Lin et al. (2022) — Effects of sodium aluminate on the performance of seawater...

Citation

Chenlong Lin, Siyu Wang, Wentao Ma, Yuhong Yan, Yiyan Lu (2022). Effects of sodium aluminate on the performance of seawater sea-sand engineered cementitious composites. Construction and Building Materials, Vol. 345, Article 128422.

DOI: 10.1016/j.conbuildmat.2022.128422
Atlas layer: extension
Related Victor Li book chapter: Chapter 4: Sustainable/Marine ECC; Chapter 8: Constitutive Modeling
Source PDF: lin-2022-effects-of-sodium-aluminate-on.pdf
Extracted text: atlas/full_text/lin-2022-effects-of-sodium-aluminate-on_full_text.md
Source note: atlas/source_notes/lin-2022-effects-of-sodium-aluminate-on_source_note.md

Why this paper matters

Develops rapid-setting seawater sea-sand ECC (SS-ECC) reinforced with low-cost PVA fibers by incorporating sodium aluminate ($NaAlO_2$, up to 4%), which drastically cuts setting time by 97.4%, enhances early strength, doubles tensile strain capacity from 2.17% to 4.18% (peaking at 4.61%), and formulates a calibrated bilinear constitutive model.

Main contribution

Demonstrated that 4% $NaAlO_2$ in seawater reduces setting time by 97.4% (initial set in 11 min) for rapid emergency marine construction.
Enhanced tensile ductility from 2.17% (control) to 4.18% (4% NA, max 4.61%) with 3.75 MPa tensile strength and 50–70 μm crack widths.
Established a simplified bilinear tensile constitutive relationship ($E_1 = 7.13\text{--}13.64\text{ GPa}$, $E_2 = 0.045\text{--}0.069\text{ GPa}$) for engineering structural simulations.

Evidence summary

Setting time: 4% NA in seawater reduced initial set from 420 min to 11 min and final set from 580 min to 31 min (Fig. 5, page 5).
Compressive strength: 1d strength rose +73% to $3.97\text{ MPa}$; 28d strength was $30.05\text{--}32.20\text{ MPa}$ in seawater mixes (Table 4, page 5).
Direct tensile properties:
S4 (4% NA, seawater): $\sigma_{tc} = 1.86\text{ MPa}$, $\sigma_{tu} = 3.75 \pm 0.24\text{ MPa}$, $\varepsilon_{tu} = 4.18 \pm 0.31\%$ (max 4.61%), toughness $0.130\text{ MPa}\cdot\text{mm/mm}$.
S0 (0% NA, seawater): $\sigma_{tc} = 2.16\text{ MPa}$, $\sigma_{tu} = 3.26 \pm 0.24\text{ MPa}$, $\varepsilon_{tu} = 2.17 \pm 0.12\%$ (Table 5, page 9, Fig. 8).
Hydration mechanism: XRD and TGA proved accelerated clinker hydration, AFt-to-AFm transformation, and Friedel's salt formation.

Linked Atlas nodes

04_material_systems/green_ecc.md
02_concepts/extreme_ductility_ecc.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
`04_material_systems/green_ecc.md`	Adding 4% sodium aluminate to PVA-reinforced seawater sea-sand ECC cuts setting time by 97% and doubles tensile strain capacity to 4.18% (max 4.61%).	Vicat setting and JSCE tensile testing verified setting reduction to 11 min and ultimate strain increase to 4.18%.	Pages 1, 5, 9, Section 3.1 & 3.3, Table 5, Fig. 5	verified_from_pdf
`02_concepts/strain_hardening_criteria.md`	Sodium aluminate promotes C-S-H, AFm, and N-A-S-H polycondensation, maintaining crack widths of 50–70 μm and meeting elastoplastic criteria.	Optical crack measurement and XRD/TGA confirmed tight crack widths and ideal elastoplastic toughness indexes (R > 100).	Pages 1, 6, 8, Section 3.3, Tables 5, 7, 8	verified_from_pdf

Verification status

PDF preserved: yes (lin-2022-effects-of-sodium-aluminate-on.pdf)
Text extracted: yes (atlas/full_text/lin-2022-effects-of-sodium-aluminate-on_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2022.128422)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

Late-age strength (60d) shows a slight plateau due to dense early hydration shell formation.