Kwon et al. (2018) — Tensile Strain-Hardening of Slag-Based Composites (PP vs PE vs PBO)
Citation
Seung-Jun Kwon, Jeong-Il Choi, Huy Hoàng Nguyễn, Bang Yeon Lee (2018). Tensile strain-hardening behaviors and crack patterns of slag-based fiber-reinforced composites. Computers and Concrete, 21(3), 231–237.
- DOI:
10.12989/cac.2018.21.3.231 - Atlas layer: supporting
- Related Victor Li book chapter: Chapter 4: Micromechanics-Based Material Design (also Chapter 9)
- Source PDF:
primary_data/kwon-2018-tensile-strain-hardening-behaviors-and-crack.pdfIJP04118E_Tensile strain-hardening_CAC.pdf` - Extracted text:
secondary_data/full_texts/kwon-2018-tensile-strain-hardening-behaviors-and-crack_full_text.mdsecondary_data/full_texts/IJP04118E_Tensile strain-hardening_CAC_full_text.md` - Source note:
secondary_data/source_notes/kwon-2018-tensile-strain-hardening-behaviors-and-crack_source_note.mdsecondary_data/source_notes/IJP04118E_Tensile strain-hardening_CAC_source_note.md`
Why this paper matters
Provides a direct experimental comparison of polypropylene (PP), polyethylene (PE), and polyparaphenylene-benzobisoxazole (PBO) fibers (1.75 vol. %) in alkali-activated slag (AAS) composites across multiple $w/b$ ratios (0.35, 0.45, 0.55), proving that PE fibers maximize tensile ductility ($\epsilon_u = 4.93\text{ \%}$) while PBO fibers achieve the highest tensile strength (5.75 MPa) and ultra-tight crack widths (17.2 $\mu\text{m}$).
Main contribution
- Fiber Type Performance Benchmark: Evaluated nine mixture combinations in 100 % cementless slag matrix, showing that PE fibers achieve $4.93 \pm 0.45\text{ \%}$ tensile strain capacity compared to PP ($1.94 \sim 3.00\text{ \%}$) and untreated PBO ($0.99 \sim 1.86\text{ \%}$).
- Ultra-Fine Crack Control with PBO: PBO fibers ($E_f = 180\text{ GPa}, \sigma_{fu} = 5800\text{ MPa}$) compressed average crack width to $17.2\ \mu\text{m}$ (80 % narrower than PE) and crack spacing to $0.86\text{ mm}$.
- Stress Performance Index Validation: Proved that the stress ratio $\sigma_u/\sigma_{fc} = 2.27$ in PE-0.35 governs multiple micro-cracking saturation.
Evidence summary
- Direct Tensile Response:
PE-0.35: $\epsilon_u = 4.93\text{ \%}$, $\sigma_{tu} = 4.82\text{ MPa}$, $\sigma_{fc} = 2.12\text{ MPa}$ (Table 5–7, Page 234).PBO-0.35: $\epsilon_u = 1.86\text{ \%}$, $\sigma_{tu} = 5.75\text{ MPa}$ (highest strength), $\sigma_{fc} = 3.81\text{ MPa}$.PP-0.35: $\epsilon_u = 1.94\text{ \%}$, $\sigma_{tu} = 3.24\text{ MPa}$, $\sigma_{fc} = 2.91\text{ MPa}$.- Compressive Strength: $36.8 \sim 40.1\text{ MPa}$ at $w/b=0.35$; $19.7 \sim 24.0\text{ MPa}$ at $w/b=0.45$; $8.8 \sim 11.8\text{ MPa}$ at $w/b=0.55$ (Table 4, Page 233).
- Crack Characteristics: PBO crack width = $17.2\ \mu\text{m}$ (spacing 0.86 mm); PE crack width = $85.4\ \mu\text{m}$ (spacing 2.1 mm); PP crack width = $144.6\ \mu\text{m}$ (spacing 10.3 mm) (Figs. 6–8, Pages 235–236).
Linked Atlas nodes
04_material_systems/green_ecc.md02_concepts/strain_hardening_criteria.md05_experiments/crack_width_distribution.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).
- Directly supports Chapter 4 (Fiber Selection) and Chapter 9 (Green ECC) by verifying that fiber modulus and interfacial chemical bonding govern the trade-off between ultra-tight crack width and maximum tensile strain capacity.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/green_ecc.md |
PE fiber reinforcement in alkali-activated slag matrix achieves 4.93 % tensile strain capacity at $w/b=0.35$ | PE-0.35 mix attained $\epsilon_u = 4.93\text{ \%}$ and $\sigma_{tu} = 4.82\text{ MPa}$ in uniaxial tension | Page 231 & 234 / Table 7 / Fig. 2 | verified_from_pdf |
05_experiments/crack_width_distribution.md |
High-modulus PBO fibers reduce crack width to 17.2 $\mu\text{m}$ (80 % tighter than PE) in slag-based composites | PBO-0.35 achieved an average crack width of $17.2\ \mu\text{m}$ and crack spacing of $0.86\text{ mm}$ | Page 236 / Fig. 7 & Fig. 8 | verified_from_pdf |
02_concepts/strain_hardening_criteria.md |
Excessive chemical bond in PBO fibers limits tensile strain capacity to 1.86 % despite 5800 MPa nominal fiber strength | PBO tensile strain capacity was 70 % lower than PE due to strong interfacial bond and high modulus | Page 234 / Section 3.2 | Table 2 & Table 7 |
Verification status
- PDF preserved: yes (in
primary_data/IJP04118E_Tensile strain-hardening_CAC.pdf) - Text extracted: yes (PyMuPDF, 7 pages)
- DOI verified: yes (
10.12989/cac.2018.21.3.231) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- Untreated PBO fibers showed lower tensile ductility (1.86 %) due to unmitigated chemical bonding; surface oiling is recommended.