prEN 196-13

• Abstract:

  This document specifies the apparatus and procedure for determining the effective alkali content of cements and other hydraulic binders. The method determines the effective alkali content after 28 days of hydration by extracting pore water from cement stone and determining the concentration of sodium and potassium (method A) or hydroxyl ions in the solution (method B).

• Status: Not Published
• Publication Date: 24-May-2028
• ICS: 91.100.10 - Cement. Gypsum. Lime. Mortar
• Technical Committee: CEN/TC 51 - Cement and building limes
• Drafting Committee: CEN/TC 51/WG 15 - Revision of methods of testing cement
• Current Stage: 4020 - Submission to enquiry - Enquiry
• Start Date: 06-Aug-2026
• Due Date: 11-Feb-2027
• Completion Date: 06-Aug-2026
• Ref Project: oSIST prEN 196-13:2026 - Methods of testing cement - Part 13: Effective alkali content

prEN 196-13 is a draft European Standard from CEN for measuring the effective alkali content of cements and other hydraulic binders. It specifies the apparatus and procedure for a 28-day surplus water extraction test, then determines effective alkali either by sodium and potassium measurement in Method A or by hydroxyl ion titration in Method B. The document is intended for laboratories and technical staff who need a comparable result reported as effective sodium oxide equivalent.

What does prEN 196-13 specify?

prEN 196-13 specifies how to determine the effective alkali content of cements and other hydraulic binders after 28 days of hydration. The method uses pore-water extraction from cement stone and then measures either sodium and potassium ions or hydroxyl ions in the extracted solution.

The document is organized into:

• Scope
• Normative references
• Reagents
• Apparatus
• Effective alkalis from SWE test (surplus water extraction method)
• Test report
• Precision
• Bibliography

Clause 6 contains the actual test principle, preparation, analysis, calculation, reporting and precision statements. That is the part readers will use when setting up or checking a laboratory method.

What are the key requirements of prEN 196-13?

prEN 196-13 is built around a surplus water extraction method (SWE) followed by either elemental analysis or titration. In practice, a lab prepares cement paste with a fixed water-to-cement ratio, stores it under controlled conditions, then analyzes the liquid phase above the paste.

Sample preparation and storage

Clause 6.2 requires freshly boiled deionized water, 100.0 g of water and 100.0 g of cement, mixed thoroughly for three minutes in a wide-neck bottle and sealed airtight. The bottle is stored upright at 20.0 °C ± 2.0 °C for 28 days ± 8 h. This matters because the hydration period and storage conditions affect the alkali content measured in the pore water.

The text also warns to protect the sample from atmospheric CO2. That is important because carbonation can change the hydroxyl-ion result, especially for Method B.

Extraction and filtration

After storage, the liquid above the cement paste is extracted and filtered through a 0.45 µm filter made of hydrophilic PTFE. The filtrate is then kept protected from atmospheric CO2, for example under argon or nitrogen, unless it is analyzed immediately. This keeps the extracted solution representative of the cement paste.

Method A - sodium and potassium

Clause 6.3.1 measures sodium and potassium by flame photometric detection based on EN 196-2, or according to EN 14911. Other methods are allowed if they give similar results. Calibration solutions are prepared from sodium and potassium stock solutions, buffer solution and dilute hydrochloric acid, then used to build a calibration curve. For the reader, this means the laboratory must control calibration carefully and use a method that gives comparable sodium and potassium concentrations.

Method B - hydroxyl ions

Clause 6.3.3 offers an alternative based on titrating hydroxyl ions with 0.05 mol/l hydrochloric acid and methyl orange indicator. A potentiometric titration is also stated to give equivalent results. The acid factor must be checked with sodium carbonate. Duplicate determinations are required, and if the two results differ by more than 5% relative, a third determination is made. The reported hydroxyl-ion concentration is the mean, rounded to the nearest whole number.

Calculation and reporting

Both methods convert the analytical result to effective sodium oxide equivalent, expressed as Na2Oeq,eff, and reported with two decimal places. Clause 6.4 lists the test report items: reference to the document, test dates, cement name and origin, test method used, measured ion concentration, effective alkali content, and any deviations from the method.

Precision

Clause 6.5 gives relative precision values of 2% for repeatability and 5% for reproducibility. These figures help users judge whether two results are close enough to be considered equivalent.

What changed in prEN 196-13 from the previous edition?

This draft identifies itself as prEN 196-13 and as a new part in the Methods of testing cement series.

Which standards are used with prEN 196-13?

• EN 196-2 - used for the chemical-analysis approach in Method A and for calibration-curve construction.
• EN 14911 - gives an alternative method for determining dissolved sodium and potassium by ion chromatography.

EN 196-7 is listed in the bibliography and is relevant to sampling and preparation of cement samples, but it is not a normative reference.

What does the prEN 196-13 document contain?

prEN 196-13 contains a practical laboratory method, not just a definition of the result. It gives the reagent list, required apparatus, and a step-by-step SWE procedure for making and storing the cement paste sample.

It also includes the analytical setups for Method A and Method B, including the calibration solutions in Table 1, the titration approach, and the calculation expressions used to convert measured concentrations into effective sodium oxide equivalent. The document finishes with the required report contents and precision data so users can compare results between laboratories.

SLOVENSKI STANDARD
01-oktober-2026
Metode preskušanja cementa - 13. del: Učinkovita vsebnost alkalij
Methods of testing cement - Part 13: Effective alkali content
Prüfverfahren für Zement – Teil 13: Effektiver Alkaligehalt
Méthodes d'essais des ciments - Partie 13 : Teneur en alcalins effectifs
Ta slovenski standard je istoveten z: prEN 196-13
ICS:
91.100.10 Cement. Mavec. Apno. Malta Cement. Gypsum. Lime.
Mortar
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
August 2026
ICS 91.100.10
English Version
Methods of testing cement - Part 13: Effective alkali
content
Méthodes d'essais des ciments - Partie 13 : Teneur en Prüfverfahren für Zement - Teil 13: Effektiver
alcalins effectifs Alkaligehalt
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee
CEN/TC 51.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.

This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.

Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.

EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2026 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 196-13:2026 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
1 Scope . 5
2 Normative references . 5
3 Terms and definitions . 5
4 Reagents . 6
4.1 Distilled water . 6
4.2 Dilute hydrochloric acid (1+9): mix 9 volumes of water with 1 volume of concentrated
hydrochloric acid. . 6
4.3 Hydrochloric acid 0,05 mol/l, p.a . 6
4.4 sodium stock solution 1 000 mg/l: Dissolve (2,542 ± 0,001) g of sodium chloride in water
in a 1000 ml volumetric flask an make up to the mark. Commercially available solution can
also be used. . 6
4.5 potassium stock solution 1 000 mg/l: Dissolve (1,907 ± 0,001) g of potassium chloride in
water in a 1 000 ml volumetric flask an make up to the mark. Commercially available
solution can also be used. . 6
4.6 Buffer solution: Dissolve 50 g of caesium chloride and 250 g of aluminium nitrate
(Al(NO ) .9H O) in water and make up to 100 ml. . 6
3 3 2
4.7 Methyl orange indicator (dimethylaminoazobenzene p-sodium sulfonate): Dissolve
(0,020 ± 0,002) g of methyl orange in water and make up to 1 000 ml. . 6
4.8 Sodium carbonate (Na CO ) dried to constant mass at (250 ± 10) °C . 6
2 3
5 Apparatus . 6
5.1 Balance, analytical balance, capable of weighing to an accuracy of ± 0,01 g. 6
5.2 Climatic cabinet or chamber, capable of maintaining a temperature of (20,0 ± 2,0) °C . 6
5.3 Suction bottle, 250 ml . 6
5.4 Microlitre pipette, 1 ml to 5 ml or syringe with needle . 6
5.5 Filter with a filter pore size of 0,45 µm. Filter made of hydrophile Polytetrafluoroethylene
(PTFE) . 6
5.6 Volumetric pipette, 100 ml . 6
5.7 Volumetric burette, 50 ml . 6
5.8 Titration device (e.g. titrator) . 6
5.9 Argon or N gas . 6
5.10 Wide-neck bottle, made of Polyethylen (PE), Polypropylen (PP), Polyvinylchlorid (PVC) or
equivalent with screw cap (250 ml or 300 ml) . 6
5.11 Glass rod . 6
6 Effective alkalis from SWE test (surplus water extraction method) . 6
6.1 Principle . 6
6.2 Preparation of surplus water by extraction method (SWE) . 7
6.3 Determination of effective alkali content . 7
6.3.1 Method A: Determining the concentration of sodium and potassium . 7
6.3.2 Calculation . 8
6.3.3 Method B: determining the hydroxyl ion concentration (alternative) . 9
6.4 Test report . 10
6.5 Precision . 10
6.5.1 Repeatability . 10
6.5.2 Reproducibility . 10
Bibliography . 11
EN 196-13:2026 (E)
European foreword
This document (prEN 196-13:2026) has been prepared by Technical Committee CEN/TC 51 “Cement and
building limes”, the secretariat of which is held by NBN.
This document is currently submitted to the CEN Enquiry.
1 Scope
This document specifies the apparatus and procedure for determining the effective alkali content of
cements and other hydraulic binders. The method determines the effective alkali content after 28 days of
hydration by extracting pore water from cement stone and determining the concentration of sodium and
potassium (method A) or hydroxyl ions in the solution (method B).
2 Normative references
The following documents are referred to in the text in such a way that some or all their content constitutes
requirements of this document. For dated references, only the edition cited applies. For undated
references, the latest edition of the referenced document (including any amendments) applies.
EN 196-2, Methods of testing cement — Part 2: Che
...