Alemu et al. (2023) — Modified Permeability Test on Self-Healing ECC with SHA and SAP
Citation
Abel Shiferaw Alemu, Jeong-Il Choi, Huy Hoàng Nguyễn, Seongcheol Choi, Jung-Il Suh, Bang Yeon Lee, Hyeong-Ki Kim (2023). On crack healing in fiber-reinforced cementitious composites incorporating mineral-based healing agent and superabsorbent polymer: Evaluation using modified permeability test method. Cement and Concrete Composites, 141, 105111.
- DOI:
10.1016/j.cemconcomp.2023.105111 - Atlas layer: extension
- Related Victor Li book chapter: Chapter 8: Self-Healing and Durability (Section 8.2 & 8.3)
- Source PDF:
primary_data/alemu-2023-on-crack-healing-in-fiber-reinforced.pdfIJP07423E_On crack healing_CCC.pdf` - Extracted text:
secondary_data/full_texts/alemu-2023-on-crack-healing-in-fiber-reinforced_full_text.mdsecondary_data/full_texts/IJP07423E_On crack healing_CCC_full_text.md` - Source note:
secondary_data/source_notes/alemu-2023-on-crack-healing-in-fiber-reinforced_source_note.mdsecondary_data/source_notes/IJP07423E_On crack healing_CCC_source_note.md`
Why this paper matters
Develops a modified active strain-controlled constant-head permeability testing apparatus for fiber-reinforced ECCs (1.25 vol. % PE/PVA hybrid, 50 % slag cement). Proves that fiber bridging is the primary mechanism enabling 90 % water permeability reduction even for large cracks up to 0.80 mm (at 3 % strain), while 0.5 % superabsorbent polymer (SAP) accelerates rapid early sealing (healed fraction 0.95–1.0 within 24 h) and mineral healing agents (SHA) enhance unloaded stiffness/resonant frequency recovery.
Main contribution
- Active Strain-Controlled Permeability Apparatus: Established a standardized constant-head (0.5 m) water permeability setup using embedded conduits and adjustable truss jigs for multi-cracked ECC under controlled residual strain (0.3 % to 3.0 %).
- Fiber Bridging Water-Tightness Retention: Demonstrated that fiber bridging maintains a healed fraction of 0.90 even at 2.0–3.0 % strain with crack widths of 0.58–0.80 mm, far exceeding plain mortar limits ($<0.1$ healing).
- Differentiated Healing Mechanisms (SAP vs SHA): Proved 0.5 wt. % SAP hydrogel delivers rapid early crack blockage (healed fraction 0.95–1.0) while preserving 65.8 MPa compressive strength, whereas mineral SHA (OPC/CSA/anhydrite) excels in unloaded stiffness and resonant frequency recovery.
Evidence summary
- Mechanical Properties:
R1-F1.25(Control): $f_c = 45.0\text{ MPa}$, $\sigma_{tu} = 7.3\text{ MPa}$, $\epsilon_u = 6.20\text{ \%}$ (Table 3, Page 8).R2-F1.25: $f_c = 82.7\text{ MPa}$, $\sigma_{tu} = 8.5\text{ MPa}$, $\epsilon_u = 6.54\text{ \%}$.SAP0.5-F1.25: $f_c = 65.8\text{ MPa}$, $\sigma_{tu} = 7.3\text{ MPa}$, $\epsilon_u = 6.53\text{ \%}$.SHA15-F1.25: $f_c = 52.5\text{ MPa}$, $\sigma_{tu} = 6.2\text{ MPa}$, $\epsilon_u = 4.95\text{ \%}$.- Permeability Reduction & Healed Fraction:
- 0.3 % & 1.0 % strain: Watertight (healed fraction = 1.0) in 6–12 h ($MCW = 0.05\text{--}0.18\text{ mm}$) (Fig. 10, Page 8).
- 2.0 % & 3.0 % strain: Healed fraction reached 0.90 in 24–48 h ($MCW = 0.58\text{--}0.80\text{ mm}$).
- Fiber Reduction (0.5 % PE): Initial flow increased by 8–30x; 28d healed fraction dropped by 64–84 % (Figs. 12–15 & 26, Pages 9–13).
- Plain Mortar (F0): Single 1.42 mm crack at 2 % strain had zero healing ($<0.1$).
- SAP vs SHA Performance:
SAP0.5: Healed fraction 0.95–1.0; swollen hydrogel physically sealed crack openings (Figs. 22–23, Page 12).SHA15: Highest resonant frequency (RF) and stiffness recovery under unrestrained conditions (Figs. 20–21, Page 11).
Linked Atlas nodes
04_material_systems/self_healing_ecc.md02_concepts/permeability.md04_material_systems/green_ecc.md05_experiments/crack_width_distribution.md
Relationship to Victor Li book
- Primary book anchor remains Victor Li (2019), Engineered Cementitious Composites (ECC).
- Directly extends Chapter 8 (Self-Healing and Durability, Section 8.2 & 8.3) by establishing a standardized active strain-controlled permeability testing methodology for multi-cracked composites, discovering that fiber bridging continues to deliver a 90 % healed fraction even when crack widths exceed the traditional 0.15 mm threshold (up to 0.80 mm at 3 % strain), while 0.5 % SAP hydrogel addition enables rapid 24 h watertightness.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
02_concepts/permeability.md |
Fiber bridging enables multi-cracked ECC to achieve 90 % water permeability reduction even at 2–3 % strain with crack widths up to 0.80 mm | Permeability measurements verified 0.90 healed fraction at 2–3 % strain | Page 105111:7 & 13 / Section 3.1 & Conclusions | Fig. 10 & Fig. 27 |
04_material_systems/self_healing_ecc.md |
Fiber content governs permeability reduction: reducing PE fibers from 1.25 % to 0.5 % drops 28-day healed fraction by 64–84 % | Permeability comparisons showed 8–30x higher initial flow and 64–84 % lower healing in F0.5 | Page 105111:7 & 10 / Section 3.2 | Figs. 12–15 & Fig. 26 |
04_material_systems/self_healing_ecc.md |
Adding 0.5 % SAP achieves rapid crack sealing (healed fraction 0.95–1.0) within 24 h while preserving 65.8 MPa compressive strength | Water discharge tests confirmed 0.95 healed fraction at 28 days with $f_c = 65.8\text{ MPa}$ | Page 105111:8, 11, 14 / Section 3.4 & Table 3 | Table 3 / Figs. 22, 28 |
Verification status
- PDF preserved: yes (in
primary_data/IJP07423E_On crack healing_CCC.pdf) - Text extracted: yes (PyMuPDF, 18 pages)
- DOI verified: yes (
10.1016/j.cemconcomp.2023.105111) - Page/figure/table verified: yes (all checked in PDF text)
- Claim-evidence matrix ready: yes
Cautions
- SHA increases matrix stiffness, which can slightly increase crack width under restrained tension (lowering water-flow healed fraction to 0.77).
- SAP content $>0.5\text{ \%}$ causes compressive strength degradation.