Zhou et al. (2018) — Mechanical Properties of Hybrid Ultra-High Performance...

Citation

Yingwu Zhou, Bin Xi, Kequan Yu, Lili Sui, Feng Xing (2018). Mechanical Properties of Hybrid Ultra-High Performance Engineered Cementitous Composites Incorporating Steel and Polyethylene Fibers. Materials, Vol. 11, Issue 8, Article 1448.

DOI: 10.3390/ma11081448
Atlas layer: extension
Related Victor Li book chapter: Chapter 3: Hybrid Fiber Systems; Chapter 5: Ultra-High Performance ECC
Source PDF: zhou-2018-mechanical-properties-of-hybrid-ultra-high.pdf
Extracted text: atlas/full_text/zhou-2018-mechanical-properties-of-hybrid-ultra-high_full_text.md
Source note: atlas/source_notes/zhou-2018-mechanical-properties-of-hybrid-ultra-high_source_note.md

Why this paper matters

Systematically investigates the hybridization of steel (ST) and polyethylene (PE) fibers in ultra-high performance cementitious matrices ($V_{f,total} = 2.0\%$), finding that the 1.5% PE + 0.5% ST blend achieves an optimal synergy of 110.6 MPa compressive strength, 12.4 MPa tensile strength, 8.1% tensile strain capacity, and improved fresh fluidity (170 mm).

Main contribution

Overcame the workability penalty of high-aspect-ratio PE fibers ($L_f/d_f = 750$) by hybridizing with straight steel fibers ($L_f/d_f = 65$).
Proved that steel fibers enhance compressive strength (99.5 to 150.5 MPa) and crack width restraint (80 $\mu\text{m}$), while PE fibers ensure pseudo strain-hardening ductility (scaling up to 9.1%).
Mapped the micromechanical $J_b'/J_{tip}$ PSH index across 5 fiber hybrid ratios.

Evidence summary

Tensile properties across mixes:
2.0% PE: $\sigma_{tu} = 15.5\text{ MPa}$, $\varepsilon_{tu} = 9.1\%$, $g_{se} = 1094.2\text{ kJ/m}^3$
1.5% PE + 0.5% ST: $\sigma_{tu} = 12.4\text{ MPa}$, $\varepsilon_{tu} = 8.1\%$, $g_{se} = 700.4\text{ kJ/m}^3$
1.0% PE + 1.0% ST: $\sigma_{tu} = 9.9\text{ MPa}$, $\varepsilon_{tu} = 2.2\%$, $g_{se} = 138.4\text{ kJ/m}^3$
0.5% PE + 1.5% ST: $\sigma_{tu} = 11.3\text{ MPa}$, $\varepsilon_{tu} = 1.6\%$, $g_{se} = 93.6\text{ kJ/m}^3$
2.0% ST: $\sigma_{tu} = 8.5\text{ MPa}$, $\varepsilon_{tu} = 0.41\%$ (strain-softening).
Compressive properties: Compressive strength scales linearly with steel fiber volume from 99.5 MPa (2% PE) to 150.5 MPa (2% ST).
Flexural MOR: 4-point bending strength reaches 30.3 MPa in 2.0% PE and 26.5 MPa in 1.5% PE + 0.5% ST.

Linked Atlas nodes

02_concepts/extreme_ductility_ecc.md
02_concepts/interface_properties.md
02_concepts/strain_hardening_criteria.md
05_experiments/direct_tensile_test.md

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`02_concepts/extreme_ductility_ecc.md`	Hybrid UHP-ECC combining 1.5% PE and 0.5% steel fibers achieves 110.6 MPa compressive strength, 12.4 MPa tensile strength, and 8.1% tensile ductility with 170 mm slump spread.	Experimental testing confirmed 1.5% PE + 0.5% ST blend maintained 8.1% ductility and 12.4 MPa tensile strength at $f_c = 110.6\text{ MPa}$.	Pages 1450-1456, Section 3.2 & 3.4, Figs. 6, 7, 14	verified_from_pdf
`02_concepts/interface_properties.md`	Increasing steel fiber ratio enhances compressive strength (99.5 to 150.5 MPa) and fluidity (140 to 330 mm) but lowers tensile strain capacity below 1.5% PE.	Compressive strength and slump flow increased with ST content, while strain capacity experienced a sharp drop below 1.5% PE.	Pages 1450, 1456, Section 3.1 & 3.4, Figs. 6, 14	verified_from_pdf

Verification status

PDF preserved: yes (zhou-2018-mechanical-properties-of-hybrid-ultra-high.pdf)
Text extracted: yes (atlas/full_text/zhou-2018-mechanical-properties-of-hybrid-ultra-high_full_text.md)
DOI verified: yes (10.3390/ma11081448)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

Straight smooth steel fibers were used; hooked or twisted steel fibers would provide higher mechanical interlock but may lower workability.