Elmesalami & Celik (2022) — A Critical Review of Engineered Geopolymer Composite: A Low-Carbon Ultra-High-Performance Concrete

Citation

Elmesalami, N., & Celik, K. (2022). A critical review of engineered geopolymer composite: A low-carbon ultra-high-performance concrete. Construction and Building Materials, 346, 128491.

DOI: 10.1016/j.conbuildmat.2022.128491
Atlas layer: review
Related Victor Li book chapter: Chapter 4: Pseudo Strain-Hardening Criteria & Chapter 7: Alternative Fibers & Chapter 9: Green ECC (Engineered Geopolymer Composites)
Source PDF: elmesalami-2022-a-critical-review-of-engineered.pdf
Extracted text: full_text/elmesalami-2022-a-critical-review-of-engineered_full_text.md
Source note: source_notes/elmesalami-2022-a-critical-review-of-engineered_source_note.md

Why this paper matters

Provides the most comprehensive and systematic review on Engineered Geopolymer Composites (EGC/SHGC) to date, synthesizing global datasets on precursor chemistries, fiber types (PVA, PE, PP, PBO, steel), micromechanical tailoring indices ($J_b'/J_{tip}$ and $\sigma_0/\sigma_{fc}$), ambient vs. heat curing, self-healing, and environmental life cycle benefits.

Main contribution

Performs scientometric mapping and comprehensive literature synthesis of over a decade of research on Engineered Geopolymer Composites (EGC) and Strain-Hardening Geopolymer Composites (SHGC).
Conducts rigorous micromechanical comparisons between traditional cement-based ECC and geopolymer EGC, contrasting matrix fracture toughness ($K_m$), chemical debond energy ($G_d$), and interfacial friction ($\tau_0, \beta$).
Categorizes precursor systems (fly ash Class F, GGBFS slag, metakaolin, rice husk ash, red mud) and activator systems (two-part liquid $\text{NaOH}/\text{Na}_2\text{SiO}_3$ vs. one-part solid powder activators).
Evaluates the trade-offs across fiber types: PE fibers deliver extreme ductility ($\epsilon_u$ up to 8–10 %) and high tensile strength ($\sigma_u > 10\text{ MPa}$), whereas PVA fibers require precise interface control to prevent rupture in high-alkalinity matrices.
Synthesizes life cycle assessment (LCA) data, demonstrating that EGC can reduce cradle-to-gate CO2 emissions by up to 70–80 % compared to standard Portland cement ECC.

Evidence summary

Precursor & Activator Categorization:
Fly Ash systems: High ambient setting time; typically requires $60\text{--}80\ ^\circ\text{C}$ heat curing or slag blending (20–50 %) for ambient activation.
Slag (GGBFS) systems: Rapid room-temperature strength development ($f_c = 30\text{--}70\text{ MPa}$), lower $K_m$ than OPC paste.
Micromechanical Parameter Benchmarks in EGC:
Matrix toughness: $K_m = 0.25\text{--}0.60\text{ MPa}\cdot\text{m}^{1/2}$ (lower than OPC concrete, favorable for PSH).
PVA-EGC: Chemical bond $G_d = 2.0\text{--}5.5\text{ J/m}^2$, $\tau_0 = 1.5\text{--}4.0\text{ MPa}$; requires oil coating to prevent fiber rupture.
PE-EGC: $G_d \approx 0\text{ J/m}^2$, $\tau_0 = 1.0\text{--}2.5\text{ MPa}$, $\beta = 0.05\text{--}0.15$; achieves $J_b'/J_{tip} > 10$ and $\epsilon_u = 4\text{--}10\%$.
Sustainability Metrics: EGC reduces embodied carbon by 50–80 % compared to M45 ECC, though alkali activator synthesis ($\text{Na}_2\text{SiO}_3$) represents 60–80 % of EGC's remaining carbon footprint.

Linked Atlas nodes

02_concepts/strain_hardening_criteria.md
04_material_systems/geopolymer_ecc.md
04_material_systems/green_ecc.md
04_material_systems/pe_ecc.md
04_material_systems/pva_ecc.md
02_concepts/life_cycle_analysis.md

Relationship to Victor Li book

Systematically reviews the transition from Victor Li (2019) Chapter 9 (Green ECC) into full-scale 100 % cementless geopolymer composites.
Confirms that Victor Li's PSH micromechanical framework ($J_b'/J_{tip} \ge 3$, $\sigma_0/\sigma_{fc} \ge 1.2$) remains the foundational governing law across all alkali-activated aluminosilicate binder matrices.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`04_material_systems/geopolymer_ecc.md`	EGC systems achieve tensile strain capacities between 2 % and 10 % while reducing binder embodied carbon by up to 80 %	Comprehensive meta-analysis of over 80 experimental EGC studies across fly ash, slag, and metakaolin binders	Section 4 & 7, Fig. 6-12, Table 2-4	verified_from_pdf
`02_concepts/strain_hardening_criteria.md`	Lower matrix fracture toughness ($K_m \approx 0.3\text{--}0.5\text{ MPa}\cdot\text{m}^{1/2}$) in geopolymer matrices expands the PSH energy margin for synthetic fibers	Comparative review of micromechanical parameters between OPC-ECC and alkali-activated EGC	Section 3.2, Table 1	verified_from_pdf
`02_concepts/life_cycle_analysis.md`	Sodium silicate and sodium hydroxide activators account for 60–80 % of total embodied carbon in traditional two-part EGC	LCA data synthesis identifying activator production as the dominant carbon hotspot in geopolymer composites	Section 7.3, Fig. 18	verified_from_pdf

Verification status

PDF preserved: yes (elmesalami-2022-a-critical-review-of-engineered.pdf)
Text extracted: yes (full_text/elmesalami-2022-a-critical-review-of-engineered_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2022.128491)
Metadata verified: yes (CBM, Vol. 346, 128491, 2022)
Claim-evidence matrix ready: yes

Cautions

Review article aggregating diverse experimental standards, specimen geometries (JSCE dumbbell vs. ASTM dogbone vs. coupon plates), and curing methods.
Highlights that two-part liquid alkali activators present safety and carbon burdens, identifying one-part "just-add-water" solid activators as the critical future research need.