BS EN 12390-2:2019 defines strict, standardized procedures for making and curing hardened concrete specimens to ensure accurate, consistent strength test results. It mandates specific guidelines for mould preparation, compaction methods, and environmental controls for specimens during initial and final curing stages. For more details, visit BSI Knowledge
Based on UKAS laboratory assessment reports and industry experience, here are the top non-conformities related to BS EN 12390-2:2019:
| Mistake | Consequence | How to Avoid | |---------|-------------|---------------| | Using moulds out of tolerance (worn, warped) | Resulting cubes can be oversized (lower strength) or undersized (higher false strength). | Annual mould measurement log. | | Not covering specimens for first 24 hours | Surface drying → lower strength, cracking. | Use rigid plastic lids or cling film immediately. | | Incorrect rodding – too few strokes or bar of wrong diameter | Incomplete compaction → voids and low density. | Use rodding templates and trained operators. | | Water tank temperature not monitored or out of range (e.g., 23°C) | Faster strength gain – false pass for early age, but may also cause weaker late strength. | Continuous temperature logger with alarm. | | Tap water without lime | Surface softening → lower crush results by 5-15%. | Add calcium hydroxide powder to tank water. | | Testing specimens not demoulded flat – rocking on platens | Eccentric loading → variable results. | Check flatness before testing; cap or grind if necessary (per BS EN 12390-3). |
BS EN 12390-2:2019 provides the definitive framework for the preparation of concrete test specimens. Its strict requirements for temperature control and curing duration ensure that the construction industry has reliable data on concrete performance. Non-compliance with this standard typically results in invalid strength tests, posing significant risks to construction projects.
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
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
: Once demolded, specimens are typically cured in a water tank at
C or in a humidity-controlled chamber with relative humidity bs en 12390-2:2019
: 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
: 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?
BS EN 12390-2:2019: A Comprehensive Guide to Testing Hardened Concrete
The construction industry relies heavily on the quality and durability of concrete to ensure the structural integrity of buildings, bridges, and other infrastructure projects. One crucial aspect of concrete quality control is testing hardened concrete to determine its mechanical properties. This is where BS EN 12390-2:2019 comes into play. In this article, we will provide an in-depth look at the BS EN 12390-2:2019 standard, its significance, and the testing procedures for hardened concrete.
What is BS EN 12390-2:2019?
BS EN 12390-2:2019 is a British Standard (BS) and European Norm (EN) that outlines the testing methods for hardened concrete. Specifically, it covers the determination of the compressive strength of hardened concrete. The standard is published by the British Standards Institution (BSI) and is widely adopted across Europe and beyond.
Importance of Testing Hardened Concrete
Testing hardened concrete is essential to ensure that it meets the required strength and durability specifications. Compressive strength is a critical parameter in concrete quality control, as it directly affects the structural performance of concrete structures. The compressive strength test helps to:
BS EN 12390-2:2019 Testing Procedure
The BS EN 12390-2:2019 standard specifies the testing procedure for determining the compressive strength of hardened concrete. The test involves the following steps:
Test Specimen Requirements
According to BS EN 12390-2:2019, test specimens must meet specific requirements, including:
Factors Affecting Compressive Strength
Several factors can affect the compressive strength of hardened concrete, including:
Benefits of BS EN 12390-2:2019 Compliance
Compliance with BS EN 12390-2:2019 offers several benefits, including:
Conclusion
BS EN 12390-2:2019 is a critical standard for testing hardened concrete in the construction industry. By following the testing procedures outlined in this standard, construction companies can ensure that their concrete products meet the required compressive strength specifications. Compliance with BS EN 12390-2:2019 provides numerous benefits, including improved quality control, increased confidence, and compliance with regulatory requirements. As a result, it is essential for construction professionals to understand and implement the testing procedures outlined in BS EN 12390-2:2019 to ensure the structural integrity and durability of concrete structures.
BS EN 12390-2:2019 Testing Hardened Concrete: Making and Curing Specimens for Strength Tests
The BS EN 12390-2:2019 standard is a critical document for civil engineers, laboratory technicians, and construction professionals involved in concrete quality control. This European Standard specifies the methods for making and curing test specimens for strength tests on hardened concrete. Compliance with this standard ensures that concrete strength results are accurate, repeatable, and representative of the material's true potential. Understanding the Significance of the Standard
Concrete is a heterogeneous material, and its measured strength is highly sensitive to how it is handled in its plastic state and how it is treated during the early stages of hardening. BS EN 12390-2:2019 provides a rigorous framework to minimize variables during the sampling and preparation process. By standardizing the size of the molds, the compaction methods, and the temperature and humidity of the curing environment, the industry can compare results across different projects and regions with confidence. Scope and Application
This part of the EN 12390 series applies to specimens made from concrete with a maximum aggregate size of 40 mm or less. It covers the preparation of cubes, cylinders, and prisms. The standard is used both for specimens made in a laboratory setting and those made on-site to verify the quality of concrete being delivered to a structure. Essential Equipment Requirements
To adhere to the standard, specific equipment must be used. Molds must be made of a non-absorbent, rigid material that does not react with cement paste. They must be watertight and capable of maintaining their shape under the pressure of compaction. Common materials include steel, cast iron, and certain high-density plastics. Typically performed 24 hours ± 2 hours after casting
The standard also specifies the tools for compaction. Depending on the consistency of the concrete, this may include internal vibrators (poker vibrators), vibrating tables, or manual tamping rods. For manual compaction, the rod must be circular in cross-section, straight, and made of steel with a smooth finish. The Making of Test Specimens
The process begins with obtaining a representative sample of fresh concrete according to EN 12309-1. Once the sample is ready, the molds are prepared by applying a thin film of non-reactive release agent to the internal surfaces.
The concrete is placed in the molds in layers. The number of layers and the duration of vibration or number of tamps depend on the dimensions of the specimen and the workability of the mix. Over-vibration must be avoided as it can cause segregation, while under-compaction leads to voids that artificially lower the recorded strength. After compaction, the top surface is leveled using a trowel or float to create a smooth, flat finish. The Curing Process: A Critical Phase
Curing is perhaps the most vital step in the preparation of concrete specimens. BS EN 12390-2:2019 outlines strict parameters for both initial and long-term curing. Initial Curing
Specimens must remain in the molds for at least 16 hours but no longer than 3 days. During this time, they must be protected from shock, vibration, and dehydration. The temperature during this initial phase must be maintained between 20°C and 25°C in temperate climates, or higher in hot climates if specified. Covering the molds with plastic sheeting or wet burlap is a common practice to prevent moisture loss. Standard Curing
After removal from the molds (demolding), the specimens must be cured in water or in a mist room. If water curing is used, the specimens must be fully submerged in a tank. The water temperature must be maintained at a constant 20°C (± 2°C). If a mist room is used, the relative humidity must be kept above 95%. This controlled environment ensures that the hydration of the cement continues optimally, allowing the concrete to gain strength at a predictable rate. Marking and Documentation
Every specimen must be clearly and indelibly marked so that it can be traced back to its specific batch, location in the structure, and date of manufacture. Accurate record-keeping is a requirement of the standard, including details of the sampling procedure, the compaction method used, and the duration and conditions of the curing period. Differences Between Laboratory and Site Curing
While the standard primary focus is on "standard curing" to verify the potential strength of a mix design, it also acknowledges "site curing." Site-cured specimens are treated as closely as possible to the actual structure they represent. These are often used to determine when formwork can be safely removed or when post-tensioning can occur. However, site-cured results cannot be used for official compliance with the 28-day characteristic strength requirements unless specifically permitted. Conclusion
The BS EN 12390-2:2019 standard is a cornerstone of modern concrete technology. By following its detailed procedures for making and curing specimens, the construction industry ensures that the data used to make safety and structural decisions is robust and reliable. Whether you are a technician in a commercial lab or a site manager overseeing a major pour, a deep understanding of this standard is essential for maintaining the integrity of the built environment.
BS EN 12390-2:2019 does not work in isolation. It is part of a family:
| Standard | Title | Role | |----------|-------|------| | BS EN 12390-1 | Shape, dimensions, and tolerances of moulds | Specifies the moulds used in Part 2. | | BS EN 12390-3 | Compressive strength of test specimens | The test method after curing per Part 2. | | BS EN 12390-4 | Determination of compressive strength – non-destructive (rebound hammer) | Optional supplementary. | | BS EN 12350-4 | Fresh concrete – Degree of compactability | Helps determine compaction method for Part 2. | | BS 1881-108 | (Partly superseded) | Old UK standard – still referenced but not current. |
For anyone working in concrete testing, keeping the entire BS EN 12390 series on hand is essential.
| Equipment | Requirement | |-----------|-------------| | Moulds | Must be rigid, non-absorbent, and resistant to corrosion. Dimensional tolerance: ±0.5% of nominal size. Internal surfaces must have a roughness depth ≤ 3.2 µm. Moulds showing dents, warping, or wear beyond tolerance must be retired. | | Vibrating table | Frequency: 50 Hz ± 3 Hz; Amplitude: 0.5 mm ± 0.1 mm for cubes (0.8 mm for cylinders). Compliance must be verified annually. | | Compacting bar | Circular cross-section (e.g., 16 mm or 25 mm diameter depending on aggregate size), with a hemispherical tip. Mass and dimensions specified in the standard. | | Curing tank | Must maintain water temperature at 20°C ± 1°C (or ±2°C for lower grades). Water must be saturated with lime (to prevent leaching of calcium hydroxide from specimens). | | Humidity cabinet | For air curing: Must maintain 20°C ± 2°C and ≥95% relative humidity. |
Pro Tip: Many labs fail audits not due to bad technique but due to using moulds that are slightly out of square or have worn internal faces. Regular calibration and measurement of moulds is mandatory. Step 2: Preparation of Moulds
Testing hardened concrete — Part 2: Making and curing specimens for strength tests