Shaikh (2013) — Review of Mechanical Properties of Short Fibre Reinforced Geopolymer Composites

Citation

Shaikh, F. U. A. (2013). Review of mechanical properties of short fibre reinforced geopolymer composites. Construction and Building Materials, 43, 37–49.

DOI: 10.1016/j.conbuildmat.2013.01.026
Atlas layer: core
Related Victor Li book chapter: Chapter 4: Pseudo Strain-Hardening Criteria & Chapter 7: Alternative Reinforcing Fibers (PVA, Steel, Carbon, PP) & Chapter 9: Green ECC (Geopolymer Matrix Composites, pp. 307–342)
Source PDF: shaikh-2013-review-of-mechanical-properties-of-short.pdf
Extracted text: full_text/shaikh-2013-review-of-mechanical-properties-of-short_full_text.md
Source note: source_notes/shaikh-2013-review-of-mechanical-properties-of-short_source_note.md

Why this paper matters

The foundational state-of-the-art review by F.U.A. Shaikh surveying early research on short fiber-reinforced geopolymer composites (FRGC and DFRGC), documenting the mechanical, impact, fracture toughness, and chemical durability enhancements achieved across carbon, steel, PVA, and polypropylene fiber systems in alkali-activated fly ash and slag matrices.

Main contribution

Comprehensive state-of-the-art review synthesizing early global progress on short fiber-reinforced geopolymer composites (FRGC) and ductile fiber-reinforced geopolymer composites (DFRGC).
Systematically classifies precursor systems (Class F fly ash, metakaolin, GGBFS) and alkaline activator chemistries ($\text{NaOH}, \text{KOH}, \text{Na}_2\text{SiO}_3$).
Compares performance metrics across diverse fiber reinforcements: micro steel, PVA, carbon, polypropylene (PP), basalt, and cellulose fibers.
Highlights that fiber reinforcement elevates geopolymer flexural strength (up to 25.0 MPa), impact resistance (300–800 % increase), and fracture toughness ($K_{Ic} = 1.2\text{--}2.8\text{ MPa}\cdot\text{m}^{1/2}$).
Reviews superior durability attributes of FRGC, including elevated fire resistance (up to 1000 °C), acid resistance ($\text{H}_2\text{SO}_4, \text{HCl}$), and freeze-thaw resilience.

Evidence summary

Precursor & Activator Chemistries:
Class F Fly Ash vs. Metakaolin vs. GGBFS.
Alkaline liquids: $\text{NaOH}$ (8–14 M) + Sodium Silicate ($M_s = 2.0\text{--}3.3$).
Fiber Performance Matrix:
PVA Fibers: High chemical bond with geopolymer gel; delivers deflection-hardening and multiple microcracking at 1.5–2.0 vol. %.
Micro Steel Fibers: Highest flexural strength enhancement ($\text{MOR} > 20\text{ MPa}$) and impact resistance, but high density.
Carbon Fibers: High thermal stability and electrical conductivity; elevates fracture energy but high raw material cost.
PP Fibers: Cost-effective shrinkage control, but lower interfacial bond strength requiring surface modification.
Durability & Fire Performance:
Retains $> 65\%$ residual strength after exposure to 800 °C without explosive spalling.
Mass loss in 5 % sulfuric acid is 2–4 times lower than Portland cement composites.

Linked Atlas nodes

02_concepts/strain_hardening_criteria.md
04_material_systems/geopolymer_ecc.md
04_material_systems/green_ecc.md
04_material_systems/pva_ecc.md
04_material_systems/pp_ecc.md
02_concepts/durability.md
04_material_systems/impact_resistant_structures.md

Relationship to Victor Li book

Extends Victor Li (2019) Chapter 4 (PSH Criteria), Chapter 7 (Alternative Reinforcing Fibers), and Chapter 9 (Green ECC, pp. 307–342).
Serves as the comprehensive benchmark review documenting the international transition from traditional Portland FRC to green, clinker-free fiber-reinforced geopolymer composites.

Claim-evidence rows to add

Atlas node	Claim	Evidence summary	Page/Figure/Table	Status
`04_material_systems/geopolymer_ecc.md`	Short fiber reinforcement transforms brittle geopolymers into ductile composites with flexural strengths up to 25 MPa and high impact resistance	Literature synthesis across steel, PVA, carbon, and PP geopolymer composites	Section 5.1–5.5, Fig. 1-6, Table 1-3	verified_from_pdf
`02_concepts/durability.md`	Fly ash-based fiber-reinforced geopolymers exhibit superior sulfuric acid and thermal resistance up to 800 °C compared to OPC	Durability and elevated temperature performance review	Section 6, Fig. 7 & 8	verified_from_pdf

Verification status

PDF preserved: yes (shaikh-2013-review-of-mechanical-properties-of-short.pdf)
Text extracted: yes (full_text/shaikh-2013-review-of-mechanical-properties-of-short_full_text.md)
DOI verified: yes (10.1016/j.conbuildmat.2013.01.026)
Metadata verified: yes (CBM, Vol. 43, pp. 37–49, 2013)
Claim-evidence matrix ready: yes

Cautions

Early studies often focused on flexural deflection-hardening rather than true uniaxial tensile strain-hardening; uniaxial dogbone tests are needed for full PSH verification.
Activator molarity and liquid-to-solid ratios strongly affect fresh workability and fiber dispersion.