Nguyễn et al. (2023) — High-Strength Ultra-Ductile Geopolymer Composite with C-(N)-A-S-H Healing

Citation

Huy Hoàng Nguyễn, Phương Hoàng Nguyễn, Quang-Hiếu Lương, Weina Meng, Bang Yeon Lee (2023). Mechanical and autogenous healing properties of high-strength and ultra-ductility engineered geopolymer composites reinforced by PE-PVA hybrid fibers. Cement and Concrete Composites, 142, 105155.

• DOI: 10.1016/j.cemconcomp.2023.105155
• Atlas layer: extension
• Related Victor Li book chapter: Chapter 9: Green ECC & Chapter 8: Self-Healing and Durability
• Source PDF: primary_data/nguyen-2023-mechanical-and-autogenous-healing-properties.pdfIJP07523E_Mechanical and authgenous healing_PEPVA EGC_CCC.pdf`
• Extracted text: secondary_data/full_texts/nguyen-2023-mechanical-and-autogenous-healing-properties_full_text.mdsecondary_data/full_texts/IJP07523E_Mechanical and authgenous healing_PEPVA EGC_CCC_full_text.md`
• Source note: secondary_data/source_notes/nguyen-2023-mechanical-and-autogenous-healing-properties_source_note.mdsecondary_data/source_notes/IJP07523E_Mechanical and authgenous healing_PEPVA EGC_CCC_source_note.md`

Why this paper matters

Breaks the historical tradeoff between compressive strength and tensile ductility in cementless geopolymers (HSUD-EGC), achieving a compressive strength of 87.0 MPa with 10.51 % tensile strain capacity in slag-rich S-PE ($p_{index} = 914\text{ MPa}\cdot\text{\%}$) and 50.0 MPa with 11.99 % ductility in fly ash-rich F-PE (1.5 vol. % PE-PVA hybrid). Identifies C-(N)-A-S-H gel as the governing autogenous healing product, which increases post-healing reloading tensile strength to 7.53 MPa (+13.4 % over virgin strength).

Main contribution

• 87 MPa High-Strength & 10.5 % Ultra-Ductility: Slag-rich composite (S-PE, GGBS:FA = 5.5:4.0, 1.0 % PE + 0.5 % PVA) achieved $87.0\text{ MPa}$ compressive strength and $10.51 \pm 0.34\text{ \%}$ direct tensile strain capacity ($\sigma_{tu} = 6.64\text{ MPa}$); fly ash-rich F-PE reached $50.0\text{ MPa}$ and $11.99 \pm 0.31\text{ \%}$ ductility ($\sigma_{tu} = 5.18\text{ MPa}$).
• Record Performance Index & Cost Optimization: Delivered a structural performance index ($f_c \times \epsilon_u$) of $914\text{ MPa}\cdot\text{\%}$ in S-PE while substantially lowering material cost by substituting expensive PE fibers with lower-cost PVA fibers (1:2 ratio).
• C-(N)-A-S-H Gel Healing & Reloading Surge: After 3.0 % pre-strain and 28-day water curing, SEM/EDS confirmed C-(N)-A-S-H gel precipitation within cracks, elevating reloading tensile strength to $7.53 \pm 0.30\text{ MPa}$ (+13.4 %) with $9.45\text{ \%}$ residual strain capacity.

Evidence summary

• 28-Day Compressive Strength: S-PE = $87.0\text{ MPa}$, S-PVA = $86.5\text{ MPa}$, F-PE = $52.0\text{ MPa}$ (50.0 MPa in abstract), F-PVA = $51.9\text{ MPa}$ (Table 4 & Fig. 3, Pages 2 & 5).
• Direct Tensile Performance (28d):
• S-PE (Slag-rich, 1.0 % PE + 0.5 % PVA): $\epsilon_{sc} = \mathbf{10.51 \pm 0.34\text{ \%}}$, $\sigma_{tu} = 6.64 \pm 0.23\text{ MPa}$, $\sigma_{fc} = 3.70\text{ MPa}$, 84.3 cracks ($w_c = 100.3\ \mu\text{m}$, $l_c = 0.96\text{ mm}$) (Table 5 & Figs. 4–5, Pages 3–4).
• F-PE (Fly ash-rich, 1.0 % PE + 0.5 % PVA): $\epsilon_{sc} = \mathbf{11.99 \pm 0.31\text{ \%}}$ (12.0 %), $\sigma_{tu} = 5.18 \pm 0.08\text{ MPa}$, $\sigma_{fc} = 2.70\text{ MPa}$, 74.7 cracks ($w_c = 128.4\ \mu\text{m}$).
• S-PVA: $\epsilon_{sc} = 6.79\text{ \%}$, $\sigma_{tu} = 6.04\text{ MPa}$; F-PVA: $\epsilon_{sc} = 10.35\text{ \%}$, $\sigma_{tu} = 4.60\text{ MPa}$.
• Performance Index: $p_{index} = f_c \times \epsilon_{sc} = \mathbf{914\text{ MPa}\cdot\text{\%}}$ in S-PE (Fig. 6, Page 4).
• Autogenous Healing & Post-Healing Reloading (3.0 % pre-strain):
• S-PVA achieved +76.9 % normalized RF recovery ($RFr = 42.3\text{ \%p}$) (Figs. 11–12, Page 8).
• S-PE post-healing reloading tensile strength reached $7.53 \pm 0.30\text{ MPa}$ (+13.4 %) with $9.45\text{ \%}$ residual strain capacity (Table 8 & Fig. 13, Page 9).
• SEM/EDS confirmed healing material is C-(N)-A-S-H gel (Table 9 & Figs. 14–16, Pages 10–11).

Linked Atlas nodes

• 04_material_systems/green_ecc.md
• 04_material_systems/self_healing_ecc.md
• 02_concepts/strain_hardening_criteria.md
• 05_experiments/direct_tensile_test.md

Relationship to Victor Li book

• Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
• Directly extends Chapter 9 (Green ECC) and Chapter 8 (Self-Healing) by demonstrating that slag-fly ash geopolymer matrices reinforced with PE-PVA hybrid fibers achieve 87.0 MPa compressive strength, 10.51 % direct tensile strain capacity ($p_{index} = 914\text{ MPa}\cdot\text{\%}$), and C-(N)-A-S-H gel autogenous healing that increases post-healing tensile strength to 7.53 MPa (+13.4 %).

Claim-evidence rows to add

Verification status

• PDF preserved: yes (in primary_data/IJP07523E_Mechanical and authgenous healing_PEPVA EGC_CCC.pdf)
• Text extracted: yes (PyMuPDF, 13 pages)
• DOI verified: yes (10.1016/j.cemconcomp.2023.105155)
• Page/figure/table verified: yes (all checked in PDF text)
• Claim-evidence matrix ready: yes

Cautions

• Elevated temperature curing ($100\ ^\circ\text{C}$ for 24 h) is necessary for high-strength geopolymerization.
• Fly ash-rich mixtures show low stiffness recovery due to slower ion leaching kinetics compared to slag.