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BRITISH STANDARD BS EN 146292007 Products and systems for the protection and repair of concrete structures Test s Determination of chloride content in hardened concrete The European Standard EN 146292007 has the status of a British Standard ICS 91.100.30 BS EN 146292007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 30 April 2007 BSI 2007 ISBN 978 0 580 50528 7 National foreword This British Standard was published by BSI. It is the UK implementation of EN 146292007. The UK participation in its preparation was entrusted by Technical Committee B/517, Concrete, to Subcommittee B/517/8, Protection and repair of concrete structures. A list of organizations represented on B/517/8 can be obtained on request to its secretary. This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. Compliance with a British Standard cannot confer immunity from legal obligations. Amendments issued since publication Amd. No. DateComments 标准分享网 w w w .b z f x w .c o m 免费下载 w w w . b z f x w . c o m EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 14629 March 2007 ICS 91.100.30 English Version Products and systems for the protection and repair of concrete structures - Test s - Determination of chloride content in hardened concrete Produits et systmes pour la protection et la rparation des structures en bton - Mthodes dessais - Mesurage du taux de chlorure dun bton durci Produckte und Systeme fr den Schutz und die Instandsetzung von Betontragwerken - Prfverfahren - Bestimmung des Chloridgehaltes von Festbeton This European Standard was approved by CEN on 7 September 2006. 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 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 Management Centre has the same status as the official versions. CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre rue de Stassart, 36 B-1050 Brussels 2007 CENAll rights of exploitation in any and by any means reserved worldwide for CEN national Members. Ref. No. EN 146292007 E w w w . b z f x w . c o m EN 146292007 E 2 Contents Page Foreword..............................................................................................................................................................3 Introduction.........................................................................................................................................................4 1 Scope ......................................................................................................................................................5 2 Normative references............................................................................................................................5 3 Materials and apparatus........................................................................................................................5 3.1 Chemicals...............................................................................................................................................5 3.2 Apparatus ...............................................................................................................................................5 4 Test procedure .......................................................................................................................................6 4.1 Sampling.................................................................................................................................................6 4.2 Grinding..................................................................................................................................................7 4.3 Chemical analysis..................................................................................................................................7 5 Test report..............................................................................................................................................9 Bibliography......................................................................................................................................................10 标准分享网 w w w .b z f x w .c o m 免费下载 w w w . b z f x w . c o m EN 146292007 E 3 Foreword This document EN 146292007 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 September 2007, and conflicting national standards shall be withdrawn at the latest by September 2007. 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. It has been prepared by sub-committee 8 “Products and systems for the protection and repair of concrete structures“ Secretariat AFNOR. This European Standard is one of a series dealing with products and systems for the protection and repair of concrete structures. It describes a for determining the chloride content of hardened concrete. 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, Cyprus, Czech Republic, Denmark, Estonia, Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal, Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and the United Kingdom. w w w . b z f x w . c o m EN 146292007 E 4 Introduction Steel reinforcement in concrete may be at risk of corrosion if the concrete is contaminated by chlorides. ENV 1504-9 defines the principles for protection and repair of concrete structures which have suffered or may suffer damage or deterioration and gives guidance on the selection of products and systems which are appropriate for this intended use. EN 1504-10 requires that the concentration of chlorides be considered when decisions about the removal of concrete are made. To establish whether there is a risk of corrosion of the steel reinforcement due to a higher chloride content within the concrete than the critical threshold value, the chloride content within the concrete cover and especially at the surface of the steel reinforcement should be determined. Assessment may be made in the field using a variety of rapid test s, which are not included in this standard. For accurate determination of chloride content, concrete samples need to be taken from the structure, prepared for chemical analysis and analysed. For chemical analysis of the concrete with respect to the chloride content either Volhard’s or potentiometric titration are used as the reference s. The chloride content may be expressed as a percentage of chloride by mass of cement or of concrete. The chloride content by mass of cement may be derived using either an assumed value for the cement content of the concrete or a value which has been determined by chemical analysis or from construction records. 标准分享网 w w w .b z f x w .c o m 免费下载 w w w . b z f x w . c o m EN 146292007 E 5 1 Scope This standard describes two s for the determination of the total free and bound acid soluble chloride content of hardened concrete or mortar. This ination is intended for use in estimating the risk of chloride induced corrosion of the steel reinforcement. It may be used on samples of powder obtained either by drilling or from cores or fragments removed from concrete structures or on other appropriate laboratory specimens. 2 Normative references The following referenced documents are indispensable for the application 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. ISO 384, Laboratory glassware - Principles of design and construction of volumetric glassware 3 Materials and apparatus 3.1 Chemicals Deionised water with an electrical conductivity less than 2S/cm; Nitric acid 5 mol/l; Silver nitrate solution 0,02 mol/l; Ammonium thiocyanate NH4SCN solution 0,1 mol/l; Ammonium ferric sulfate indicator solution 100 ml of a cold saturated solution of NH4FeSO42 and 10 ml diluted nitric acid; 3,5,5-trimethylhexanol. NOTE For the potentiometric , additional reagents may be required as specified by the electrode manufacturer to ensure the proper functioning of the electrode. These will be specified in the manufacturer’s instructions for the electrode. 3.2 Apparatus Crushing and grinding equipment as required to prepare samples; 1,18 mm sieve or smaller; ventilated oven, controlled to maintain a temperature of 105 5 C; balance capable of weighing up to 5 g to an accuracy of 1 mg; desiccator; burette, accurate to 0,05 ml; 250 ml glass beaker; magnetic stirrer; w w w . b z f x w . c o m EN 146292007 E 6 heat source; vacuum filtering facility Buchner funnel, filtration flask, medium-textured filter paper; 250 ml volumetric flask; pipettes accurate to 0,1 ml; if required, potentiometric titration facility eg. Ag/AgCl electrode or similar, high resistance mV-meter, burette accurate to 0,05 ml or automatic titration equipment. All volumetric glassware shall be of class A accuracy as defined in ISO 384. 4 Test procedure 4.1 Sampling 4.1.1 Sampling plan Sampling shall be in accordance with a plan prepared for the assessment or repair works by a suitably qualified person. When specifying the locations from which concrete is to be removed, specific care shall be taken of the load bearing capacity and reinforcement of the elements to be sampled. The plan shall take into account the size, , location, orientation, age and structural design of the structure; the results of visual surveys and any other available ination about possible deterioration; the aggregate size and the heterogeneous nature of the concrete; exposure conditions, eg. salt water splash zones. On site checks shall be carried out to ensure that the concrete to be sampled is representative of the elements to be investigated and to confirm the location of reinforcement, which should not be damaged during sampling. The plan shall specify the approximate number, location and depth of samples, including the depth increments. Typically increments do not exceed 25 mm, and it is usual to discard the surface layer. NOTE All holes or damage to the structure from sampling should be repaired or protected immediately to prevent further deterioration. 4.1.2 Collecting powder samples When drilling for powder samples the diameter of the drilling tool and therefore the number of drill holes required to obtain a sufficient sample size is determined by the maximum aggregate size. The powder is collected in separate depth increments, as specified in the sampling plan. A minimum sample size of approximately 1 g is required. NOTE A drill diameter of 20 mm and two holes is normally sufficient to provide 1 g of powder per mm depth of increment. For concrete containing aggregates of maximum size of 20 mm a 20 mm drill should be used. A sample of at least 20 g is normally collected to ensure that it is representative of all of the concrete constituents and not just the aggregate. For larger aggregate sizes a larger drill diameter and sample size should be used. 标准分享网 w w w .b z f x w .c o m 免费下载 w w w . b z f x w . c o m EN 146292007 E 7 4.1.3 Taking core samples A core diameter of 30 mm to 50 mm, depending on the maximum aggregate size, is usually recommended. Larger sizes may be required for large aggregate sizes. Cores shall be marked to indicate their location and orientation with respect to the original concrete surface. For determination of chloride profiles related to the distance from the concrete surface, the cores may be cut into slices as specified in the sampling plan, without using cooling fluid, or may be ground in increments to obtain powder samples. 4.2 Grinding Where the sample requires grinding, it shall be dried in an oven to constant weight at 105 5 C and then allowed to cool to room temperature, for example in a desiccator. When cool it shall be ground to a fine powder to pass a 1,18 mm sieve or smaller, and then homogenised. 4.3 Chemical analysis 4.3.1 General requirements The mass of samples shall be given in grams to the nearest 0,001 g and volumes given in millilitres to the nearest 0,05 ml. Approximately one sample out of every 20 samples or one sample from every batch if less than 20 samples in the batch shall be an interlaboratory standard concrete dust specimen of known chloride content. Occasional duplicate analyses, in which the same sample is analysed twice and the results compared, shall also be carried out to confirm the accuracy of the analysis. NOTE In selecting samples for duplicate analyses note should be taken of the results obtained, in particular of any results which fall outside general trends such as a reduction of chloride concentration with sample depth. 4.3.2 Dissolving chlorides Between 1 g and 5 g of concrete powder shall be weighed and placed in a 250 ml beaker, wetted with 50 ml water, and 10 ml of 5 mol/l nitric acid added, followed by 50 ml hot water. NOTE 1 Adding concentrated acid allows the lab to use a dispenser. This saves time and avoids cross contamination. The addition of hot water quickens boiling and avoids spitting. The mixture shall be heated until boiling and boiled for at least 3 min, stirring continuously. If necessary the mixture shall be filtered immed
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