Zhu et al. (2019) — Development of 3D printable engineered cementitious...

Citation

Binrong Zhu, Jinlong Pan, Behzad Nematollahi, Zhenxin Zhou, Yang Zhang, Jay Sanjayan (2019). Development of 3D printable engineered cementitious composites with ultra-high tensile ductility for digital construction. Materials & Design, Vol. 181, Article 108088.

DOI: 10.1016/j.matdes.2019.108088
Atlas layer: extension
Related Victor Li book chapter: Chapter 5: Advanced ECC; Chapter 6: Structural Applications
Source PDF: zhu-2019-development-of-3d-printable-engineered.pdf
Extracted text: atlas/full_text/zhu-2019-development-of-3d-printable-engineered_full_text.md
Source note: atlas/source_notes/zhu-2019-development-of-3d-printable-engineered_source_note.md

Why this paper matters

Landmark breakthrough in digital construction, achieving a world-record 3D-printed direct tensile strain capacity of 11.43% (tensile strength 5.35 MPa, compressive strength 54–56 MPa, 132 microcracks with average width 69.3 μm) by leveraging extrusion shear-induced PE fiber alignment.

Main contribution

Developed 3D-printable PE-ECC integrating high buildability (17-layer shape retention) with extreme tensile ductility ($\varepsilon_{tu} > 8\text{--}11\%$).
Proved that 3D-printed ECC outperforms conventionally cast counterparts in ductility (11.43% vs 10.03%) and crack width control ($69.3\ \mu\text{m}\text{ vs }75.7\ \mu\text{m}$) due to nozzle extrusion fiber alignment.
Formulated an early-strength, green thixotropic matrix using OPC + Sulfoaluminate cement + Fly ash + Attapulgite nano-clay + HPMC.

Evidence summary

Tensile properties comparison (M2, 2.0% PE):
3D-Printed: $\sigma_{tu} = 5.35 \pm 0.5\text{ MPa}$, $\varepsilon_{tu} = 11.43 \pm 0.73\%$, $g_{se} = 477.07\text{ kJ/m}^3$, $N_c = 132$, $w_c = 69.3\ \mu\text{m}$
Mold-Cast: $\sigma_{tu} = 5.03 \pm 0.7\text{ MPa}$, $\varepsilon_{tu} = 10.03 \pm 0.85\%$, $g_{se} = 407.61\text{ kJ/m}^3$, $N_c = 106$, $w_c = 75.7\ \mu\text{m}$ (Table 5, page 8).
Compressive and flexural strength: 28d compressive strength = 54–56 MPa, flexural strength = 16–18 MPa (Fig. 11, page 9).
Buildability: 17-layer printed cylinder achieved height deviation $H = 0.8\%$ and width deviation $W = 5.5\%$ (Table 4, page 7).

Linked Atlas nodes

02_concepts/extreme_ductility_ecc.md
02_concepts/interface_properties.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`	3D-printed PE-ECC achieves tensile strain capacity of 11.43% with 132 microcracks (average width 69.3 μm), surpassing mold-cast equivalents.	Measured uniaxial tensile strain capacity of 3D-printed M2 was $11.43 \pm 0.73\%$, exceeding the $10.03 \pm 0.85\%$ of mold-cast specimens.	Pages 1, 8, Section 3.2, Table 5	verified_from_pdf
`02_concepts/interface_properties.md`	Extrusion shear during 3D printing aligns PE fibers along the deposition vector, enhancing crack bridging efficiency.	Microstructural SEM and pore analysis confirmed preferential longitudinal fiber orientation and pore refinement in printed specimens.	Pages 10-12, Section 3.3, Figs. 12-14	verified_from_pdf

Verification status

PDF preserved: yes (zhu-2019-development-of-3d-printable-engineered.pdf)
Text extracted: yes (atlas/full_text/zhu-2019-development-of-3d-printable-engineered_full_text.md)
DOI verified: yes (10.1016/j.matdes.2019.108088)
Page/figure/table verified: yes
Claim-evidence matrix ready: yes

Cautions

Tensile testing was along the printing direction; perpendicular (cross-layer) tensile properties will exhibit anisotropic behavior.