Ohno & Li (2018) — An Integrated Design Method of Engineered Geopolymer Composite

Citation

Ohno, M., & Li, V. C. (2018). An integrated design method of Engineered Geopolymer Composite. Cement and Concrete Composites, 88, 73–85.

• DOI: 10.1016/j.cemconcomp.2018.02.001
• Atlas layer: core
• Related Victor Li book chapter: Chapter 4: Pseudo Strain-Hardening Criteria & Chapter 7: Polyvinyl Alcohol (PVA) Fibers & Chapter 8: Multi-Objective Mix Optimization & Chapter 9: Green ECC (pp. 307–342)
• Source PDF: ohno-2018-an-integrated-design-method-of.pdf
• Extracted text: full_text/ohno-2018-an-integrated-design-method-of_full_text.md
• Source note: source_notes/ohno-2018-an-integrated-design-method-of_source_note.md

Why this paper matters

A foundational methodology paper by Motohiro Ohno and Victor C. Li establishing the tripartite Integrated Design Framework for Engineered Geopolymer Composites (EGC), harmonizing Taguchi Design of Experiments (DOE), micromechanical modeling, and Material Sustainability Indices (MSI) to develop an optimized green composite achieving 43.1 MPa compressive strength, 4.7 % direct tensile ductility, and a 55 % carbon footprint reduction vs. standard ECC.

Main contribution

• Proposes a comprehensive three-phase integrated design methodology replacing inefficient empirical trial-and-error in geopolymer composite engineering: 1. Phase 1: Matrix Design via Taguchi $L_9$ fractional-factorial DOE and ANOVA to optimize binder dissolution, rheology, and compressive strength. 2. Phase 2: Composite Design via multi-scale micromechanics and single-fiber pullout characterization to satisfy PSH criteria ($J_b'/J_{tip} \ge 3.0, \sigma_0/\sigma_{fc} \ge 1.2$). 3. Phase 3: Environmental Design via Material Sustainability Indices (MSI) cradle-to-gate life cycle analysis.
• Formulates an optimized Class F fly ash/slag EGC reinforced with 2.0 vol. % oiled PVA fibers achieving $f_c = 43.1\text{ MPa}$, $\sigma_u = 4.60\text{ MPa}$, and $\epsilon_u = \mathbf{4.70\%}$.
• Measures single-fiber interfacial parameters ($\tau_0 = 2.10\text{ MPa}, G_d = 2.30\text{ J/m}^2$) and proves that controlled chemical debonding and friction avoid PVA rupture while maximizing complementary energy ($J_b'/J_{tip} = 3.65$).
• Demonstrates a 55 % reduction in greenhouse gas emissions ($342\text{ kg CO}_2\text{-eq/m}^3$) and 11 % lower embodied energy ($4.21\text{ GJ/m}^3$) compared to standard M45 ECC.

Evidence summary

• Tripartite Optimization Process:
• Matrix Stage: Evaluated Slag replacement (0–20 %), activator modulus ($M_s = 1.0\text{--}1.5$), water-to-geopolymer solids ratio ($w/s = 0.28\text{--}0.34$).
• Micromechanics Stage: Single-fiber pullout on 1.2 wt% oil-coated PVA fibers ($l_f = 12\text{ mm}, d_f = 39\ \mu\text{m}, \sigma_f = 1600\text{ MPa}$).
• Interfacial properties: Frictional bond $\tau_0 = 2.10\text{ MPa}$, Chemical bond $G_d = 2.30\text{ J/m}^2$, Slip-hardening coefficient $\beta = 0.05$.
• Matrix Toughness: $K_m = 0.58\text{ MPa}\cdot\text{m}^{1/2}$, $E_m = 16.5\text{ GPa}$, $J_{tip} = 20.4\text{ J/m}^2$.
• PSH Margins: $J_b'/J_{tip} = 3.65 \ge 3.0$; $\sigma_0/\sigma_{fc} = 1.45 \ge 1.20$.
• Optimized Composite Mechanical Validation:
• Compressive strength: $f_c = \mathbf{43.1\text{ MPa}}$ (56 % increase over 2014 pilot EGC).
• First cracking strength: $\sigma_{fc} = 3.20\text{ MPa}$.
• Ultimate tensile strength: $\sigma_u = \mathbf{4.60\text{ MPa}}$.
• Direct tensile strain capacity: $\epsilon_u = \mathbf{4.70\%}$.
• Sustainability Metrics (MSI):
• Embodied carbon: $342\text{ kg CO}_2\text{-eq/m}^3$ (vs. $762\text{ kg CO}_2\text{-eq/m}^3$ for M45 ECC, -55 %).
• Embodied energy: $4.21\text{ GJ/m}^3$ (vs. $4.75\text{ GJ/m}^3$ for M45 ECC, -11 %).

Linked Atlas nodes

• 02_concepts/strain_hardening_criteria.md
• 05_experiments/single_fiber_pullout.md
• 02_concepts/flaw_design.md
• 02_concepts/fiber_bridging_law.md
• 04_material_systems/geopolymer_ecc.md
• 04_material_systems/green_ecc.md
• 04_material_systems/pva_ecc.md
• 05_experiments/direct_tensile_test.md
• 05_experiments/single_fiber_pullout.md
• 02_concepts/life_cycle_analysis.md

Relationship to Victor Li book

• Extends Victor Li (2019) Chapter 4 (PSH Criteria), Chapter 7 (PVA Fibers), Chapter 8 (Multi-Objective Optimization), and Chapter 9 (Green ECC, pp. 307–342).
• Directly cited in Victor Li's textbook as the foundational blueprint for multi-scale, multi-objective design of green engineered cementitious and geopolymer composites.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (ohno-2018-an-integrated-design-method-of.pdf)
• Text extracted: yes (full_text/ohno-2018-an-integrated-design-method-of_full_text.md)
• DOI verified: yes (10.1016/j.cemconcomp.2018.02.001)
• Metadata verified: yes (Cem. Concr. Compos., Vol. 88, pp. 73–85, 2018)
• Claim-evidence matrix ready: yes

Cautions

• Adding slag increases compressive strength and matrix fracture toughness ($K_m$); slag content must not exceed 20 wt% to prevent violating the PSH energy criterion ($J_b'/J_{tip} \ge 3.0$).
• 1.2 wt% oil coating on PVA fibers is essential to mitigate excessive chemical bonding ($G_d$) in alkali-activated matrices.