Overview
ISO 10406-4:2025 - Fibre-reinforced polymer (FRP) reinforcement of concrete - Test methods - Part 4: FRP grids - is an international standard that specifies standardized test methods for FRP grids used as reinforcement or pre-stressing tendons in concrete. The standard covers physical, mechanical, durability (alkali resistance), long-term mechanical and bond-property tests for FRP grids composed of fibres (aramid, basalt, carbon, glass) and resin matrices (thermosetting resins such as vinylester and unsaturated polyester, and thermoplastic resins such as polypropylene, polyamides, and PMMA). FRP grids in this document are defined as a rigid array of interconnected FRP bars (not textile meshes) and are intended for both rehabilitation of existing reinforced‑concrete (RC) structures and reinforcement of new construction.
Key topics and technical requirements
- Physical properties: test procedures for cross-sectional area, fibre volume fraction and coefficient of thermal expansion (CTE).
- Short-term mechanical tests: standardized tensile property testing (test pieces, equipment, procedures, calculations and reporting).
- Durability (alkali resistance): immersion procedures, assessment of appearance, mass change and residual tensile performance.
- Long-term mechanical behavior: methods for long-term relaxation, tensile fatigue strength and creep rupture (test pieces, frames, test methods and reporting).
- Bond properties: pull-out testing and single-lap shear tests to evaluate bond between FRP grids and concrete.
- Test documentation: each method includes specimen requirements, devices, calculation methods and test-report formats to ensure reproducible, comparable results.
Notable updates in this 2025 edition (from prior ISO 10406 parts) include the formal inclusion of thermoplastic resins, addition of fibre volume fraction and single-lap shear bond tests, and modifications to tensile, alkali and pull-off bond tests.
Practical applications and intended users
- Structural and civil engineers specifying alternative reinforcement solutions for concrete rehabilitation and new builds.
- Material manufacturers and suppliers developing or certifying FRP grids (glass, carbon, basalt, aramid).
- Independent testing laboratories performing standardized mechanical, durability and bond evaluations.
- Contractors, consultants and researchers who need consistent test data for design, durability assessment, and quality control.
- Code and specification writers integrating FRP reinforcement requirements into project documents.
Related standards
- ISO 10406 series (other parts address FRP bars, rods and other non‑traditional reinforcing materials) - full list available on the ISO website.
- Produced by ISO/TC 71 (Concrete, reinforced concrete and pre-stressed concrete); consult national standards bodies for implementation guidance.
Keywords: ISO 10406-4 2025, FRP grids, fibre-reinforced polymer, test methods, bond properties, alkali resistance, tensile fatigue, creep rupture, fibre volume fraction, thermoplastic resins.