Bsi bs en 12390 11 2015

— Part 6: Tensile splitting strength of test specimens — Part 7: Density of hardened concrete — Part 8: Depth of penetration of water under pressure — Part 9: Freeze-thaw resistance -

BSI Standards Publication

Testing hardened concrete

Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion

National foreword

This British Standard is the UK implementation of EN 12390-11:2015

It supersedes DD CEN/TS 12390-11:2010 which is withdrawn

The UK participation in its preparation was entrusted to TechnicalCommittee B/517/1, Concrete production and testing

A list of organizations represented on this committee can beobtained on request to its secretary

This publication does not purport to include all the necessaryprovisions of a contract Users are responsible for its correctapplication

© The British Standards Institution 2015 Published by BSI StandardsLimited 2015

ISBN 978 0 580 88230 2ICS 91.100.30

Compliance with a British Standard cannot confer immunity from legal obligations.

This British Standard was published under the authority of theStandards Policy and Strategy Committee on 31 August 2015

Amendments issued since publication

NORME EUROPÉENNE

English Version

Testing hardened concrete - Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion

Essais pour béton durci - Partie 11 : Détermination de la

résistance du béton à la pénétration des chlorures, diffusion

unidirectionnelle

Prüfung von Festbeton - Teil 11: Bestimmung des Chloridwiderstandes von Beton - Einseitig gerichtete

Diffusion

This European Standard was approved by CEN on 19 June 2015

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 Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the CEN-CENELEC Management Centre or to any CEN member

This European Standard exists 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, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania,

Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and United Kingdom

EUROPEAN COMMITTEE FOR STANDARDIZATION

C O M I T É E U R O P É E N D E N O R M A L I S A T I O N

E U R O P Ä I S C H E S K O M I T E E F Ü R N O R M U N G

CEN-CENELEC Management Centre: Avenue Marnix 17, B-1000 Brussels

Contents

European foreword 3

Introduction 5

1 Scope 6

2 Normative references 6

3 Term, definitions symbols and abbreviated terms 6

3.1 Terms and definitions 6

3.2 Symbols and abbreviated terms 7

4 Principle 8

5 Reagents and apparatus 8

5.1 Reagents 8

5.2 Apparatus 9

6 Preparation of specimens 10

6.1 Preparing sub-specimens 10

6.2 Conditioning and preparation of profile specimen for chloride testing 11

7 Procedure 13

7.1 Exposure conditions 13

7.2 Exposure method 14

7.3 Exposure period 14

7.4 Determination of initial chloride content (Ci ) 14

7.5 Profile grinding 15

7.6 Chloride analysis 16

8 Regression procedure and expression of results 16

9 Test report 19

10 Precision 19

Annex A (informative) Diffusion coefficients 21

Annex B (informative) Core test specimen 22

Annex C (informative) Typical equipment and procedure for vacuum saturation 23

Annex D (normative) Immersion method for large specimens 25

Annex E (informative) Guidance on the test procedure 26

Annex F (informative) Examples for calibration of the calculation procedure for regression analysis 28

Bibliography 33

European foreword

This document (EN 12390-11:2015) has been prepared by Technical Committee CEN/TC 104 “Concrete and related products”, the secretariat of which is held by DIN

This European Standard shall be given the status of a national standard, either by publication of an identical

text or by endorsement, at the latest by February 2016 and conflicting national standards shall be withdrawn

at the latest by February 2016

Attention is drawn to the possibility that some of the elements of this document may be the subject of patent rights CEN [and/or CENELEC] shall not be held responsible for identifying any or all such patent rights This document supersedes CEN/TS 12390-11:2010

In comparison to CEN/TS 12390-11:2010, the following changes have been made:

— In Clause 2, the normative references have been updated;

— In Clause 8, a minimum value of the coefficient of determination has been added and further guidance on the calculations has been added;

— In Clause 9, a graph and details of points included and excluded plus the coefficient of determination have been added;

— In Clause 10, Table 3 has been added;

— A new Annex E (informative) "Guidance on test procedure" has been added;

— A new Annex F (informative) "Examples for calibration of the calculation procedure for regression analysis" has been added;

— The Bibliography has been reviewed;

— The standard has been revised editorially

The drafting of this European Standard was delegated to CEN/TC 51(CEN/TC104)/JWG12/TG5

This test method is one of a series concerned with testing concrete At the behest of CEN, RILEM reviewed chloride testing methods [1] and this European Standard is based on their recommendations In addition, this European Standard draws on recommendations from the EU-project “Chlortest” 5th Framework Programme (GRD1-2002-71808/G6RD-CT-2002-00855) [2] immersion test recommendation as well as the Nordtest Method NT Build 443 Concrete, hardened: Accelerated Chloride penetration [3]

The series EN 12390, Testing hardened concrete includes the following parts:

— Part 1: Shape, dimensions and other requirements of specimens and moulds

— Part 2: Making and curing specimens for strength tests

— Part 3: Compressive strength testing of specimens

— Part 4: Compressive strength - Specification of testing machines

— Part 5: Flexural strength of test specimens

— Part 6: Tensile splitting strength of test specimens

— Part 7: Density of hardened concrete

— Part 8: Depth of penetration of water under pressure

— Part 9: Freeze-thaw resistance - Scaling (Technical Specification)

— Part 10: Determination of the relative carbonation resistance of concrete (Technical Specification)

— Part 11: Determination of the chloride resistance of concrete, unidirectional diffusion

— Part 13: Determination of the secant modulus of elasticity in compression

According to the CEN-CENELEC Internal Regulations, the national standards organizations of the following countries are bound to implement this European Standard: Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia, Finland, Former Yugoslav Republic of Macedonia, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom

Introduction

Steel reinforced concrete structures exposed to the ingress of chloride, either from seawater or other sources, need to be durable for at least the intended working life The possibility of reinforcement corrosion is significantly increased as the chloride level at the embedded reinforcement increases For this reason the chloride diffusivity or penetrability of the concrete is an important property to measure and this European Standard sets out a test method that may be applied to specimens cast or core specimens to assess the potential chloride resistance properties of a concrete mix

Specifications regarding the test procedure with core specimens are given in Annex B

28 d, a minimum of one day to prepare and condition the specimen and then 90 d to expose the specimen to the chloride solution

1 Scope

This European Standard is a method for determining the unidirectional non-steady state chloride diffusion and surface concentration of conditioned specimens of hardened concrete The test method enables the determination of the chloride penetration at a specified age, e.g for ranking of concrete quality by comparative testing Since resistance to chloride penetration depends on the ageing, including the effects of continual hydration, then the ranking may also change with age

The test procedure does not apply to concrete with surface treatments such as silanes and it may not apply to concrete containing fibres (see E.1)

2 Normative references

The following documents, in whole or in part, are normatively referenced in this document and are indispensable for its application For dated references, only the edition cited applies For undated references, the latest edition of the referenced document (including any amendments) applies

EN 12390-2, Testing hardened concrete - Part 2: Making and curing specimens for strength tests

EN 14629, Products and systems for the protection and repair of concrete structures - Test methods -

Determination of chloride content in hardened concrete

3 Term, definitions symbols and abbreviated terms

For the purposes of this document, the following terms, definitions, symbols and abbreviated terms apply

3.1 Terms and definitions

diffusion coefficient that takes into account simultaneous chloride binding

chloride diffuses through a thin specimen between two reservoirs of chloride solution, where one reservoir is at a higher concentration than the other This steady state chloride diffusion is not covered by this test method The steady-state chloride diffusion coefficient only reflects the ionic transport diffusion through concrete, as the concrete is unable to bind any more chloride ion

3.1.8

profile grinding

dry process grinding a concrete specimen in thin successive layers

3.1.9

vacuum saturated condition

specimen that is vacuum saturated with water

3.2 Symbols and abbreviated terms

Ci Initial chloride content, % by mass of concrete;

Cm,j Measured chloride content of concrete layer j, % by mass of concrete

Cr,j Chloride content of layer j calculated according to Formula (1) using the most suitable

combination of Cs and Dnss, % by mass of concrete

Cs Calculated chloride content at the exposed surface, % by mass of concrete

Cx Chloride content measured at average depth x and exposure time t, % by mass of

concrete

Dnss Non-steady state chloride diffusion coefficient, m2 s-1;

F Sum of squares of the residuals

FR Flow rate (flux) in mol m-2·s

sr Repeatability standard deviation

sR Reproducibility standard deviation

S Sum of squares

t Exposure time, seconds

u Variable of the integral with no units

x Depth below the exposed surface to the mid-point of the ground layer j, m;

z Adimensional parameter with no units

After 90 d of exposure, at least 8 parallel layers of the chloride exposed surface are ground off the profile specimen The acid-soluble chloride content of each layer and the average depth of the layer from the surface

of the concrete exposed to the chloride solution are determined The initial chloride content is determined by grinding a sample from the other sub-specimen and the acid-soluble chloride content determined

By non-linear regression analysis by least squares curve fitting, the surface chloride content (Cs) and the

non-steady state chloride diffusion coefficient (Dnss) are determined

Because of the high coefficient of variation, ~ 15 – 30 % for Dnss for the test, the number of specimens should

be increased until the required precision is achieved The results shall be reported separately and the average value

NOTE 1 The chloride diffusion coefficient varies with the age of the concrete and the period of exposure

NOTE 2 The diffusion test described in this European Standard is only valid for a constant initial chloride content

5 Reagents and apparatus

5.1 Reagents

Reagents of analytical quality shall be used

NOTE Unless otherwise stated ‘percent’ means percent by mass

5.1.1 Calcium hydroxide, Ca(OH)2.

5.1.2 Chloride exposure solution

5.1.2.1 Reference solution

Dissolve 30 g of analytical quality NaCl in 970 g of distilled or demineralized water having an electrical conductivity ≤ 0,5 mSm-1 at 20 °C to produce a 3 % by mass NaCl solution Store it in a clean container

5.1.2.2 Other exposure solutions

Where the concentration of the chloride exposure solution is other than that in 5.1.2.1, the concentration shall

be recorded and reported Where a different solution is used the composition of the solution shall be recorded and reported

NOTE 1 Natural and artificial seawater have been used to reflect the exposure of the construction works

accelerate the development of a chloride profile

5.1.3 Chloride ion diffusion proof two-component polyurethane or epoxy-based paint or other equivalent barrier system

5.1.4 Chemicals for chloride analysis, to EN 14629

5.1.5 Distilled or demineralized water, having an electrical conductivity ≤ 0,5 mSm-1

5.2 Apparatus

5.2.1 Water cooled diamond saw

5.2.2 Balance for weighing NaCl and water, capable of weighing to an accuracy of ± 0,1 g

5.2.3 Thermometer, capable of measuring to an accuracy of ± 1 °C

5.2.4 Temperature controlled chamber capable of keeping a temperature of 20 °C ± 2 °C

5.2.5 Where used, a polyethylene container with airtight lid for immersion of the profile specimen

The volume of the exposure solution shall exceed the volume of the specimen by not less than 12,5 ml per

cm2 of exposed surface A container may contain more than one specimen provided at least the minimum ratio of exposure solution to exposed surface is achieved The ratio of exposure solution to exposed surface shall be recorded and reported

During the test, the chloride concentration of the chloride exposure solution reduces and if the ratio of the volume of chloride exposure solution to exposure surface varies, the rate of reduction will vary with nominally identical concrete For this reason if a direct comparison of results from different specimens is required, the ratio of the volume of chloride exposure solution to exposed surface should be constant

5.2.6 Where used, pond to be attached to profile specimen The ponds shall have a constant diameter

and initial depth not less than 125 mm

5.2.7 Equipment for grinding off and collecting concrete powder in layers less than 2 mm deep,

capable of grinding a surface area of at least 40 cm2 and not grinding within 10 mm of the edge of the test area

5.2.8 Compressed air or air blower, to clean dust from specimen and equipment between grinding layers 5.2.9 Dust collecting bags

5.2.10 Equipment for chloride content testing, in accordance with EN 14629

5.2.11 Calliper, measuring to an accuracy of ± 0,1 mm

5.2.12 Vacuum container, capable of containing at least three specimens

5.2.13 Vacuum pump, capable of maintaining an absolute pressure of less than 50 mbar (5kPa) in the

container, e.g a water-jet pump

6 Preparation of specimens

6.1 Preparing sub-specimens

A specimen size shall be selected such that after cutting, the minimum dimension of the sub-specimens used

to determine a chloride profile are at least three times the nominal maximum aggregate size At least two specimens, either 100 mm diameter or more cylinders or 100 mm or more cubes, are cast and cured in a water filled bath with a temperature of 20 °C ± 2 °C in accordance with EN 12390-2, where the curing period is not less than 28 d

NOTE 1 The aim of the test will normally be to assess the potential resistance to chloride ingress for a concrete mix Where the concrete contains secondary cementing materials, such as fly ash or ground granulated blastfurnace slag, then

it may be appropriate to increase the minimum age at testing as it is known that chloride resistance may increase significantly at ages greater than 28 d

After at least 28 d of standard curing, each cylinder, cube or prism is cut into two sub-specimens using the water cooled diamond saw Cylindrical specimens are cut in the direction parallel to the flat surface and cubical specimens are cut in the direction parallel to the top (trowelled) surface as shown in Figure 1 The tested surface should be free of voids and visible cracks No dimension of the sub-specimens used to determine a chloride profile shall be less than three times the nominal maximum aggregate size One sub-specimen (called the ‘profile specimen’) is used to determine the chloride profile, and the initial chloride sub-specimen is used to determine the initial chloride content This initial chloride content is taken as being the chloride content of the cast concrete The adjacent sawn faces are used to determine these values

NOTE 2 Where a chloride profile is required that incorporates the effect of a formed surface then a formed surface from

a cube specimen may be specified as the surface for chloride exposure However, the results from such a procedure are difficult to interpret due to variations in the concentration of cement paste and chloride at the formed surface The use of this approach will be reported under sub-clause 9 m), as it is a non-standard test condition

Key

Figure 1 — Specimen preparation

After sawing, the sub-specimen to be used to determine the initial chloride content shall be placed in a close fitting sealed plastic bag or tested immediately

Where needed, the sub-specimens may be sawn to reduce their size to aid handling, but the sub-specimen for determining the chloride profile shall not have any dimension less than three times the nominal maximum aggregate size

6.2 Conditioning and preparation of profile specimen for chloride testing

6.2.1 Vacuum saturation of the profile specimens

After sawing the specimens, vacuum saturate the profile specimens with water Annex C shows a typical arrangement for vacuum saturation Place the profile specimens in the vacuum container and reduce the absolute pressure to a value between 10 mbar to 50 mbar (1 kPa to 5 kPa) within a few minutes of closing the container Maintain this absolute pressure for 3 h and then with the vacuum pump still running, fill the container with distilled or demineralized water until that all the profile specimens are completely immersed Maintain the absolute pressure for a further hour before allowing air to re-enter the container

Leave the profile specimens immersed in either this water or normal curing tank water until the process of surface sealing starts, see E.2

6.2.2 Sealing surfaces other than the surface to be exposed

Start the sealing within 24 h of completing the vacuum saturation All surfaces of the profile specimen except for the sawn face shall be sealed, see Annex D for an exception After sealing the surfaces, place the specimens in saturated calcium hydroxide solution for 18 h

ingress of chloride ions into the concrete is a pure unidirectional diffusion process and not a mixture of diffusion and other processes, e.g capillary suction

The requirement to seal the faces may be achieved in a number of ways The following techniques have established suitability

a) Sealing technique for immersion, ponding or inversion

NOTE 2 This usually takes between 2 h to 4 h

All faces except the face to be exposed to the chloride solution shall be coated with a layer of epoxy or polyurethane, paraffin wax, or equivalent making sure that the surface to be tested remains free of the coating material The coating material shall be applied and cured in accordance with the recommendations of the manufacturer

NOTE 3 Not all epoxy resins and polyurethanes are suitable for this application

b) Alternate sealing technique for ponding

This technique is only applicable to specimens that are to be ponded Dry the surfaces with a cloth to remove free water and wrap all faces except the face to be exposed to the chloride solution with insulating tape ensuring sufficient overlap of joints

6.2.3 Profile specimen for immersion

After storage in saturated calcium hydroxide solution, the specimen shall be transferred directly to exposure without surface drying A suitable arrangement is shown in Figure 2

20 mm less than the diameter of the specimen to allow the formation of a watertight seal

An alternative technique is to use a slightly larger tube and a rubber gasket between the tube and the sealed side of the specimen

7.1.1 Chloride exposure solution

Unless specified otherwise, the chloride exposure solution shall be a 3 % NaCl solution in accordance with 5.1.2.1 If the chloride exposure solution is other than the reference solution (see 5.1.2.2), it shall be reported The chloride exposure solution concentration after use shall be measured, recorded and reported

Where testing is related to the intended use in a specific exposure condition, the chloride exposure solution should reflect the anticipated exposure conditions taking into account the expected depletion of chloride (see E.3)

exposure solution has been selected so that it does not have to be replaced during a test lasting 90 d If a longer test period is required, it is advised to replace the chloride exposure solution at 91-day intervals

duration of the test In the normal test situation, the error introduced by assuming that the chloride concentration remains constant at the initial concentration is small

7.1.2 Exposure temperature

Where used, the temperature of the water bath for the immersion specimen, the temperature of the chloride exposure solution in the inversion method and the temperature of the chamber used to store the ponded specimen shall be maintained at 20 °C ± 2 °C and confirmed at least once per day and the mean and range over the duration of the test reported

7.2 Exposure method

7.2.1 General

The exposed (sawn) surface of the profile specimens shall be in direct and continuous contact with the chloride exposure solution either by immersion, ponding or inversion The age of the specimen when it is first exposed to the chloride exposure solution shall be recorded and reported

of entrapped air The chamber shall be sealed to prevent evaporation

7.3 Exposure period

The reference period of chloride exposure is 90 d

7.4 Determination of initial chloride content (C

)

Recover the initial chloride content specimen from the plastic bag A 1 mm layer shall be ground from the sawn surface of the initial chloride content specimen and discarded The same surface is then ground to

obtain a 20 g sample of dust for chloride analysis The acid-soluble chloride content is determined in

accordance with EN 14629 and expressed as percentage by mass of concrete and it is designated Ci

The initial chloride content may be determined from a single specimen per mix The content obtained shall be evaluated based on the mix design and the source of the materials

NOTE The user of the test results needs to be aware of the initial chloride content being unrealistically high or low

7.5 Profile grinding

After 90 d and within 2 h of removing the specimen from the exposure solution at least eight parallel layers of the profile specimen shall be dry ground where each layer gives a sample of not less than 5 g of dry concrete, and where layer 1 (surface layer) also has a thickness of not less than 1,0 mm The thickness of the layers shall be adjusted according to the expected chloride profile so that a minimum of 6 points covers the profile between the exposed surface and a depth where the chloride content is above the initial chloride content Table 1 gives recommended depth intervals for CEM I concrete and Table 2 depth intervals for concretes containing fly ash, ground granulated blastfurnace slag or silica fume Both tables are based on specimens that have been exposed for 28 d of standard curing followed by 90 d exposure to a chloride solution

existing structures

included in the profile) The criterion for a minimum of six points is to prevent the whole test being made invalid if one layer

is shown to be an outlier

NOTE 3 Further guidance on the procedure for profile grinding is given in reference [4]

After grinding, keep the remainder of the profile specimen in a close fitting sealed plastic bag until the profile

has been calculated If the chloride content in the deepest layer is more than Ci % by mass of concrete + 0,015 % by mass of concrete, grind off further layers so that a complete profile is established To ensure that a complete profile has been achieved, i.e the exposure solution has not penetrated the whole profile specimen, the last layer shall be at a depth of not less than the profile specimen thickness less 10 mm

The concrete specimens shall be dry ground and grinding shall be performed over a surface area of at least

40 cm2 and within a boundary that is 10 mm inside the boundary of the contact zone to avoid edge effects and disturbances from the coating

The profile specimen shall be securely fixed parallel to the grinder and a dust collection bag, e.g a plastic bag, shall be fixed in position to collect the dust Each layer should produce at least 5 g of dust After grinding each layer, clean the equipment and profile specimen surface of any residual dust with compressed air or an air blower, then measure the depth of the layer The depth of the layer is calculated as the mean of five evenly distributed measurements using the calliper rule

The concrete dust of each layer is collected in marked plastic bags to be analysed for chloride content Each bag shall be clearly marked with the sub-specimen reference, depth interval and date

Table 1 — Recommended depth intervals (millimetres) of profile grinding for CEM I concrete

Table 2 — Recommended depth intervals (millimetres) of profile grinding

for concrete containing ggbs, fly ash or silica fume

8 Regression procedure and expression of results

The chloride content of the first concrete layer, i.e the surface layer, is discarded for the regression analysis The chloride content of the second concrete layer (j = 2), is the first data point to be used in the regression analysis

Determine the concrete layer where the measured chloride content first reaches a value between Ci and

Ci + 0,015 %, with Ci equal to the initial chloride content of the concrete as determined according to 7.4 The

first concrete layer which demonstrates a chloride content Ci < C < Ci + 0,015 % provides the last data point (j = n) to be used in the regression analysis and it is called the ‘zero point’ If this point has not been found, deeper layers shall be ground from the profile specimen until the zero point has been reached Layers deeper than the zero point are excluded from the regression analysis as is the surface layer

In order to verify the suitability of the chosen mathematical model against the available dataset, i.e the measured chloride profile, the coefficient of determination (R2) shall be calculated

The coefficient of determination shall be more than 0,950 to be confident that the measured chloride profile is properly modelled by Formula (1) and confident in the output of the regression procedure expressed in terms

of Dnss and Cs

guidance on the situation where this requirement is not satisfied

a new part of the original sample ground

The calculated chloride content at the exposed concrete surface (Cs) and the non-steady state diffusion

coefficient (Dnss) shall be determined by fitting Formula 1 to the relevant data points by means of non-linear least squares regression analysis, as illustrated in Figure 5, and where the surface layer (j = 1) of the measured chloride profile is omitted

=

2 nss i

s i

t D

x erf C

C C

where

Dnss is the non-steady state chloride diffusion coefficient, m2 s-1;

erf is the error function defined in Formula 2, where

Values for erf z are given in widely available software packages

NOTE 3 It is not advised to use the values of Cs and Dnss to estimate chloride penetration for conditions other than those used in the test

which the critical chloride content is reached