Sui et al. (2018) — Flexural Fatigue Properties of Ultra-High Performance...

Citation

Lili Sui, Qianli Zhong, Kequan Yu, Feng Xing, Pengda Li, Yingwu Zhou (2018). Flexural Fatigue Properties of Ultra-High Performance Engineered Cementitious Composites (UHP-ECC) Reinforced by Polymer Fibers. Polymers, Vol. 10(8), Article 892.

DOI: 10.3390/polym10080892
Atlas layer: extension
Related Victor Li book chapter: Chapter 8: Durability and Fatigue; Chapter 5: High-Strength ECC
Source PDF: sui-2018-flexural-fatigue-properties-of-ultra-high.pdf
Extracted text: atlas/full_text/sui-2018-flexural-fatigue-properties-of-ultra-high_full_text.md
Source note: atlas/source_notes/sui-2018-flexural-fatigue-properties-of-ultra-high_source_note.md

Why this paper matters

Pioneering study evaluating the flexural fatigue endurance limit, crack opening displacement (COD), and interfacial degradation mechanisms of 120 MPa PE-reinforced UHP-ECC under cyclic bending, proving that UHP-ECC achieves an endurance limit >2 million cycles at S = 0.5 with 86% residual flexural strength.

Main contribution

Characterized the flexural fatigue performance of 120 MPa UHP-ECC across stress levels $S = 0.50$ to $0.90$ at 8 Hz.
Proved that UHP-ECC sustains 2,000,000 cycles at $S = 0.5$ without failure, retaining 86% of its static flexural capacity and $>3\%$ ductile deformation capacity.
Demonstrated via ESEM that high cyclic stress degrades interfacial bonding, causing fiber pullout and surface abrasion, while low fatigue stress causes fiber fatigue rupture.

Evidence summary

Static material properties: 90-day compressive strength = $120.7 \pm 0.75\text{ MPa}$ (28d = $102.8\text{ MPa}$); direct tensile strength up to $12\text{ MPa}$; tensile strain capacity $>8\%$; crack width $<160\ \mu\text{m}$.
Static 4-point flexure: Flexural strength $\approx 22\text{ MPa}$, deflection $>10\text{ mm}$ (deflection/span $>1/30$).
Fatigue endurance: Run-out at $S = 0.5$ ($N > 2 \times 10^6$ cycles); initial stiffness = $130.01\text{ kN/mm} \rightarrow 108.12\text{ kN/mm}$ post-fatigue.

Linked Atlas nodes

02_concepts/extreme_ductility_ecc.md
02_concepts/durability.md
05_experiments/direct_tensile_test.md

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`02_concepts/durability.md`	UHP-ECC exhibits a flexural fatigue endurance limit exceeding 2 million cycles at S = 0.5, retaining 86% residual flexural strength.	Specimens survived 2 million cycles at 50% stress level with post-fatigue flexural strength approaching 19 MPa.	Pages 892-898, Section 3.1, Figs. 7, 8	verified_from_pdf
`02_concepts/extreme_ductility_ecc.md`	120 MPa UHP-ECC achieves tensile strength of 12 MPa, direct tensile ductility >8%, and crack widths <160 $\mu\text{m}$.	Direct tension tests confirmed $\varepsilon_{tu} > 8\%$ and crack widths $<160\ \mu\text{m}$ in 120 MPa UHP-ECC.	Page 892, Section 2.2, Figs. 4, 5	verified_from_pdf

Verification status

PDF preserved: yes (sui-2018-flexural-fatigue-properties-of-ultra-high.pdf)
Text extracted: yes (atlas/full_text/sui-2018-flexural-fatigue-properties-of-ultra-high_full_text.md)
DOI verified: yes (10.3390/polym10080892)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

90-day cured specimens were tested to avoid concurrent hydration effects during cycling.
High cyclic stress causes fiber-matrix interface degradation and fiber flattening.