Precasting Material has become a critical choice in modern construction due to its superior performance and wide range of applications, such as GRC, GRP, GRG and UHPC etc.. Through rigorous testing standards, we can comprehensively evaluate its essential properties, for instance compressive strength, flexural strength, and durability. These evaluations ensure reliability across various environments and provide safety assurances for engineering projects. This article introduces several major tests and explains the relevant standards in different regions.
Key Tests for Precasting Materials
- Tensile and Compressive Strength Tests
Objective: To verify the performance under tensile and compressive forces, ensuring structural integrity under different loads without cracking or deforming.
Brief Testing Process: Gradually apply tensile or compressive force to the sample using a universal testing machine until the sample ruptures.
- Flexural Strength Test
Objective: To assess the strength and flexibility under bending stress, demonstrating its applicability in various projects.
Brief Testing Process: Conduct a three-point bending test by placing the sample on two support points and applying force at the center until the sample fractures or deforms.
Objective: To simulate durability under extreme weather conditions, particularly in cold climates with repeated freeze-thaw cycles.
Brief Testing Process: Subject the sample to cycles of soaking, freezing, and thawing (typically 10–30 cycles) while observing for damage or strength loss.
- Water Absorption Test
Objective: To determine the material’s resistance to moisture in wet environments, critical for freeze-thaw resistance, waterproofing, and long-term durability. Generally the water absorption rate of GRC is about 8%, and that of UHPC is 2-3%.
Brief Testing Process: Dry the sample at 105°C to a constant weight, immerse it in water for 24 hours, and measure the weight gain to calculate the absorption rate.
- Fire Resistance Test
Objective: To verify the performance under high-temperature conditions, ensuring compliance with building codes and enhancing fire safety. GRC and GRG material is primarily composed of cement and glass fibers, which are inherently non-combustible materials. Therefore, with proper testing and verification, GRC can achieve zero flammable performance A1 grade by the indicator of inflammable and smoking development.
Brief Testing Process: Expose the sample to a standard fire source for a specified time and observe for combustion, smoke production, and heat release rate. The results determine the material’s fire rating.
Regional Standards
These standards help manufacturers and clients ensure GRC products’ reliability and safety, offering globally recognized testing methods to maintain product consistency across markets.
- International Standards
– ISO 10406-1: Provides test methods for fiber-reinforced concrete, including equipment and procedures to ensure international consistency.
– ISO 11999: Evaluates material stability under high-temperature and extreme conditions.
– GRCA Specification: A detailed guide for manufacturing and testing GRC products, published by the Glassfibre Reinforced Concrete Association (GRCA).
- European Standards
– EN 1170 Series: Focuses on various GRC test methods, including:
– EN 1170-1: Preliminary flexural strength test for GRC.
– EN 1170-5: Water absorption test to evaluate moisture resistance.
– EN 14649: Specifies GRC product requirements, including production processes, dimensional tolerances, and minimum strength.
- British Standards
– BS EN 1169: Covers performance and dimensional requirements for GRC construction components.
- American Standards
– ASTM C947: A three-point bending test to measure GRC’s flexural strength.
– ASTM C1185: Evaluates the physical properties of fiber-reinforced cement products, such as compressive and flexural strength.
– ASTM C666: Tests freeze-thaw durability, ensuring performance in cold climates.
- Chinese Standards
– GB/T 15231: Covers testing methods for glass fiber-reinforced cement products, including tensile and flexural strength.
– JG/T 139: An industry standard for GRC product production and quality control.
- Australian Standards
– Although no specific GRC standards exist, general concrete and building material standards such as AS 3600 (Concrete Structures) and AS/NZS 4859 (Thermal Insulation of Buildings) apply to GRC.
- Middle East and other countries
– These regions often adopt European or international standards (e.g., ISO) while adjusting for local building requirements and climate.
– GOST is the Russian State Standard, a set of technical standards managed by Rosstandart (Federal Agency on Technical Regulation and Metrology). Originally developed during the Soviet era, GOST standards are now widely used in Russia and other CIS (Commonwealth of Independent States) countries.
– Countries like the UAE may develop their own GRC testing standards based on building requirements, often adopting provisions similar to EN or ASTM standards.
Conclusion
The test results for precasting materials highlight their physical properties, including density, shrinkage, creep, freeze-thaw resistance, water resistance, thermal insulation, and fire resistance. These properties cold be influenced by factors such as cement type, water-cement ratio, mix design, fiber content, compaction, component shape, and curing methods etc.. Together, these factors determine the performance in practical applications.
By understanding these tests and standards, clients and professionals can make informed decisions about products, ensuring their suitability and safety in various construction projects. If there are any question, Conshell will be glad to be contacted anytime.