
primary_data/IJP02115E_Rheological and mechanical properties of FRAAC_CBM.pdf) - Text extracted: yes (PyMuPDF, 7 pages)
- DOI verified: yes (
10.1016/j.conbuildmat.2015.07.182) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- Designed for low-viscosity grouting applications; compressive strength is ~18 MPa.