Overview
ISO 23523:2021 - Test methods for discrete polymer fibre for fibre-reinforced cementitious composites (FRCC) - specifies standardized laboratory test methods for characterizing discrete polymer fibres used in cementitious matrices. The standard defines how to determine basic geometric, mechanical, thermal and durability properties of polymer fibres (e.g., aramid, polyamide, polyester, polyethylene, polypropylene, PVA) to support fibre certification (not quality control or field acceptance).
Key topics and requirements
ISO 23523:2021 covers test methods and reporting requirements for the following key properties:
The standard emphasizes properties of the smallest fibre unit dispersed in FRCC and excludes matrix-dependent properties such as bond strength, creep and fatigue.
Practical applications and users
ISO 23523:2021 is intended primarily for:
- Fibre manufacturers and suppliers - to certify and declare standardized fibre properties for civil engineering use
- Materials and testing laboratories - to perform reproducible laboratory measurements for certification
- Design and construction engineers - to compare fibre options and design FRCC mixes (e.g., selecting fibre length: 4–12 mm for mortar, ≥20 mm for concrete with coarse aggregate)
- Standards bodies and procurement teams - to define acceptance criteria and technical specifications in contracts and product standards
Using ISO 23523 test results helps engineers predict reinforcing performance (influence of tensile strength, initial modulus and aspect ratio), calculate fibre volume fraction (using density), and assess performance in fire scenarios (melting point) and alkaline environments.
Related standards
- ISO 1183‑1/2/3 - density determination methods for plastics
- ISO 11357‑3 - DSC for melting point determination
- ISO 2062 - textile fibre breaking force and elongation (related but not comprehensive for FRCC)
- ISO 19044, ISO 21022, ISO 21914 - test methods for composites (complementary context)
Keywords: ISO 23523:2021, polymer fibre test methods, FRCC, fibre diameter, tensile strength, initial modulus, melting point, alkaline durability, fibre certification.