Extreme-Ductility ECC Research Lineage

Purpose

This lineage map collects ECC/SHCC/HPFRCC studies that increase tensile ductility, achieve high-strength/high-ductility combinations, or create ultra-ductile ECC variants. The map is an extension-layer genealogy built on the Victor Li 2019 book anchor.

Book-anchor position

Victor Li 2019 book establishes the design logic:

fiber + matrix + interface + flaw distribution
  -> strain-hardening criteria
  -> multiple microcracking
  -> controlled crack width
  -> high tensile ductility

The extreme-ductility lineage asks how researchers pushed that base mechanism further.

Initial mechanism genealogy

Li & Leung 1992
  -> steady-state / multiple cracking theory

Lin & Li 1997; Redon 2001; Li et al. 2002
  -> interface and slip-hardening control
  -> PVA-ECC high ductility

Wang & Li 2004; Li & Wang 2006; Lu et al. 2018
  -> flaw distribution / artificial flaw / cracking-strength control
  -> saturated cracking robustness

Li & Li 2012; Zhou et al. 2012; Tosun-Felekoglu et al. 2014
  -> processing, rheology, fiber dispersion, fiber orientation
  -> robust tensile ductility and reduced scatter

Ranade et al. 2013 and later papers
  -> high-strength + high-ductility concrete / ECC extension

Post-2019 latest studies
  -> ultra-ductile, hybrid, low-carbon, high-strength/high-ductility, and data-driven ductility optimization

Classification axes

Axis	Question
Ductility level	What tensile strain capacity is reported, and under what direct-tension protocol?
Strength level	Is high compressive or tensile strength also achieved?
Crack control	Are crack width and spacing controlled?
Mechanism	Interface / flaw / fiber / dispersion / matrix / hybrid route?
Robustness	Is performance reproducible across specimens and batches?
Sustainability	Does ductility improvement increase or reduce embodied carbon?
Application	Is the material used for repair, impact/blast, seismic, overlays, or smart functions?

Next work

Acquire Priority A PDFs from 03_papers/extreme_ductility_extension_paper_request_list.md.
Create paper cards and extension claim-evidence rows.
Add graph edges from papers to extreme_ductility_ecc, strain_hardening_criteria, fiber_bridging_law, flaw_design, fiber_dispersion, and direct_tensile_test.
Build a timeline CSV once at least 10 extension papers are ingested.