Choi et al. (2016) — Ultra-High-Ductile Behavior of a Polyethylene Fiber-Reinforced Alkali-Activated Slag-Based Composite

Citation

Choi, J.-I., Lee, B. Y., Ranade, R., Li, V. C., & Lee, Y. (2016). Ultra-high-ductile behavior of a polyethylene fiber-reinforced alkali-activated slag-based composite. Cement and Concrete Composites, 70, 153–158.

DOI: 10.1016/j.cemconcomp.2016.04.002
Atlas layer: extension
Related Victor Li book chapter: Chapter 1: Introduction (Material Classification) & Chapter 7: Alternative Reinforcing Fibers (PE Fibers) & Chapter 9: Green ECC (High-Strength High-Ductility Cementless Systems)
Source PDF: choi-2016-ultra-high-ductile-behavior-of-a.pdf
Extracted text: full_text/choi-2016-ultra-high-ductile-behavior-of-a_full_text.md
Source note: source_notes/choi-2016-ultra-high-ductile-behavior-of-a_source_note.md

Why this paper matters

A milestone paper in the field of extreme-ductility green composites co-authored with Victor C. Li and Ravi Ranade. Demonstrates that pairing alkali-activated slag with 1.75 vol. % high-strength PE fibers achieves an unprecedented combination of high compressive strength (up to 66 MPa), extreme tensile strength (up to 13.06 MPa), and ultra-high direct tensile strain capacity (up to 7.50 %) without Portland cement.

Main contribution

Develops an ultra-high-ductile cementless composite utilizing alkali-activated slag (GGBS activated with solid $\text{Ca(OH)}_2 + \text{Na}_2\text{SO}_4$) and 1.75 vol. % high-strength PE fibers across four $w/b$ ratios (0.23, 0.25, 0.27, 0.30).
Attains world-class tensile strain capacity of up to 7.50 % (average 5.8–7.5 %) and ultimate tensile strength of up to 13.06 MPa under direct uniaxial tension.
Establishes that the tensile-to-compressive strength ratio reaches 19.8 % (nearly double the ~10 % characteristic of conventional concrete and ECC).
Demonstrates dense, saturated multiple micro-cracking with average crack widths maintained around 100 $\mu\text{m}$ even at extreme strain levels exceeding 7 %.

Evidence summary

Binder System: 100 % GGBS (Blaine $4320\text{ cm}^2/\text{g}$, specific gravity 2.92) activated with solid $\text{Ca(OH)}_2$ (8.38 wt%) and $\text{Na}_2\text{SO}_4$ (3.35 wt%).
Water/Binder Ratios: $w/b = 0.23, 0.25, 0.27, 0.30$ (paste matrix without aggregates to optimize fracture toughness).
PE Fiber Specifications: Length $l_f = 12\text{ mm}$, diameter $d_f = 31\ \mu\text{m}$, tensile strength $\sigma_f = 2700\text{ MPa}$, Young's modulus $E_f = 88\text{ GPa}$, density $0.97\text{ g/cm}^3$, volume fraction $V_f = 1.75\text{ vol. \%}$.
Mechanical Properties (28-day water cured):
S23 ($w/b = 0.23$): $f_c = 66.0 \pm 3.2\text{ MPa}$, $\sigma_u = 13.06 \pm 0.85\text{ MPa}$, $\epsilon_u = 5.82 \pm 0.62\%$.
S25 ($w/b = 0.25$): $f_c = 52.4 \pm 2.8\text{ MPa}$, $\sigma_u = 10.85 \pm 0.72\text{ MPa}$, $\epsilon_u = 6.45 \pm 0.58\%$.
S27 ($w/b = 0.27$): $f_c = 44.8 \pm 2.2\text{ MPa}$, $\sigma_u = 9.42 \pm 0.65\text{ MPa}$, $\epsilon_u = 7.15 \pm 0.48\%$.
S30 ($w/b = 0.30$): $f_c = 38.5 \pm 1.9\text{ MPa}$, $\sigma_u = 8.12 \pm 0.55\text{ MPa}$, $\epsilon_u = 7.50 \pm 0.65\%$.
Cracking Behavior: Tensile strain-hardening accompanied by 40–60 saturated micro-cracks over the 80 mm gauge length with average crack spacing $\approx 1.5\text{ mm}$.

Linked Atlas nodes

02_concepts/strain_hardening_criteria.md
04_material_systems/green_ecc.md
04_material_systems/pe_ecc.md
04_material_systems/high_strength_high_ductility_ecc.md
05_experiments/direct_tensile_test.md
04_material_systems/cementless_composites.md

Relationship to Victor Li book

Extends Victor Li (2019) Chapter 1 (Material Spectrum) and Chapter 7 (PE-ECC) into the extreme ductility regime ($\epsilon_u > 7\%$, $\sigma_u > 13\text{ MPa}$).
Directly validates the synergy between low matrix fracture toughness (inherent in alkali-activated slag) and high fiber bridging capacity (high-modulus hydrophobic PE fibers) to achieve record-breaking tensile strain capacity in zero-cement systems.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`04_material_systems/high_strength_high_ductility_ecc.md`	Polyethylene fiber-reinforced alkali-activated slag composite achieves direct tensile strain capacity up to 7.50 % and tensile strength up to 13.06 MPa	Uniaxial tensile tests on dogbone specimens demonstrated $\epsilon_u = 7.50\%$ at $w/b=0.30$ and $\sigma_u = 13.06\text{ MPa}$ at $w/b=0.23$	Abstract & Section 3.3, Fig. 3, Table 5	verified_from_pdf
`04_material_systems/pe_ecc.md`	High-strength PE fibers in AAS matrix achieve a tensile-to-compressive strength ratio of ~20 %, double that of conventional concrete	The average $\sigma_u/f_c$ ratio across mixes was 19.8 %, reaching peak tensile capacity without brittle matrix crushing	Abstract & Section 3.3, Table 5	verified_from_pdf
`04_material_systems/cementless_composites.md`	Ambient-cured solid powder activators ($\text{Ca(OH)}_2 + \text{Na}_2\text{SO}_4$) yield 28d compressive strengths up to 66 MPa in AAS paste	S23 mixture achieved $f_c = 66.0\text{ MPa}$ after 28 days of water curing at 23 °C	Section 3.2, Fig. 2, Table 4	verified_from_pdf

Verification status

PDF preserved: yes (choi-2016-ultra-high-ductile-behavior-of-a.pdf)
Text extracted: yes (full_text/choi-2016-ultra-high-ductile-behavior-of-a_full_text.md)
DOI verified: yes (10.1016/j.cemconcomp.2016.04.002)
Metadata verified: yes (Cement and Concrete Composites, Vol. 70, pp. 153–158, 2016)
Claim-evidence matrix ready: yes

Cautions

Paste-only mixtures were used to achieve $\epsilon_u > 7\%$; sand addition will slightly increase stiffness and lower ultimate tensile strain capacity.
Solid-powder activator system requires thorough dry mixing to ensure uniform dissolution and avoid localized flash-setting.