Lee et al. (2012) — Strain hardening fiber reinforced alkali-activated...

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, Vol. 37, pp. 15-20.

DOI: 10.1016/j.conbuildmat.2012.06.007
Atlas layer: extension
Related Victor Li book chapter: Chapter 7: Alternative and Green Binders in ECC
Source PDF: lee-2012-strain-hardening-fiber-reinforced-alkali-activated.pdf
Extracted text: atlas/full_text/lee-2012-strain-hardening-fiber-reinforced-alkali-activated_full_text.md
Source note: atlas/source_notes/lee-2012-strain-hardening-fiber-reinforced-alkali-activated_source_note.md

Why this paper matters

First breakthrough feasibility study demonstrating that brittle cementless alkali-activated slag (AAS) mortar can achieve pseudo strain-hardening with tensile strain capacity up to 4.7% (mean 4.48%) and tight microcrack widths (<25 $\mu\text{m}$) using 2.0 vol% PVA fibers.

Main contribution

Developed the first strain-hardening cementless alkali-activated composite (AAS-PVA) achieving tensile strain capacity up to 4.7% (224 times that of the unreinforced matrix).
Characterized the influence of powder activators ($\text{Ca(OH)}_2 + \text{Na}_2\text{SO}_4$ vs $\text{Ca(OH)}_2 + \text{Na}_2\text{SiO}_3$) and w/b ratio on rheology, fiber dispersion, and mechanical properties.
Demonstrated tight crack width control with average residual crack width of 20.2 $\mu\text{m}$ at 28 days.

Evidence summary

Tensile strain capacity: $4.48 \pm 0.334\%$ for M1 (peak individual specimen 4.7%), $1.53\%$ for M2, $2.80\%$ for M3 (Table 7, page 17).
Tensile strength: $4.69 \pm 0.417\text{ MPa}$ for M1 (first crack strength $3.87\text{ MPa}$) (Table 7, page 17).
Compressive strength: $30.6 \pm 4.42\text{ MPa}$ for M1, $19.4\text{ MPa}$ for M2, $25.7\text{ MPa}$ for M3 (Table 6, page 17).
Crack characteristics: Average residual crack width of 20.2 $\mu\text{m}$ and crack spacing of 2–3 mm in M1 (Section 3.3, page 17).

Linked Atlas nodes

04_material_systems/green_ecc.md
02_concepts/strain_hardening_criteria.md
02_concepts/sustainability.md
05_experiments/direct_tensile_test.md

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`04_material_systems/green_ecc.md`	Cementless alkali-activated slag mortar reinforced with 2.0 vol% PVA fiber achieves direct tensile strain capacity up to 4.7% (mean 4.48%).	Tensile strain capacity of M1 reached 4.48% (peak 4.7%), 224 times that of plain matrix.	Page 15, Abstract; Page 17, Table 7, Fig. 3	verified_from_pdf
`04_material_systems/green_ecc.md`	Optimal AAS-PVA composite maintains tight residual microcracks averaging 20.2 $\mu\text{m}$ at 28 days.	Residual crack width averaged 20.2 $\mu\text{m}$ with multiple crack spacing of 2–3 mm.	Page 17, Section 3.3, Fig. 4	verified_from_pdf

Verification status

PDF preserved: yes (lee-2012-strain-hardening-fiber-reinforced-alkali-activated.pdf)
Text extracted: yes (atlas/full_text/lee-2012-strain-hardening-fiber-reinforced-alkali-activated_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2012.06.007)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

Moderate compressive strength (19.4–30.6 MPa) under ambient water curing.
Single-fiber pullout and fracture toughness were evaluated in later follow-up studies.