Lee et al. (2012) — Strain-Hardening Fiber Reinforced Alkali-Activated Mortar
Citation
Bang Yeon Lee, Chang-Geun Cho, Hyun-Jin Lim, Jin-Kyu Song, Keun-Hyeok Yang, Victor C. Li (2012). Strain hardening fiber reinforced alkali-activated mortar – A feasibility study. Construction and Building Materials, 37, 15–20.
- DOI:
10.1016/j.conbuildmat.2012.06.007 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 9: Green ECC and Sustainability (also Chapter 4)
- Source PDF:
primary_data/lee-2012-strain-hardening-fiber-reinforced-alkali-activated.pdfIJP01112E_Strain hardening cementless_CBM.pdf` - Extracted text:
secondary_data/full_texts/lee-2012-strain-hardening-fiber-reinforced-alkali-activated_full_text.mdsecondary_data/full_texts/IJP01112E_Strain hardening cementless_CBM_full_text.md` - Source note:
secondary_data/source_notes/lee-2012-strain-hardening-fiber-reinforced-alkali-activated_source_note.mdsecondary_data/source_notes/IJP01112E_Strain hardening cementless_CBM_source_note.md`
Why this paper matters
The foundational, world-first paper (co-authored by Victor C. Li) demonstrating that a 100 % cement-free alkali-activated slag (GGBS) mortar can achieve robust tensile strain-hardening ($\epsilon_u \approx 4.5\text{ \%}$) and tight micro-crack control (~20 $\mu\text{m}$).
Main contribution
- First Proof of Cementless PSH: Achieved an ultimate direct tensile strain capacity of $4.48 \pm 0.77\text{ \%}$ (peak 4.7 %) in an OPC-free GGBS mortar, representing a 224-fold increase over plain matrix (0.020 %).
- Activator System Formulation: Optimized a solid activator mixture of 7.5 wt. % $\text{Ca(OH)}_2$ and 1.0 wt. % $\text{Na}_2\text{SO}_4$ at $w/b=0.340$, yielding 30.6 MPa compressive strength and 4.69 MPa ultimate tensile strength.
- Tight Crack Control & Extreme Bending: Verified average residual crack widths of $20.2\ \mu\text{m}$ and a massive flexural deflection of $74.3\text{ mm}$ in $10\text{ mm}$ thin panels.
Evidence summary
- Direct Tensile Performance: Average $\epsilon_u = 4.48\text{ \%}$, tensile strength $\sigma_{tu} = 4.69\text{ MPa}$, first cracking strength $3.87\text{ MPa}$ for mix M1 (Table 7, Page 18).
- Compressive Strength: 28-day cube strength of $30.6\text{ MPa}$ (M1) and $25.7\text{ MPa}$ (M3) (Table 6, Page 17).
- Crack Characteristics: Residual crack width $20.2\ \mu\text{m}$ under unloaded state with $2 \sim 3\text{ mm}$ crack spacing (Section 3.3, Page 18).
- Flexural Capacity: Flexural strength $12.7\text{ MPa}$ and deflection $74.3\text{ mm}$ (Table 8, Page 19).
Linked Atlas nodes
04_material_systems/green_ecc.md02_concepts/sustainability.md02_concepts/strain_hardening_criteria.md05_experiments/direct_tensile_test.md05_experiments/crack_width_distribution.md
Relationship to Victor Li book
- Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
- Seminal extension of Chapter 9 (Green ECC), validating that the micromechanical PSH design criteria apply fully to cementless alkali-activated slag systems.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/green_ecc.md |
100 % cementless alkali-activated slag mortar with 2.0 vol. % PVA fibers achieves 4.48 % direct tensile strain capacity | M1 mix achieved $\epsilon_u = 4.48\text{ \%}$ (peak 4.7 %) and $\sigma_{tu} = 4.69\text{ MPa}$ in uniaxial tension | Page 15 & 18 / Abstract & Table 7 | verified_from_pdf |
02_concepts/strain_hardening_criteria.md |
Higher stress performance index (1.21 in M1 vs 1.11 in M2) maximizes multiple cracking saturation in cementless ECC | M1 with $w/b=0.340$ achieved stress performance index of 1.21, developing highest tensile ductility | Page 18 / Section 3.3 | Table 7 |
05_experiments/crack_width_distribution.md |
Cementless slag ECC maintains tightly controlled residual crack widths averaging ~20 $\mu\text{m}$ | Unloaded residual crack width of M1 measured at $20.2\ \mu\text{m}$ under optical microscopy | Page 18 / Section 3.3 | Fig. 4 |
Verification status
- PDF preserved: yes (in
primary_data/IJP01112E_Strain hardening cementless_CBM.pdf) - Text extracted: yes (PyMuPDF, 6 pages)
- DOI verified: yes (
10.1016/j.conbuildmat.2012.06.007) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- Single fiber pullout micromechanical parameters were not directly measured in this feasibility study (noted for future work).