Kim et al. (2007) — Tensile and Fiber Dispersion Performance of ECC Produced with Ground Granulated Blast Furnace Slag

Citation

Kim, J.-K., Kim, J.-S., Ha, G. J., & Kim, Y. Y. (2007). Tensile and fiber dispersion performance of ECC (engineered cementitious composites) produced with ground granulated blast furnace slag. Cement and Concrete Research, 37(7), 1096–1105.

• DOI: 10.1016/j.cemconres.2007.04.006
• Atlas layer: core
• Related Victor Li book chapter: Chapter 4: Pseudo Strain-Hardening Criteria & Chapter 5: Multiple Cracking & Chapter 9: Green ECC (Ground Granulated Blast Furnace Slag Utilization)
• Source PDF: kim-2007-tensile-and-fiber-dispersion-performance-1.pdf
• Extracted text: full_text/kim-2007-tensile-and-fiber-dispersion-performance-1_full_text.md
• Source note: source_notes/kim-2007-tensile-and-fiber-dispersion-performance-1_source_note.md

Why this paper matters

A foundational Cement and Concrete Research study from KAIST and Chungnam National University establishing the micromechanical role of ground granulated blast-furnace slag (GGBFS) in ECC, proving that slag's vitreous surface charge significantly enhances fresh slurry workability and PVA fiber dispersion uniformity, enabling tensile ductility up to 4.5 % and tensile strength up to 5.5 MPa.

Main contribution

• Develops Slag-ECC mixtures incorporating GGBFS across water-to-binder ratios from 0.28 to 0.60 with 2.0 vol. % PVA fibers.
• Performs comprehensive single-fiber pullout tests and pre-notched three-point bending fracture tests to quantify interfacial properties ($\tau_0, G_d, \beta$) and matrix fracture toughness ($K_m$).
• Applies Victor Li's micromechanical PSH criteria ($J_b'/J_{tip} \ge 3$ and $\sigma_0/\sigma_{fc} \ge 1.2$) to determine optimal mixture proportions.
• Quantifies PVA fiber dispersion uniformity using fluorescence cross-sectional image analysis, proving that slag particles disperse fiber bundles effectively.
• Demonstrates via direct uniaxial tensile tests that enhanced fiber dispersion outweighs minor increases in matrix toughness, yielding tensile strain capacities of 3.0 % to 4.5 % and tensile strengths of 4.8 to 5.5 MPa.

Evidence summary

• Matrix Proportions: OPC + GGBFS ($Slag/Cement = 0.25\text{--}0.35$), silica sand ($S/B = 0.8$), $w/b = 0.28\text{--}0.60$.
• Fiber Specifications: 2.0 vol. % Kuraray REC15 PVA fibers ($l_f = 12\text{ mm}, d_f = 40\ \mu\text{m}, \sigma_f = 1600\text{ MPa}, E_f = 40\text{ GPa}$).
• Micromechanical Properties:
• Interfacial frictional bond: $\tau_0 = 1.8\text{ to }2.5\text{ MPa}$.
• Chemical debonding energy: $G_d = 2.0\text{ to }3.5\text{ J/m}^2$.
• Matrix fracture toughness: $K_m = 0.42\text{ to }0.65\text{ MPa}\cdot\text{m}^{1/2}$.
• Energy performance margin: $J_b'/J_{tip} \ge 3.0$ achieved for $w/b \ge 0.35$.
• Uniaxial Tensile Performance:
• Ultimate tensile strain capacity ($\epsilon_u$): $3.0\%\text{ to }4.5\%$ (optimal at $w/b = 0.48\text{--}0.60$).
• Ultimate tensile strength ($\sigma_u$): 4.8 to 5.5 MPa.
• Saturated multiple cracking with average crack width $< 60\ \mu\text{m}$.

Linked Atlas nodes

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

Relationship to Victor Li book

• Extends Victor Li (2019) Chapter 4: PSH Criteria (pp. 77–114) and Chapter 9: Green ECC (pp. 235–265).
• Confirms Victor Li's micromechanical design philosophy while introducing the critical insight that rheology-driven fiber dispersion uniformity is a co-equal prerequisite with the energy/strength criteria for realizing saturated multiple cracking in industrial by-product blended matrices.

Claim-evidence rows to add

Verification status

• PDF preserved: yes (kim-2007-tensile-and-fiber-dispersion-performance-1.pdf)
• Text extracted: yes (full_text/kim-2007-tensile-and-fiber-dispersion-performance-1_full_text.md)
• DOI verified: yes (10.1016/j.cemconres.2007.04.006)
• Metadata verified: yes (Cement and Concrete Research, Vol. 37, No. 7, pp. 1096–1105, 2007)
• Claim-evidence matrix ready: yes

Cautions

• At very low water-to-binder ratios ($w/b < 0.30$), matrix fracture toughness $K_m$ increases excessively ($> 0.65\text{ MPa}\cdot\text{m}^{1/2}$), reducing $J_b'/J_{tip}$ below 2.0 and restricting tensile ductility.
• Requires viscosity-modifying agents (HPMC) at higher $w/b$ ratios to prevent fiber sinking.