Lương et al. (2025) — Ultra-Ductility Exceeding 13 % with Rubberized Alkali-Activated Slag Composites

Citation

Quang-Hiếu Lương, Huy Hoàng Nguyễn, Phương Hoàng Nguyễn, Se-Eon Park, Youngsang Kim, Bang Yeon Lee (2025). Achieving ultra-ductility exceeding 13 % and cost efficiency with rubberized alkali-activated slag-based cement-free composites. Developments in the Built Environment, 22, 100677.

• DOI: 10.1016/j.dibe.2025.100677
• Atlas layer: extension
• Related Victor Li book chapter: Chapter 9: Green ECC & Chapter 4: Micromechanics-Based Material Design
• Source PDF: primary_data/luong-2025-achieving-ultra-ductility-exceeding-13.pdfIJP08325E_Achieving ultra-ductility exceeding 13_DIBE.pdf`
• Extracted text: secondary_data/full_texts/luong-2025-achieving-ultra-ductility-exceeding-13_full_text.mdsecondary_data/full_texts/IJP08325E_Achieving ultra-ductility exceeding 13_DIBE_full_text.md`
• Source note: secondary_data/source_notes/luong-2025-achieving-ultra-ductility-exceeding-13_source_note.mdsecondary_data/source_notes/IJP08325E_Achieving ultra-ductility exceeding 13_DIBE_source_note.md`

Why this paper matters

Develops ultra-ductile rubberized alkali-activated slag composites (UD-RSC: 100 % cementless GGBS activated by 10 wt% $\text{Ca(OH)}_2$ with 5 wt% crumb rubber), demonstrating that virgin PE reinforcement with high sand content ($s/b = 0.8$) achieves a direct tensile strain capacity of $15.64 \pm 1.83\text{ \%}$ (surpassing rebar extensibility), while recycled PE-selvage fiber composite (SPE25-S4) delivers $37.0\text{ MPa}$ compressive strength, $6.36\text{ MPa}$ tensile strength, and $13.41 \pm 1.30\text{ \%}$ tensile strain capacity at a low material cost of approximately $300\text{ \$/m}^3$, achieving the highest Performance-Cost Index (PCI).

Main contribution

• Ductility Exceeding Rebar Extensibility: 15.64 %: High-sand virgin PE composite (PE30-S8, $s/b = 0.8, w/b = 0.30$) achieved $15.64 \pm 1.83\text{ \%}$ direct tensile strain capacity with $f_c = 34.8\text{ MPa}$ and $\sigma_{tu} = 5.33\text{ MPa}$.
• 13.41 % Ultra-Ductility with Recycled Selvage Fibers: Recycled selvage PE composite (SPE25-S4, $s/b = 0.4, w/b = 0.25$) achieved $37.0\text{ MPa}$ compressive strength, $6.36 \pm 0.65\text{ MPa}$ tensile strength, and $13.41 \pm 1.30\text{ \%}$ tensile strain capacity ($\text{CoV} = 9.7\text{ \%}$).
• Highest Performance-Cost Index (PCI): Slashed material cost to $300\text{ \$/m}^3$ (2–3x normal concrete vs 6x for virgin PE-ECC) while maximizing mechanical efficiency.
• Mineralogical Identification of C-A-S-H Gel: EDS ternary phase diagram confirmed C-A-S-H gel as the primary hydration product.

Evidence summary

• Compressive Strength & Density:
• PE30-S0: $f_c = 27.5\text{ MPa}$, $\rho = 1.63\text{ g/cm}^3$ (Fig. 5, Page 3).
• PE30-S4: $f_c = 33.1\text{ MPa}$, $\rho = 1.77\text{ g/cm}^3$.
• PE30-S8: $f_c = \mathbf{34.8\text{ MPa}}$, $\rho = 1.88\text{ g/cm}^3$.
• PE25-S4: $f_c = 37.2\text{ MPa}$, $\rho = 1.83\text{ g/cm}^3$.
• SPE25-S4: $f_c = \mathbf{37.0\text{ MPa}}$, $\rho = 1.83\text{ g/cm}^3$.
• Direct Uniaxial Tensile Properties:
• PE30-S8: $\sigma_{1c} = 4.01 \pm 0.43\text{ MPa}$, $\sigma_{tu} = 5.33 \pm 0.50\text{ MPa}$, $\epsilon_{ts} = \mathbf{15.64 \pm 1.83\text{ \%}}$, $E_{ts} = 0.73\text{ MPa}\cdot\text{m/m}$, $f_t/f_c = 15.3\text{ \%}$ (Table 4 & Figs. 6–7, Pages 4–5).
• SPE25-S4: $\sigma_{1c} = 3.83 \pm 0.27\text{ MPa}$, $\sigma_{tu} = \mathbf{6.36 \pm 0.65\text{ MPa}}$, $\epsilon_{ts} = \mathbf{13.41 \pm 1.30\text{ \%}}$, $E_{ts} = 0.68\text{ MPa}\cdot\text{m/m}$, $f_t/f_c = 17.2\text{ \%}$.
• PE25-S4: $\sigma_{1c} = 3.54 \pm 0.37\text{ MPa}$, $\sigma_{tu} = 5.94 \pm 0.40\text{ MPa}$, $\epsilon_{ts} = 14.61 \pm 2.29\text{ \%}$, $E_{ts} = 0.69\text{ MPa}\cdot\text{m/m}$.
• Cracking Patterns:
• PE30-S0: 119.0 cracks, $l_s = 0.68\text{ mm}$, $w_c = 82.5\ \mu\text{m}$ (Table 6, Page 5).
• PE30-S8: 57.2 cracks, $l_s = 1.44\text{ mm}$, $w_c = 223.3\ \mu\text{m}$.
• SPE25-S4: 46.1 cracks, $l_s = 1.83\text{ mm}$, $w_c = 239.8\ \mu\text{m}$.
• Performance-Cost Index & Mineralogy:
• SPE25-S4 achieved highest PCI value across all benchmarked composites at $300\text{ \$/m}^3$ (Figs. 9–10 & Table 7, Pages 6–8).
• SEM/EDS confirmed dominant fiber pullout and C-A-S-H gel (Figs. 11–12, Pages 9–10).

Linked Atlas nodes

• 04_material_systems/cementless_composites.md
• 04_material_systems/green_ecc.md
• 02_concepts/flaw_design.md
• 05_experiments/direct_tensile_test.md

Relationship to Victor Li book

• Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
• Directly extends Chapter 9 (Green ECC) and Chapter 4 (Micromechanics) by showing that combining 100 % cementless alkali-activated slag, crumb rubber, and high sand content ($s/b = 0.8$) delivers $15.64\text{ \%}$ direct tensile strain capacity (exceeding rebar ductility), while recycled selvage PE fibers achieve $13.41\text{ \%}$ ductility and $37.0\text{ MPa}$ strength at $300\text{ \$/m}^3$.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (in primary_data/IJP08325E_Achieving ultra-ductility exceeding 13_DIBE.pdf)
• Text extracted: yes (PyMuPDF, 12 pages)
• DOI verified: yes (10.1016/j.dibe.2025.100677)
• Page/figure/table verified: yes (all checked in PDF text)
• Claim-evidence matrix ready: yes

Cautions

• At extreme strains ($>13\text{ \%}$), crack widths expand to $223\text{--}240\ \mu\text{m}$.
• Setting retardations from high superplasticizer require 4-day demolding.