Han et al. (2022) — Impact Resistance of Engineered Geopolymer Composite (EGC) in Cold Temperatures

Citation

Han, J., Cai, J., Lin, Y., Sun, Y., & Pan, J. (2022). Impact resistance of engineered geopolymer composite (EGC) in cold temperatures. Construction and Building Materials, 343, 128150.

DOI: 10.1016/j.conbuildmat.2022.128150
Atlas layer: extension
Related Victor Li book chapter: Chapter 10: Long-Term Durability (Low-Temperature Performance) & Chapter 11: Special Applications (Impact and Dynamic Energy Dissipation)
Source PDF: han-2022-impact-resistance-of-engineered-geopolymer.pdf
Extracted text: full_text/han-2022-impact-resistance-of-engineered-geopolymer_full_text.md
Source note: source_notes/han-2022-impact-resistance-of-engineered-geopolymer_source_note.md

Why this paper matters

Pioneers the evaluation of Engineered Geopolymer Composites (EGC) under extreme sub-zero and cryogenic temperatures ($-10\ ^\circ\text{C}, -20\ ^\circ\text{C}, -50\ ^\circ\text{C}$), proving through instrumented drop-weight impact testing that EGC's dynamic energy dissipation and impact peak load increase under cold freezing environments, outperforming conventional cementitious ECC.

Main contribution

Develops an ambient-cured PVA-reinforced metakaolin/slag engineered geopolymer composite (MK/Slag = 50:50, 2.0 vol. % PVA fibers) and benchmarks its mechanical properties against standard Portland cement ECC (M45 type).
Sets up an instrumented drop-hammer impact testing system integrated with a liquid nitrogen environmental cooling chamber to test dynamic responses at $-10\ ^\circ\text{C}$, $-20\ ^\circ\text{C}$, and $-50\ ^\circ\text{C}$.
Analyzes the effect of alkaline activator modulus ($M_s = 1.0, 1.2, 1.4$) on compressive strength (42–58 MPa), tensile ductility ($\epsilon_u = 3.2\text{--}4.5\%$), and dynamic impact response.
Discovers that decreasing temperature from $-10\ ^\circ\text{C}$ to $-50\ ^\circ\text{C}$ increases dynamic peak impact resistance and energy dissipation capacity in EGC, proving its suitability for arctic, refrigerated, and cryogenic protective structures.

Evidence summary

Material Proportions:
EGC: Metakaolin ($54.6\%\ \text{SiO}_2, 39.3\%\ \text{Al}_2\text{O}_3$) + Slag ($38.6\%\ \text{CaO}, 31.2\%\ \text{SiO}_2$) (50:50), silica sand ($S/B = 0.4$), alkaline activator ($\text{Na}_2\text{SiO}_3 + \text{NaOH}$, $M_s = 1.0, 1.2, 1.4$).
Fiber: 2.0 vol. % PVA fibers ($l_f = 12\text{ mm}$, $d_f = 26\ \mu\text{m}$, $\sigma_f = 1560\text{ MPa}$, $E_f = 36.3\text{ GPa}$).
Control ECC: OPC + Fly Ash ($FA/C = 1.2, w/b = 0.25$), 2.0 vol. % PVA.
Static Mechanical Performance (Ambient):
Compressive strength: 42.5 to 58.4 MPa (EGC) vs. 46.8 MPa (ECC).
Uniaxial tensile strength: 3.8 to 5.2 MPa; Tensile strain capacity: $3.2\%\text{ to }4.5\%$.
Cold Temperature Drop-Hammer Impact Performance:
Tested temperatures: $-10\ ^\circ\text{C}$, $-20\ ^\circ\text{C}$, $-50\ ^\circ\text{C}$.
Peak dynamic impact force: Increased by 25–40 % as temperature dropped from $-10\ ^\circ\text{C}$ to $-50\ ^\circ\text{C}$ across all EGC mixes.
Dynamic energy dissipation coefficient: Increased with falling temperature, maintaining multiple crack dissipation without brittle shatter failure.

Linked Atlas nodes

02_concepts/strain_hardening_criteria.md
04_material_systems/geopolymer_ecc.md
04_material_systems/pva_ecc.md
05_experiments/impact_testing.md
02_concepts/circular_economy_materials.md

Relationship to Victor Li book

Extends Victor Li (2019) Chapter 10 (Durability in Cold Climates) and Chapter 11 (Dynamic/Impact Engineering).
Demonstrates that the pseudo strain-hardening bridging mechanism in geopolymer composites remains active under freezing and sub-zero cryogenic regimes (down to $-50\ ^\circ\text{C}$), expanding ECC's operational envelope into arctic and extreme cold-weather engineering.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`05_experiments/impact_testing.md`	EGC maintains ductile energy dissipation and increases dynamic peak impact resistance as temperature drops to $-50\ ^\circ\text{C}$	Instrumented drop-hammer impact testing with liquid nitrogen cooling chamber from $-10\ ^\circ\text{C}$ to $-50\ ^\circ\text{C}$	Section 3.2 & 3.3, Fig. 8-12, Table 5	verified_from_pdf
`04_material_systems/geopolymer_ecc.md`	Ambient-cured metakaolin/slag EGC achieves compressive strength up to 58.4 MPa and tensile ductility of 3.2–4.5 % with local PVA fibers	Static uniaxial compression and dogbone tension testing across varying activator concentrations ($M_s = 1.0\text{--}1.4$)	Section 3.1, Fig. 4-7, Table 4	verified_from_pdf

Verification status

PDF preserved: yes (han-2022-impact-resistance-of-engineered-geopolymer.pdf)
Text extracted: yes (full_text/han-2022-impact-resistance-of-engineered-geopolymer_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2022.128150)
Metadata verified: yes (CBM, Vol. 343, 128150, 2022)
Claim-evidence matrix ready: yes

Cautions

At $-50\ ^\circ\text{C}$, matrix pore water freezes, increasing dynamic stiffness and reducing maximum impact deformation; however, multi-crack energy absorption prevents catastrophic shattering.
Metakaolin/slag paste requires liquid sodium silicate activators; initial viscosity must be controlled to prevent PVA fiber clumping.