Overview
ISO/TS 16774-4:2023 specifies a laboratory test method for adhesion on wet concrete surface of repair materials used to stop water-leakage cracks in underground concrete structures. The technical specification defines an indirect, qualitative (pass/fail) procedure that measures whether a repair material can maintain adhesion to a wet crack surface for a predetermined time while a known weight pulls on the bonded joint. Materials tested are classified into families with similar properties to enable relative comparisons.
Key Topics and Technical Requirements
- Test principle: Inject repair material into an artificial wet crack (two-part concrete/mortar specimen), clamp the upper part, let the lower part act as a weight and observe adhesion time.
- Pass/fail evaluation: Adhesion is judged qualitatively at a predetermined time and against a predetermined mass (example in Annex A: bottom part ~550 g ± 50 g).
- Apparatus: Adhesion tester with frame, clamp and removable mobile support plate; stopwatch; injector; water container.
- Specimen preparation:
- Two concrete/mortar parts separated by spacers to form a controlled crack width.
- Side sealing (silicone, tape) to prevent leakage during injection.
- Soak specimen underwater for a set period and inject repair material while surface remains wet.
- Ambient conditions: Recommended lab temperature (22 ± 2) °C and humidity (55 ± 5) %, with allowance for national variations (e.g., 16–27 °C ranges).
- Reporting and traceability: Detailed test report requirements include material identification (manufacturer, composition, storage), specimen data, ambient/test conditions, equipment, test duration and results, and declaration of conformity to ISO/TS 16774-4:2023.
- Classification objective: Group materials into families for comparative performance databases.
Applications and Who Uses This Standard
- Practical use: Provides a reference method to screen and compare the wet-surface adhesion of injection grouts, resins and other water-leakage repair materials intended for underground concrete cracks.
- Primary users:
- Materials manufacturers validating product adhesion to wet concrete.
- Laboratory test facilities performing quality control and R&D.
- Engineers and specifiers selecting repair materials for tunnels, basements, culverts and other subterranean concrete structures.
- Standards bodies and authorities developing national test methods.
- Benefits: Helps select materials that remain bonded under constantly wet/humid conditions, supporting durable leak repairs and safer underground infrastructure.
Related Standards
- ISO/TR 16475 - General practices for repair of water-leakage cracks in concrete structures (linked background and terminology).
- Other parts of the ISO/TS 16774 series - complementary test methods for water-leakage repair materials.
- ISO 1920-8 - referenced for standard drying/shrinkage conditions.
Keywords: ISO/TS 16774-4:2023, adhesion on wet concrete surface, test method, repair materials, water-leakage cracks, underground concrete structures, adhesion tester, artificial crack, pass/fail.