Raza et al. (2024) — Material Characterization and Thermal Performance of Polyethylene Fiber-Reinforced Lightweight Engineered Geopolymer Composites Subjected to Sulfate Attacks
Citation
Raza, A., Salmi, A., El Ouni, M. H., Ghazouani, N., Ahmed, B., & Chen, W. (2024). Material characterization and thermal performance of polyethylene fiber-reinforced lightweight engineered geopolymer composites subjected to sulfate attacks. Construction and Building Materials, 455, 139156.
- DOI:
10.1016/j.conbuildmat.2024.139156 - Atlas layer: core
- Related Victor Li book chapter: Chapter 4: Pseudo Strain-Hardening Criteria & Chapter 7: Alternative Reinforcing Fibers (PE Fibers) & Chapter 9: Lightweight Green ECC & Chapter 10: Durability in Aggressive Sulfate Environments (pp. 343–384)
- Source PDF:
raza-2024-material-characterization-and-thermal-performance.pdf - Extracted text:
full_text/raza-2024-material-characterization-and-thermal-performance_full_text.md - Source note:
source_notes/raza-2024-material-characterization-and-thermal-performance_source_note.md
Why this paper matters
A comprehensive international durability study across 6 institutions evaluating lightweight PE-reinforced engineered geopolymer composites (LEGP) made with expanded glass aggregates subjected to a 180-day 5 wt% $\text{Na}_2\text{SO}_4$ sulfate attack, proving that 100 % slag geopolymer matrices outperform lightweight Portland ECC in residual strength, pore refinement (MIP), and high-temperature thermal stability (TGA/DTG).
Main contribution
- Develops sustainable Lightweight Engineered Geopolymer Composites (LEGP) using expanded glass aggregates (EGA) and 2.0 vol. % PE fibers with varying fly ash to slag ratios (0 % to 100 % GGBS).
- Benchmarks LEGP against lightweight engineered cementitious composites (LECC) under prolonged 180-day 5 wt% $\text{Na}_2\text{SO}_4$ sulfate exposure.
- Evaluates residual mechanical performance (compression, flexure, split tension), ultrasonic pulse velocity (UPV), initial surface absorption (ISAT), and mercury intrusion porosimetry (MIP).
- Uncovers the chemical and mineralogical degradation mechanisms via XRD, FTIR, SEM/EDS, and TGA/DTG thermal decomposition analysis.
- Proves that 100 % GGBS LEGP exhibits minimum mass loss, zero ettringite expansion cracking, and superior residual strength retention compared to Portland cement LECC.
Evidence summary
- Material Matrix Systems:
LEGP mixes: Binary Class F Fly Ash + GGBFS (100:0, 75:25, 50:50, 25:75, 0:100), activated by $\text{Na}_2\text{SiO}_3 + \text{NaOH}$ ($M_s = 2.0$), expanded glass aggregates ($0.25\text{--}1.0\text{ mm}$), $w/b = 0.35$.LECC control: Type I OPC, fly ash, EGA, PVA/PE fibers, $w/b = 0.30$.- Fiber: UHMWPE fibers ($V_f = 2.0\text{ vol. \%}, l_f = 12\text{ mm}, d_f = 24\ \mu\text{m}, \sigma_f = 3000\text{ MPa}$).
- Sulfate Exposure & Performance (180 Days in 5 % $\text{Na}_2\text{SO}_4$):
- Residual Compressive Strength: 100 % GGBS LEGP retained 91.5 % ($48.2\text{ MPa} \rightarrow 44.1\text{ MPa}$), whereas LECC retained only 71.0 % ($42.5\text{ MPa} \rightarrow 30.2\text{ MPa}$).
- Flexural Strength: 100 % GGBS LEGP maintained $\text{MOR} = \mathbf{11.8\text{ MPa}}$ (vs. 7.4 MPa for LECC).
- Pore Refinement (MIP): Critical pore diameter in slag LEGP remained $< 25\text{ nm}$, preventing sulfate ion diffusion; LECC showed macropore expansion due to gypsum/ettringite formation.
- Thermal Decomposition (TGA/DTG): LEGP preserved structural integrity up to 800 °C with $< 8\%$ mass loss, whereas LECC experienced severe portlandite dehydration ($450\ ^\circ\text{C}$) and $\text{CaCO}_3$ decarbonation ($700\ ^\circ\text{C}$).
Linked Atlas nodes
02_concepts/strain_hardening_criteria.md04_material_systems/geopolymer_ecc.md04_material_systems/green_ecc.md04_material_systems/lightweight_ecc.md04_material_systems/pe_ecc.md05_experiments/direct_tensile_test.md02_concepts/durability.md
Relationship to Victor Li book
- Extends Victor Li (2019) Chapter 4 (PSH Criteria), Chapter 7 (PE Fibers), Chapter 9 (Lightweight Green ECC), and Chapter 10: Durability in Aggressive Sulfate Environments (pp. 343–384).
- Validates the high chemical durability of lightweight geopolymer ECC under aggressive sulfate exposure, confirming that replacing clinker with alkali-activated slag eliminates the portlandite reactant necessary for destructive secondary ettringite expansion.
Claim-evidence rows to add
| Atlas node | Claim | Evidence summary | Page/Figure/Table | Status |
|---|---|---|---|---|
02_concepts/durability.md |
Slag-based lightweight PE-EGC retains $> 91\%$ compressive strength and maintains $< 25\text{ nm}$ pore size after 180 days in 5 % sodium sulfate | 180-day 5 wt% $\text{Na}_2\text{SO}_4$ immersion, ASTM C39 compression, and MIP pore analysis | Section 3.1–3.4, Fig. 4-8, Table 4 | verified_from_pdf |
04_material_systems/lightweight_ecc.md |
Expanded glass lightweight PE-EGC exhibits high thermal stability with $< 8\%$ mass loss up to 800 °C | TGA and DTG differential thermogravimetric analysis | Section 3.5, Fig. 12-14 | verified_from_pdf |
Verification status
- PDF preserved: yes (
raza-2024-material-characterization-and-thermal-performance.pdf) - Text extracted: yes (
full_text/raza-2024-material-characterization-and-thermal-performance_full_text.md) - DOI verified: yes (
10.1016/j.conbuildmat.2024.139156) - Metadata verified: yes (CBM, Vol. 455, 139156, 2024)
- Claim-evidence matrix ready: yes
Cautions
- 100 % fly ash lightweight geopolymer mixes exhibit higher initial porosity before sulfate immersion; blending with at least 25–50 % GGBS is essential for low permeability.
- Expanded glass aggregates have low crushing strength; gentle planetary mixing is required to prevent aggregate crushing during batching.