ISO 21062:2020

Overview

ISO 21062:2020 - Corrosion of metals and alloys - specifies a laboratory method to determine and compare corrosion rates of steel reinforcement bars embedded in concrete exposed to simulated marine and coastal environments. The standard defines apparatus, materials, specimen preparation, test cycles, data recording, result calculation and reporting. It is intended for selection and comparison of corrosion‑resistant reinforcing steels and is not applicable to galvanized steel reinforcement. Annex A provides illustrative experimental results.

Key topics and technical requirements

• Simulation chamber and environment

  • Salt spray/mist system producing fine droplets; salt solution 3 % ± 0.2 % NaCl, initial pH 7 ± 0.5.
  • Controlled temperature range ≈ 5 °C to 30 °C.
  • Forced drying/ventilation system to restore environmental control.
  • Typical cycle: spray 60 min every 12 h, then ventilate 2 h.

• Test materials and specimen geometry

  • Reinforcing bars: 16 mm diameter; benchmark bar (0#) recommended B400DWR, length 395 mm ± 2 mm.
  • Test bars: numbered 1#, 2#, 3#, same length as benchmark.
  • Concrete: B30 (per ISO 22965‑1/2); cement recommended CEM II/A (42.5) per EN 197‑1.
  • Industrial salt added to concrete at 2.5 % of cement; recommended NaCl ≥ 94.5 %.
  • Specimens: 100 × 100 × 400 mm; protective concrete cover recommended 15 mm.
  • Reinforcing bar ends coated with epoxy per ISO 3673‑1, coating length 25 mm ± 1 mm.

• Preparation, testing and measurement

  • Reinforcing steel cleaning procedures (degreasing, acid immersion, rinse, solvent soak).
  • 28‑day curing of specimens (ISO 1920‑3); initial performance tests for mechanical and chemical properties per ISO 6935‑2.
  • Mass, dimension and strength measurements before and after exposure; removal of concrete (breaking of specimens) to extract bars.
  • Results expressed as mass loss rates, ratios vs. benchmark, and average rates for comparison.

Applications and users

• Applies to corrosion testing, material selection and durability design for marine and coastal reinforced concrete structures.
• Primary users:
  • Corrosion engineers and materials scientists
  • Structural and civil engineers specifying reinforcement for coastal infrastructure
  • Testing laboratories and quality control facilities
  • Reinforcing steel manufacturers and product developers
  • Asset owners and infrastructure managers assessing durability and service life

Related standards

• ISO 1920‑3, ISO 1920‑4 (concrete specimen making and strength)
• ISO 6935‑2 (steel for reinforcement)
• ISO 3673‑1 (epoxy resins)
• ISO 8407:2009 (removal of corrosion products)
• ISO 22965‑1/2 (concrete specification)
• EN 197‑1 (cement)

ISO 21062:2020 provides a reproducible, comparative laboratory method to quantify corrosion rates of embedded steel reinforcement under simulated marine exposure - a practical tool for durability design and material selection.