ISO 10406-3:2019

Overview

ISO 10406-3:2019 specifies standardized test methods for unidirectional carbon fibre‑reinforced polymer (CFRP) strips used as external-bonded reinforcement on concrete. The standard covers CFRP strips that consist of carbon fibre and a thermoset resin, are manufactured by the pultrusion method, have a high carbon fibre fraction (typically over 60%), and a thickness up to 3 mm. It defines specimen preparation, tensile testing procedures, accelerated laboratory light‑exposure (artificial weathering) tests and reporting requirements for evaluating tensile properties and durability of CFRP strips.

Key Topics and Requirements

• Scope and material limits: Applicable to pultruded CFRP strips, carbon-fibre fraction ≳60%, thickness ≤ 3 mm.
• Specimen geometry and preparation:
  • Test piece dimensions (examples in the standard): total length ≥ 200 mm; test length ≥ 100 mm; width typically 10–15 mm (if strip width ≤10 mm, specimen width equals strip width); anchorage length ≥ 50 mm; anchorage thickness 0.5–2 mm.
  • Use of bonded anchorage blocks/tabs at both ends to avoid premature bond failure.
  • Surface preparation (grinding/blasting) and adhesive bonding procedures for tabs.
  • Cutting accuracy: width tolerance within ±1 mm per 100 mm; use diamond or equivalent blades.
• Tensile testing:
  • Test machines shall conform to ISO 7500-1 and have capacity beyond expected specimen tensile capacity.
  • Use of precision strain gauges/extensometers mounted at the center of the test length to measure elongation and determine Young’s modulus and tensile strength.
  • Minimum number of specimens: no fewer than five for statistical relevance.
  • Procedures for calculating tensile capacity, tensile strength and Young’s modulus from load–strain curves.
• Durability / accelerated exposure:
  • Methods for accelerated artificial exposure (laboratory light sources), preparation of test plates, exposure periods and subsequent tensile tests.
  • Calculation of tensile strength retention rate (ratio of post‑exposure to pre‑exposure tensile strength) and visual inspection criteria.
• Reporting: Specified test report content including dimensions, test conditions, results and calculations.

Applications - Who Uses This Standard

• Structural and civil engineers specifying CFRP strengthening for concrete repair and strengthening projects.
• Manufacturers of CFRP strips and pultrusion facilities for quality control and product development.
• Testing laboratories and certification bodies performing material qualification, durability testing and compliance verification.
• Contractors and asset managers implementing external-bonded FRP retrofit systems for bridges, buildings and infrastructure.

Related Standards

• ISO 7500-1 - calibration and verification of testing machines (referenced).
• ISO 10406-2:2015 - FRP sheets test methods (companion part in the ISO 10406 series).

Keywords: ISO 10406-3:2019, CFRP strips, carbon fibre‑reinforced polymer, FRP reinforcement of concrete, tensile test methods, pultrusion, tensile strength retention, accelerated artificial exposure.