Wang et al. (2019) — Mechanical properties of high ductile magnesium...

Citation

Yichao Wang, Linzhuo Wei, Jiangtao Yu, Kequan Yu (2019). Mechanical properties of high ductile magnesium oxychloride cement-based composites after water soaking. Cement and Concrete Composites, Vol. 97, pp. 248-258.

DOI: 10.1016/j.cemconcomp.2018.12.028
Atlas layer: extension
Related Victor Li book chapter: Chapter 4: Non-Portland Cement ECC; Chapter 7: Durability
Source PDF: wang-2019-mechanical-properties-of-high-ductile.pdf
Extracted text: atlas/full_text/wang-2019-mechanical-properties-of-high-ductile_full_text.md
Source note: atlas/source_notes/wang-2019-mechanical-properties-of-high-ductile_source_note.md

Why this paper matters

Applies micromechanical ECC design to alternative non-Portland air-hardening magnesium oxychloride cement (MOC), overcoming its inherent brittleness and severe water-sensitivity by incorporating 2.0 vol% PE fibers and 20–60% fly ash to achieve tensile ductility of 5.23% to 8.32% and compressive strength retention of 83–93% after 28-day water soaking.

Main contribution

Developed MOC-ECC achieving direct tensile strain capacities of 5.23% to 8.32% and tensile strength up to 6.41 MPa.
Raised the 28-day water soaking compressive strength retention coefficient from 0.40–0.45 (conventional MOC) to 0.83–0.93.
Maintained tight crack widths ($<120\ \mu\text{m}$) and 39–71 microcracks before and after continuous water immersion.

Evidence summary

Tensile properties:
FM20: Air $\sigma_{tu} = 5.84\text{ MPa}$, $\varepsilon_{tu} = 5.23\%$; Water $\sigma_{tu} = 6.41\text{ MPa}$, $\varepsilon_{tu} = 5.80\%$
FM40: Air $\sigma_{tu} = 5.16\text{ MPa}$, $\varepsilon_{tu} = 6.06\%$; Water $\sigma_{tu} = 4.72\text{ MPa}$, $\varepsilon_{tu} = 8.32\%$ ($N_c = 71$, $w_c = 93.5\ \mu\text{m}$) (Table 6, page 251).
Water retention: Compressive strength retention after 28d water soaking was 0.85 (FM20), 0.83 (FM40), and 0.93 (FM60) (Fig. 9, page 254).
Microstructure: Fly ash suppresses phase 5 dissolution and refines matrix porosity (XRD/SEM).

Linked Atlas nodes

04_material_systems/green_ecc.md
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
`04_material_systems/green_ecc.md`	MOC-ECC with 2.0 vol% PE fibers and fly ash delivers direct tensile strain capacity up to 8.32% and tensile strength over 6.4 MPa.	Measured tensile strain capacities ranged from 5.23% to 8.32% in air-cured and water-soaked specimens.	Pages 248, 251, Section 3.2, Table 6	verified_from_pdf
`02_concepts/durability.md`	Fly ash and PE fiber bridging elevate the compressive strength retention coefficient of MOC composites after 28 days of water soaking to 0.83–0.93.	Compressive strength retention was 83% to 93%, significantly outperforming standard MOC (40–45%).	Page 254, Section 3.4, Fig. 9	verified_from_pdf

Verification status

PDF preserved: yes (wang-2019-mechanical-properties-of-high-ductile.pdf)
Text extracted: yes (atlas/full_text/wang-2019-mechanical-properties-of-high-ductile_full_text.md)
DOI verified: yes (10.1016/j.cemconcomp.2018.12.028)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

MOC cannot be used with steel rebar due to free chloride ions promoting severe corrosion; intended for plain or non-ferrous applications.