Bs En 12390-2:2019 [upd] – Easy & Original

BS EN 12390-2:2019 the British and European standard that defines the procedures for making and curing concrete specimens for strength tests

. By standardizing how test cubes, cylinders, and prisms are handled, it ensures that the physical properties of the hardened concrete are measured accurately and consistently across different construction projects. Scope and Purpose

The standard provides a rigorous framework for preparing specimens used primarily for compressive and flexural strength testing. It covers the entire lifecycle of a test specimen, including: Preparation : Using non-reactive release agents to prevent sticking. : Layering concrete based on consistency. Compaction

: Prescribing specific mechanical (vibrating tables, internal vibrators) or hand methods (compacting rods).

: Establishing precise temperature and moisture requirements. Key Technical Procedures bs en 12390-2:2019

Adhering to these steps is critical, as minor deviations can lead to significant variations in reported strength. Compaction

: The standard allows for multiple methods but warns against over-vibration, which can cause the loss of entrained air and lead to segregation. For hand compaction, it typically suggests 25 strokes per layer to remove entrapped air without disturbing entrained air. Initial Curing

: Specimens must remain in their molds for at least 16 hours but no more than three days at a temperature of

C. They must be protected from shock, vibration, and moisture loss (e.g., covered with polyethylene sheeting). Final Curing BS EN 12390-2:2019 the British and European standard

: Once demolded, specimens are typically cured in a water tank at

C or in a humidity-controlled chamber with relative humidity

: When moving specimens to a laboratory, they must be protected from dehydration and temperature extremes using wet sand, sawdust, or sealed plastic bags. Significance in Construction The 2019 version supersedes the earlier 2009 edition and aligns with the broader EN 12390 series

for hardened concrete testing. Its implementation is vital for: Quality Control the humidity must be $\ge 95%$

: Verifying that the concrete delivered to a site meets the specified design strength.

: Ensuring structural integrity by identifying substandard batches before they become critical failures. Traceability

: Requiring detailed reporting of sampling, compaction, and curing conditions to maintain accountability.

For professionals like civil engineers and laboratory technicians, following the BS EN 12390-2:2019

standard is not just a regulatory requirement but a fundamental practice for building durable and safe infrastructure. comparative breakdown of the specific changes between the 2009 and 2019 versions?

A. Standard Curing (Water Curing) – for Conformity Testing

• Environment: Fully immersed in lime-saturated water (or water stored in a sealed, damp cabinet at ≥95% RH).
• Temperature: 20°C ± 1°C (for concrete with specified strength ≥80 MPa) or 20°C ± 2°C (for lower grades). The 2019 version introduces stricter control for high-strength concrete because it is more sensitive to temperature variations.
• Water quality: The water must be changed periodically to maintain saturation with calcium hydroxide. Use of tap water alone (without lime) can leach out cement paste, weakening the surface of the specimen and leading to false low results.

Step 2: Preparation of Moulds

• Clean the mould thoroughly.
• Apply a thin, even layer of release agent (mould oil). Avoid puddles, which cause surface pitting.
• Ensure the mould is assembled tightly – loose joints cause leakage and honeycombing.

A. Moulds and Compaction

• Mould Material: Moulds must be rigid, watertight, and non-absorbent. They are typically made of steel or cast iron, though plastic moulds are permitted if they meet specific rigidity requirements.
• Compaction: Specimens must be fully compacted. The standard permits two methods:
  • Vibration: Using a vibrating table or poker vibrator.
  • Hand Tamping: Using a tamping bar or hammer, provided the concrete is sufficiently workable.
  • Crucial Note: Over-compaction can cause segregation (settling of aggregates), while under-compaction leaves honeycombing (voids), both of which lead to inaccurate strength readings.

D. Subsequent Curing (Until Testing)

Once demoulded, the specimens enter the main curing phase. This ensures hydration continues uninterrupted.

• Water Curing: The preferred method is submersion in water. The water temperature must be maintained at $20 \pm 2^\circ C$. The water should be changed regularly to prevent the build-up of lime, which can alter the curing environment.
• Storage: If stored in air (less common for standard strength tests), the humidity must be $\ge 95%$, and the temperature must remain at $20 \pm 2^\circ C$.