Nguyễn et al. (2026) — Ambient Temperature Curing Stimulated One-Part Engineered Geopolymer Composites with Extremely High Ductility and Low Thermal Conductivity
Citation
Nguyễn, P. H., Nguyễn, H. H., Lương, Q.-H., Kim, Y., & Lee, B. Y. (2026). Ambient temperature curing stimulated one-part engineered geopolymer composites with extremely high ductility and low thermal conductivity. Journal of Materials in Civil Engineering, 38(4), 04026063.
- DOI:
10.1061/JMCEE7.MTENG-22099 - Atlas layer: core
- Related Victor Li book chapter: Chapter 4: Matrix Flaw Size Tailoring (EPS Bead Inclusions) & Chapter 7: Alternative Reinforcing Fibers (PE Fibers) & Chapter 9: Green Lightweight ECC (One-Part Geopolymers, pp. 307–342)
- Source PDF:
nguyn-2026-ambient-temperature-curing-stimulated-one-part.pdf - Extracted text:
full_text/nguyn-2026-ambient-temperature-curing-stimulated-one-part_full_text.md - Source note:
source_notes/nguyn-2026-ambient-temperature-curing-stimulated-one-part_source_note.md
Why this paper matters
A breakthrough ASCE journal study from Chonnam National University and Lehigh University developing ambient-cured "just-add-water" dry-mix One-Part EGC incorporating expanded polystyrene (EPS) beads, achieving an extraordinary direct tensile strain capacity of 20.9 % with only 1.2 vol. % PE fibers and low thermal conductivity ($0.58\text{ W/(m}\cdot\text{K)}$) under ambient air curing.
Main contribution
- Develops an ambient-cured One-Part "Just-Add-Water" dry-mix EGC combining Class F fly ash, GGBFS, solid anhydrous sodium metasilicate powder, 1.20 vol. % PE fibers, and expanded polystyrene (EPS) beads.
- Eliminates both user-hostile liquid activators and high-temperature thermal ovens, curing specimens under standard ambient room temperature ($23\ ^\circ\text{C}$).
- Discovers that incorporating 1–2 mm EPS beads creates low-stiffness artificial flaw nucleation sites that suppress matrix fracture toughness and unlock an astounding direct tensile strain capacity of 20.9 % (surpassing structural steel rebar extensibility).
- Achieves high tensile-to-compressive strength ratios ($\sigma_u/f_c = 18.1\%\text{--}24.5\%$, double that of concrete), lightweight density ($\rho < 1.87\text{ g/cm}^3$), and low thermal conductivity ($k = 0.58\text{ W/(m}\cdot\text{K)}$).
- Demonstrates extreme dynamic toughness, surviving $> 60$ repeated drop-weight projectile impact cycles.
Evidence summary
- One-Part Dry-Mix Formulation: Class F Fly Ash + GGBFS (50:50) with solid anhydrous sodium metasilicate powder, silica sand ($S/B = 0.36$), $w/b = 0.30$.
- Flaw Seeding: Expanded Polystyrene (EPS) beads (1–2 mm and 2–3 mm diameter at 0.05–0.10 volume fraction).
- Fiber Specifications: Low dosage 1.20 vol. % UHMWPE fibers ($l_f = 12\text{ mm}, d_f = 24\ \mu\text{m}, \sigma_f = 3000\text{ MPa}, E_f = 100\text{ GPa}$).
- Mechanical & Thermal Properties (Ambient Air Cured, 28 days):
- EPS 1–2 mm Mix: Compressive strength $f_c = 22.5\text{ MPa}$, Ultimate tensile strength $\sigma_u = 4.85\text{ MPa}$ ($\sigma_u/f_c = 21.6\%$), Direct tensile strain capacity $\epsilon_u = \mathbf{20.90\%}$, Thermal conductivity $k = \mathbf{0.58\text{ W/(m}\cdot\text{K)}}$.
- Control Mix (0 % EPS): Compressive strength $f_c = 44.2\text{ MPa}$, Ultimate tensile strength $\sigma_u = 5.20\text{ MPa}$, Direct tensile strain capacity $\epsilon_u = 4.50\%$, Thermal conductivity $k = 0.89\text{ W/(m}\cdot\text{K)}$.
- Impact Resistance: Survived $> 60$ consecutive drop-weight impact cycles with zero shattering.
- Mineralogy: SEM-EDS confirms the simultaneous formation of 3D N-A-S-H and C-(N)-A-S-H gel products.
Linked Atlas nodes
02_concepts/strain_hardening_criteria.md02_concepts/flaw_design.md04_material_systems/geopolymer_ecc.md04_material_systems/green_ecc.md04_material_systems/lightweight_ecc.md04_material_systems/pe_ecc.md05_experiments/direct_tensile_test.md04_material_systems/impact_resistant_structures.md
Relationship to Victor Li book
- Extends Victor Li (2019) Chapter 4 (Matrix Flaw Size Tailoring via EPS Inclusions), Chapter 7 (PE Fibers), and Chapter 9 (Green Lightweight ECC).
- Pushes the theoretical boundaries of PSH in one-part "just-add-water" geopolymers: proves that seeding lightweight EPS beads artificially creates a saturated steady-state crack spectrum, enabling the composite to maintain strain-hardening past 20 % strain with only 1.2 vol. % fiber content.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
04_material_systems/pe_ecc.md |
Ambient-cured one-part dry-mix EPS-EGC achieves 20.9 % direct tensile strain capacity with only 1.2 vol. % PE fibers | JSCE uniaxial direct tensile dogbone tests under ambient air curing | Section 3.1 & 3.2, Fig. 4-7, Table 2 | verified_from_pdf |
04_material_systems/lightweight_ecc.md |
Incorporating EPS beads into one-part EGC reduces thermal conductivity to $0.58\text{ W/(m}\cdot\text{K)}$ and density $< 1.87\text{ g/cm}^3$ | Transient plane source thermal testing and density measurements | Section 3.3 & 3.4, Fig. 8 & 9, Table 3 | verified_from_pdf |
Verification status
- PDF preserved: yes (
nguyn-2026-ambient-temperature-curing-stimulated-one-part.pdf) - Text extracted: yes (
full_text/nguyn-2026-ambient-temperature-curing-stimulated-one-part_full_text.md) - DOI verified: yes (
10.1061/JMCEE7.MTENG-22099) - Metadata verified: yes (J. Mater. Civ. Eng., Vol. 38, Art. 04026063, 2026)
- Claim-evidence matrix ready: yes
Cautions
- EPS beads have negligible compressive strength, reducing composite $f_c$ from 44.2 MPa to 22.5 MPa; structural applications must balance insulation and strength requirements.
- Hydrophobic EPS beads require calibrated mixing procedures to avoid dry bead agglomeration or buoyant floating segregation during casting.