Gao et al. (2025) — Effects of saline contents on tensile behavior and fiber-matrix interaction...

Citation

Xiumei Gao, Weiwen Li, Linyuwen Ke, Peng Wang, Jiaying Wei, Ying Zhong, Haoliang Wu, Yingwu Zhou (2025). Effects of saline contents on tensile behavior and fiber-matrix interaction in seawater sea-sand engineered cementitious composite (SS-ECC). Construction and Building Materials, Vol. 467, Article 140306.

DOI: 10.1016/j.conbuildmat.2025.140306
Atlas layer: extension
Related Victor Li book chapter: Chapter 4: Special ECCs / Marine Infrastructure; Chapter 2: Micromechanics and Materials Design
Source PDF: gao-2025-effects-of-saline-contents-on.pdf
Extracted text: atlas/full_text/gao-2025-effects-of-saline-contents-on_full_text.md
Source note: atlas/source_notes/gao-2025-effects-of-saline-contents-on_source_note.md

Why this paper matters

Elucidates the multiscale effects of seawater and sea-sand on the tensile strain hardening and single-fiber interface in normal-strength (PVA) and high-strength (PE) ECCs, demonstrating that saline hydration acceleration enhances single PE fiber bond strength by 24.9% and chemical debonding energy by 79.4% while preserving robust tensile strain capacity (4.37% in PE-SS-ECC) and tight crack widths (50 µm).

Main contribution

Directly connected macroscopic tensile strain-hardening behaviors with microscopic single-fiber pullout parameters under seawater/sea-sand exposure.
Quantified the increase in PE single-fiber bond strength ($\tau_{max} = 3.59\text{ MPa}$, +24.9%) and frictional bond strength ($\tau_{fb} = 1.84\text{ MPa}$, +18.3%) due to saline hydration acceleration.
Proved that average crack width remains consistently tight at $50\ \mu\text{m}$ across both freshwater and marine mixes.

Evidence summary

Direct tensile properties:
PE-S-28d (High-strength SS-ECC): $\sigma_u = 13.9\text{ MPa}$, $\varepsilon_u = 4.37\%$, crack width $50\ \mu\text{m}$, $N = 21$ cracks.
PE-F-28d (Freshwater PE-ECC): $\sigma_u = 14.1\text{ MPa}$, $\varepsilon_u = 4.87\%$, crack width $50\ \mu\text{m}$, $N = 40$ cracks.
PVA-S-28d (Normal-strength SS-ECC): $\sigma_u = 4.5\text{ MPa}$, $\varepsilon_u = 2.60\%$, crack width $50\ \mu\text{m}$.
PVA-F-28d (Freshwater PVA-ECC): $\sigma_u = 4.5\text{ MPa}$, $\varepsilon_u = 3.30\%$, crack width $50\ \mu\text{m}$ (Section 3.1, Table 3, Figs. 5, 6, 7).
Single fiber pullout: PE-S single fiber peak load reached $P_a = 0.81\text{ N}$ vs PE-F $0.65\text{ N}$; chemical debonding energy $E_d$ increased by 79.4% (Table 4, Figs. 8, 11, 12).
Hydration kinetics: Isothermal calorimetry revealed accelerated C3S/C2S reaction and Friedel's salt formation at $2\theta = 9.05^\circ, 23.06^\circ$ (Section 3.3, Figs. 14, 15).

Linked Atlas nodes

04_material_systems/green_ecc.md
04_material_systems/high_strength_ecc.md
02_concepts/strain_hardening_criteria.md
05_experiments/single_fiber_pullout.md
05_experiments/direct_tensile_test.md

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`05_experiments/single_fiber_pullout.md`	Seawater and sea sand accelerate cement hydration and increase 28-day PE fiber-matrix interfacial bond strength by 24.9% (to 3.59 MPa) and chemical debonding energy by 79.4%.	Single-fiber pullout tests on 28d specimens and isothermal calorimetry verified bond strengthening and hydration acceleration.	Pages 1, 5, 7, 10, Section 3.2.2, 3.2.3 & Abstract, Tables 3, 4, Figs. 11a, 12a	verified_from_pdf
`04_material_systems/high_strength_ecc.md`	High-strength SS-ECC with 2.0 vol% PE fibers achieves 13.9 MPa ultimate tensile strength and 4.37% tensile strain capacity with tightly controlled crack widths averaging 50 µm.	JSCE uniaxial dogbone tensile testing confirmed 13.9 MPa tensile strength and 4.37% strain capacity.	Pages 1, 5, 7, Section 3.1.2, 3.1.3 & Abstract, Table 3, Figs. 5a, 6, 7d	verified_from_pdf

Verification status

PDF preserved: yes (gao-2025-effects-of-saline-contents-on.pdf)
Text extracted: yes (atlas/full_text/gao-2025-effects-of-saline-contents-on_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2025.140306)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

Saline acceleration in PVA-ECC increases matrix stiffness and causes PVA fibers to rupture prematurely, reducing tensile ductility from 3.30% to 2.60%.