Li (2016) — Bendable Concrete (CIC Innovation Award International Grand Prize Monograph)

Citation

Li, V. C. (2016). Bendable concrete. Innovation in Construction (iCON), Special Issue: CIC Research Journal 2016 (International Grand Prize, CIC Innovation Award 2015), Construction Industry Council, Hong Kong, 10–17. ISSN: 2312-8291.

Atlas layer: core
Related Victor Li book chapter: Chapter 1: Introduction to ECC & Chapter 4: PSH Criteria & Chapter 10: Durability & Chapter 11: Infrastructure Applications
Source PDF: li-2016-bendable-concrete.pdf
Extracted text: full_text/li-2016-bendable-concrete_full_text.md
Source note: source_notes/li-2016-bendable-concrete_source_note.md

Why this paper matters

The official CIC Innovation Award International Grand Prize monograph by Prof. Victor C. Li providing a definitive, holistic overview of Bendable Concrete (ECC) technology—from micromechanical energy/strength design principles to material durability, autogenous self-healing, and landmark full-scale infrastructure deployments worldwide.

Main contribution

Summarizes the foundational micromechanical design philosophy of ECC that systematically decouples ductility from fiber volume fraction through steady-state flat crack propagation criteria.
Defines core benchmark properties: 2–5 % tensile ductility (300–500 times that of conventional concrete), compressive strength of 40–80 MPa, and self-controlled microcrack widths ($< 100\ \mu\text{m}$, typically $60\ \mu\text{m}$).
Demonstrates extreme damage tolerance under severe reverse cyclic shear, high-velocity projectile impact, and seismic ground motions.
Highlights autogenous self-healing mechanisms where micro-cracks under $50\ \mu\text{m}$ completely seal via calcium carbonate precipitation upon contact with ambient moisture and carbon dioxide.
Synthesizes global full-scale field implementations: jointless bridge deck link slabs (Mihara Bridge, Grove Street Bridge), high-rise seismic core damper walls (Tokyo), tunnel linings, and water retaining structure retrofits.

Evidence summary

Micromechanical Criteria:
Energy criterion: $J_b' / J_{tip} \ge 3.0$
Strength criterion: $\sigma_0 / \sigma_{fc} \ge 1.20$
Typical Standard ECC Properties (M45):
Fiber: 2.0 vol. % oiled PVA fibers ($l_f = 12\text{ mm}, d_f = 39\ \mu\text{m}, \sigma_f = 1600\text{ MPa}$).
Compressive strength ($f_c$): 40 to 70 MPa.
Direct tensile strain capacity ($\epsilon_u$): 3.0 % to 5.0 %.
Ultimate tensile strength ($\sigma_u$): 4.5 to 6.0 MPa.
Average crack width ($w_m$): $50\text{--}70\ \mu\text{m}$ regardless of applied tensile strain.
Durability & Self-Healing Metrics:
Water permeability remains at $10^{-11}\text{ m/s}$ even when strained up to 3.0 %.
100 % resonant frequency and stiffness recovery after wet-dry self-healing cycles.
Life-Cycle Sustainability: 40 % lower life-cycle cost and 50 % lower carbon footprint over a 60-year bridge service life.

Linked Atlas nodes

02_concepts/history_of_ecc.md
02_concepts/strain_hardening_criteria.md
04_material_systems/pva_ecc.md
05_experiments/direct_tensile_test.md
02_concepts/life_cycle_analysis.md
04_material_systems/link_slab.md
04_material_systems/seismic_elements.md

Relationship to Victor Li book

Maps directly across all major chapters of Victor Li (2019) Engineered Cementitious Composites (ECC): Bendable Concrete for Sustainable and Resilient Infrastructure.
Serves as the concise, authoritative executive summary of Victor Li's multi-decade research portfolio, capturing both scientific foundations and practical civil engineering impact.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`02_concepts/history_of_ecc.md`	ECC achieves 2–5 % tensile ductility with self-controlled crack widths $< 100\ \mu\text{m}$ using $\le 2.0\text{ vol. \%}$ fibers	Comprehensive micromechanical synthesis and material database across global field projects	Section 2 & 3, Fig. 1-4	verified_from_pdf
`04_material_systems/link_slab.md`	ECC jointless bridge link slabs eliminate expansion joint maintenance and reduce life-cycle carbon by ~50 %	Real-world monitoring of Mihara Bridge and Grove Street Bridge deployments	Section 4, Fig. 5-8, Table 1	verified_from_pdf

Verification status

PDF preserved: yes (li-2016-bendable-concrete.pdf)
Text extracted: yes (full_text/li-2016-bendable-concrete_full_text.md)
Metadata verified: yes (Innovation in Construction, Special Issue, pp. 10–17, 2016)
Claim-evidence matrix ready: yes

Cautions

ECC requires rigorous mixing sequence and rheology control to ensure uniform 3D fiber dispersion and avoid fiber clumping.
Direct tensile dogbone testing requires careful boundary alignment to avoid eccentric bending stresses.