Overview - ISO 14824-1:2012 (Grout for prestressing tendons - Basic requirements)
ISO 14824-1:2012 specifies the basic requirements for cement grouts used to fill and protect prestressing tendons in all types of structures (bridges, buildings, etc.). The standard covers acceptable materials, required grout properties, composition, batching/mixing tolerances, and the manufacturer’s declarations needed to ensure durable, corrosion-resistant tendon grouting.
Key topics and technical requirements
- Materials
- Cement: Portland or other cements permitted locally; cement type must be declared.
- Water: Must comply with ISO 12439.
- Admixtures: Allowed if proven suitable and used per manufacturer’s instructions.
- Additions: Silica fume permitted; other additions only as allowed by national practice and declared.
- Batching & mixing
- Materials batched by mass (water and liquid admixtures may be mass or volume).
- Accuracy: ±2% for cement/dry additions; ±1% for water/liquid admixtures.
- Mechanical mixing to achieve homogeneous, stable grout. Typical w/c ratio is below 0.45 (to be declared).
- Performance properties
- Chloride ≤ 0.10% by mass of cement; sulfate ≤ 4.5%; sulfide ≤ 0.04% for ordinary Portland cement.
- Sieve test: no lumps retained.
- Fluidity: limits specified (and must not change >20% from immediately after mixing to 30 min).
- Bleeding: ≤ 0.3% of initial volume after 3 h (wick-induced or inclined tube tests).
- Volume change: between −1% and +5% after 24 h at rest.
- Strength: ≥ 30 N/mm² at 28 days (or ≥ 27 N/mm² at 7 days if estimating 28-day strength).
- Setting time: initial set ≥ 3 h; final set ≤ 24 h.
- Density: fluid density to be measured and declared.
- Quality & conformity
- Manufacturer must document production control, incoming material checks, and nonconforming product handling.
- Initial type testing, audit testing and production control are required as part of conformity evaluation.
Applications and users
- Practical uses: grouting of post-tensioned and bonded tendons to protect steel from corrosion, ensure bond where required, transfer transverse compressive stresses, and prevent voids that trap water.
- Primary users:
- Structural and geotechnical engineers specifying tendon grouting for bridges, buildings and infrastructure.
- Grout manufacturers and suppliers preparing product declarations and packaging.
- Contractors and site teams responsible for batching, mixing and injection.
- Quality inspectors, third-party certifiers and testing laboratories.
Related standards
- ISO 14824-2 - Grouting procedures (suitability/inspection for projects)
- ISO 14824-3 - Test methods for grout properties
- ISO 22965-2 - Concrete constituents and production
- ISO 12439 - Mixing water for concrete
- ISO 9597 - Cement setting time and soundness
Keywords: ISO 14824-1:2012, grout for prestressing tendons, cement grout, tendon grouting, fluidity, bleeding, compressive strength, batching and mixing, grout specification.
