Concrete Admixtures CE Certification: EN 934 Standards Guide
Chemical admixtures, including water reducers, superplasticizers, set retarders, air-entraining admixtures and sprayed concrete accelerators, are placed on the market with CE marking under Regulation (EU) No 305/2011, the Construction Products Regulation (CPR). The relevant harmonised standards for these products are Parts 2, 3, 4 and 5 of the EN 934 series. This guide explains the structure of the standards, the characteristics declared in the Declaration of Performance (DoP), and the certification process under AVCP System 2+ for admixture manufacturers.
At a Glance
Admixtures covered by EN 934-2, EN 934-3, EN 934-4 and EN 934-5 are subject to Assessment and Verification of Constancy of Performance (AVCP) System 2+. The manufacturer determines the performance of each admixture type through testing in reference mixes, implements Factory Production Control (FPC), and prepares the Declaration of Performance (DoP). A Notified Body assesses the FPC system and issues a Certificate of Conformity of Factory Production Control.
Structure of the EN 934 Series
| Standard | Scope | Harmonised? |
|---|---|---|
| EN 934-1 | Common requirements for all admixtures | No (general requirements referenced by other parts) |
| EN 934-2 | Concrete admixtures | Yes |
| EN 934-3 | Masonry mortar admixtures | Yes |
| EN 934-4 | Admixtures for grout for prestressing tendons | Yes |
| EN 934-5 | Admixtures for sprayed concrete | Yes |
| EN 934-6 | Sampling, conformity control and evaluation of conformity | No (establishes rules for FPC and conformity control) |
In practice, admixture manufacturers should consider two parts of the series together: the product-specific standard (for example, EN 934-2) and EN 934-6, which establishes the Factory Production Control requirements.
Which Admixtures Are Covered by Each Part?
EN 934-2 – Concrete Admixtures: This standard classifies admixtures according to their functions and establishes specific requirements for each category. The main types include:
- Water-reducing / plasticizing admixtures
- High-range water-reducing / superplasticizing admixtures
- Water-retaining admixtures
- Air-entraining admixtures
- Set-accelerating and hardening-accelerating admixtures
- Set-retarding admixtures
- Water-resisting admixtures
- Combined-function admixtures (e.g., set-retarding / water-reducing admixtures)
- Viscosity-modifying admixtures
EN 934-3 – Masonry Mortar Admixtures: Long-term set-retarding admixtures and air-entraining / plasticizing admixtures for masonry mortars.
EN 934-4 – Grout Admixtures: Admixtures used to control the flowability, bleeding and volume change of grouts intended to fill tendon ducts in post-tensioned structures.
EN 934-5 – Sprayed Concrete Admixtures: Set accelerators (alkali-containing and alkali-free) used in tunnel and slope applications, together with other admixtures specifically developed for sprayed concrete.
Characteristics Declared in the Declaration of Performance (DoP)
Declarations of Performance for admixtures contain two main categories of information:
Homogeneity (identification) characteristics – the distinctive "fingerprint" of each admixture:
| Characteristic | Description |
|---|---|
| Appearance and colour | Conformity with the manufacturer's description |
| Dry material content | Declared value and tolerance range |
| Density (liquid admixtures) | Declared value and tolerance range |
| pH value | Declared value and tolerance range |
| Chloride ion content | Expressed as a percentage by mass; particularly important for reinforced concrete |
| Alkali content | Expressed as Na₂O equivalent |
| Corrosion behaviour | Absence of harmful effects on reinforcement corrosion |
Function-related performance characteristics – verification of the admixture's claimed effect through testing in reference mixes. For example, a superplasticizer is assessed for its water-reduction performance and increase in compressive strength; an air-entraining admixture for air content and air-void distribution; and a set retarder for the increase in initial setting time. These characteristics are determined by comparing mixes with and without the admixture, using the reference concrete or mortar specified in the relevant standard.
AVCP System 2+: Responsibilities of the Manufacturer and the Notified Body
Manufacturer:
- Demonstrates that each admixture type meets the requirements specified in the relevant standard tables through testing in reference mixes.
- Establishes and implements a Factory Production Control (FPC) system in accordance with EN 934-6.
- Tests samples taken during production according to the prescribed testing plan.
- Prepares the Declaration of Performance and affixes the CE marking.
Notified Body:
- Performs the initial inspection of the manufacturing plant and its Factory Production Control system.
- Conducts continuing surveillance, assessment and evaluation of FPC.
- Issues, restricts, suspends or withdraws the Certificate of Conformity of Factory Production Control.
Under System 2+, the Notified Body does not perform product-type testing or provide opinions on admixture formulations. The document commonly referred to as a "CE certificate" in the construction products sector is the Certificate of Conformity of Factory Production Control, issued following the successful completion of the certification process.
Key Factory Production Control Requirements for Admixture Manufacturing Plants
- Raw material control: Supplier documentation and incoming material inspections for polycarboxylate ethers, lignosulfonates, naphthalene sulfonates and other active substances.
- Batch identification: Definition of production batches and traceability of each batch.
- Identification testing: Verification of homogeneity characteristics such as dry material content, density, pH and chloride content for each batch or at specified intervals, with results compared against declared tolerances.
- Performance verification: Periodic verification of function-related properties, including water reduction, setting time and air content, using reference mixes.
- Product family approach: Grouping products based on the same active substance but differing in concentration into product families, and determining how these families are represented within the FPC system.
- Storage and shelf life: Measures to prevent sedimentation, freezing and separation, together with the declaration of shelf life on product labels.
- Labelling: Consistency between CE marking information on packaging and delivery documents and the Declaration of Performance.
Documentation Required Before Applying for Certification
An admixture manufacturer applying for Factory Production Control (FPC) certification is expected to have the following information and records available before the initial inspection:
- A list of admixtures to be included in the certification scope, specifying the relevant EN 934 part and table number for each product.
- Product-type determination test reports for each admixture type, including reference mix test results.
- Declared values and tolerance ranges for homogeneity characteristics.
- Documented FPC procedures covering raw material acceptance, manufacturing, batch identification, testing plans and frequencies, non-conforming products and corrective actions.
- A list of testing and measuring equipment, together with calibration records.
- Information about the manufacturing facility and the relevant agreement where subcontracted manufacturing is involved.
- Draft Declarations of Performance and examples of product labels.
Example of a CE Marking Label
Illustrative CE marking label – Concrete Admixture
CE · 3228
Example Construction Chemicals Ltd., [address]
26
DoP No.: EX-CA-001
EN 934-2:2009+A1:2012
High-range water-reducing / superplasticizing admixture for concrete (Tables 3.1 and 3.2)
Chloride ion content: ≤ 0.1% · Alkali content: ≤ [declared value] · Corrosion behaviour: no harmful effect · Compressive strength: [declared value] · Water reduction: [declared value] · Dry material content: [declared value ± tolerance]
For illustrative purposes only.
Common Mistakes
- Declaring an admixture with an unverified function (e.g., both superplasticizing and set-retarding properties).
- Declaring homogeneity characteristics without specifying the applicable tolerance ranges.
- Failing to repeat initial type tests or notify the Notified Body following changes to the formulation.
- Failing to include the actual manufacturing facility within the FPC certification scope when production is subcontracted.
- Declaring a masonry mortar admixture under EN 934-2 instead of the applicable EN 934-3 standard.
Frequently Asked Questions
EN 934 is a series of European standards specifying the technical characteristics, performance requirements and conformity assessment provisions for chemical admixtures used in concrete, mortar and grout. EN 934-2 covers concrete admixtures, EN 934-3 covers masonry mortar admixtures, EN 934-4 applies to admixtures for grout used in prestressing tendon ducts, and EN 934-5 covers sprayed concrete admixtures. EN 934-1 establishes common requirements, while EN 934-6 addresses sampling and conformity control procedures.
CE marking is mandatory for products placed on the market within the scope of the relevant harmonised standards of the EN 934 series. These products require Factory Production Control (FPC) certification by a Notified Body under Assessment and Verification of Constancy of Performance (AVCP) System 2+. However, not every chemical admixture automatically falls within the scope of EN 934. The applicable standard must be determined by evaluating the product's intended use and technical characteristics.
Manufacturers of concrete, mortar or grout admixtures must first identify the applicable part of EN 934 and the relevant admixture category. They must then perform or commission the performance tests required by the applicable standard and establish a Factory Production Control (FPC) system. Under AVCP System 2+, the manufacturer applies to an appropriately designated Notified Body. If the assessment of the manufacturing facility and FPC system confirms conformity, a Certificate of Conformity of Factory Production Control is issued. The manufacturer subsequently prepares the required Declaration of Performance (DoP) and affixes the CE marking to the product.
The application generally involves a list of admixtures to be certified, the applicable EN 934 standards, product-type determination test reports, declared performance values and tolerances, production control procedures, quality control records and calibration certificates for testing equipment. Draft Declarations of Performance, product labels and subcontract manufacturing agreements, where applicable, may also be required. The exact documentation requirements depend on the characteristics of the manufacturing facility and the product groups included in the certification scope.
The cost of CE certification varies depending on the characteristics of the manufacturing facility, the types of admixtures included in the certification scope, required testing and assessment activities. The possibility of evaluating multiple admixture types within a single application may also affect the overall cost. In addition to initial certification, ongoing surveillance activities should be taken into account. Manufacturers may request a quotation from Sertifike for an assessment based on their specific facility and certification requirements.
The certification timeline depends on whether the necessary performance tests have been completed, the readiness of the Factory Production Control system, audit scheduling and the time required to resolve any identified nonconformities. The process may proceed more efficiently for manufacturing facilities with completed test reports and well-established production control records. Audit and certification activities are planned following a review of the application scope.
No. An FPC certificate is issued for the manufacturing facility and the products included within its certification scope. Multiple admixture types manufactured at the same facility may be evaluated under a single application. The certificate identifies the relevant products or product families covered. However, whether different admixtures can be assessed within the same certification scope depends on their technical characteristics, manufacturing conditions and the requirements of the applicable standards.
Under AVCP System 2+, testing to determine the performance of the product type is the manufacturer's responsibility. Tests may be conducted in the manufacturer's own laboratory or by an external laboratory, provided the necessary technical competence and testing conditions are met. For example, the water-reducing performance of a superplasticizer is determined through comparative testing using the reference mixes specified in the relevant standard. The Notified Body assesses whether these tests and their associated records are appropriately managed within the Factory Production Control system.
Not every formulation change automatically invalidates the certificate. However, changes that may affect the product's declared performance may require reassessment. This may involve repeating relevant performance tests and updating FPC records and the Declaration of Performance. The change must be reported to the Notified Body so that its implications for the certification scope can be evaluated.
EN 934-6 establishes the rules for sampling, conformity control and conformity assessment of admixtures for concrete, mortar and grout. Product-specific standards, including EN 934-2, EN 934-3, EN 934-4 and EN 934-5, refer to this part for requirements related to production control. Accordingly, EN 934-6 serves as a complementary standard that manufacturers must consider when establishing and maintaining their Factory Production Control systems.
The company that places the product on the market under its own name or trademark and affixes the CE marking assumes the responsibilities of the manufacturer under the applicable legislation. However, the facility where the admixture is physically manufactured must also be included within the scope of the FPC assessment. The subcontract manufacturing arrangement must be defined through agreements, with clear allocation of production and quality control responsibilities and appropriate traceability records. The application and certification scope are evaluated on this basis.
The CE marking and its accompanying information must be affixed to the product, its label or its packaging in accordance with the applicable legislation. Where this is not possible, the information may be provided in documents accompanying the product. For bulk deliveries, the required information may appear on delivery notes or shipping documents. The performance information accompanying the CE marking must be consistent with the Declaration of Performance (DoP). For products subject to AVCP System 2+, the identification number of the relevant Notified Body must also accompany the CE marking.
