1、raising standards worldwideNO COPYING WITHOUT BSI PERMISSION EXCEPT AS PERMITTED BY COPYRIGHT LAWBSI Standards PublicationBS EN 12504-2:2012Testing concrete in structuresPart 2: Non-destructive testing Determination of rebound numberBS EN 12504-2:2012 BRITISH STANDARDNational forewordThis British St
2、andard is the UK implementation of EN 12504-2:2012. It supersedes BS EN 12504-2:2001 which is withdrawn.The UK participation in its preparation was entrusted to Technical Committee B/517/1, Concrete production and testing.A list of organizations represented on this committee can be obtained on reque
3、st to its secretary.This publication does not purport to include all the necessary provisions of a contract. Users are responsible for its correct application. The British Standards Institution 2012. Published by BSI Standards Limited 2012ISBN 978 0 580 76921 4 ICS 91.100.30 Compliance with a Britis
4、h Standard cannot confer immunity from legal obligations.This British Standard was published under the authority of the Standards Policy and Strategy Committee on 31 January 2013.Amendments issued since publicationDate Text affectedBS EN 12504-2:2012EUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM
5、EN 12504-2 September 2012 ICS 91.100.30 Supersedes EN 12504-2:2001English Version Testing concrete in structures - Part 2: Non-destructive testing -Determination of rebound number Essais pour bton dans les structures - Partie 2: Essais non destructifs - Dtermination de lindice de rebondissement Prfu
6、ng von Beton in Bauwerken - Teil 2: Zerstrungsfreie Prfung - Bestimmung der Rckprallzahl This European Standard was approved by CEN on 13 July 2012. CEN members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the conditions for giving this European Standard the status o
7、f 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
8、). 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,
9、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
10、 Kingdom. EUROPEAN COMMITTEE FOR STANDARDIZATION COMIT EUROPEN DE NORMALISATION EUROPISCHES KOMITEE FR NORMUNG Management Centre: Avenue Marnix 17, B-1000 Brussels 2012 CEN All rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 12504-2:2012:
11、EBS EN 12504-2:2012EN 12504-2:2012 (E) 2 Contents Page Foreword 31 Scope 42 Normative references 43 Principle 44 Apparatus .44.1 Rebound hammer 44.2 Reference anvil 44.3 Abrasive stone .55 Test location .55.1 Selection .55.2 Preparation .56 Procedure .56.1 Preliminary preparation 56.2 Operations 56.
12、3 Reference checking .67 Test result .68 Test report 69 Precision .7Bibliography 8National Annex NA (informative) Guidance on the application of surface hardness testing by rebound hammer 9BS EN 12504-2:2012EN 12504-2:2012 (E) 3 Foreword This document (EN 12504-2:2012) has been prepared by Technical
13、 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 March 2013, and conflicting national standards shall
14、 be withdrawn at the latest by March 2013. 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 EN 12504-2:2001. T
15、his document is based on the International Standard ISO 1920-7, Testing of concrete Part 7: Non-destructive tests on hardened concrete, and reference has been made to ASTM C805, Standard Test Method for Rebound number of hardened concrete. This document has been framed around the use of a Type N, sp
16、ring driven steel hammer, originally designed by Schmidt. This European Standard is one of a series of test methods for concrete. The series EN 12504 “Testing concrete in structures“ consists of the following parts: Part 1: Cored specimens Taking, examining and testing in compression; Part 2: Non-de
17、structive testing Determination of rebound number; Part 3: Determination of pull-out force; Part 4: Determination of ultrasonic pulse velocity. The main changes with respect to the previous edition are listed below: a) editorial revision; b) clarification to the procedure for carrying out the test a
18、nd indicates the required specification of the equipment to be used; c) the option of using an electronic measuring device as well as the mechanical version. According to the CEN/CENELEC Internal Regulations, the national standards organisations of the following countries are bound to implement this
19、 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
20、, Slovenia, Spain, Sweden, Switzerland, Turkey and the United Kingdom. BS EN 12504-2:2012EN 12504-2:2012 (E) 4 1 Scope This European Standard specifies a method for determining the rebound number of an area of hardened concrete using a spring-driven hammer. NOTE 1 The rebound number determined by th
21、is method can be used to assess the uniformity of concrete in situ, to delineate zones or areas of poor quality or deteriorated concrete in structures. NOTE 2 The test method is not intended as an alternative for the compressive strength determination of concrete (EN 12390-3), but with suitable corr
22、elation, it can provide an estimate of in situ compressive strength. For the assessment of in-situ compressive strength see EN 13791. NOTE 3 The hammer may be used for comparative testing, referenced against a concrete with known strength or against a concrete which has been shown that it has come f
23、rom a defined volume of concrete with a population verified as conforming to a particular strength class. 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
24、 cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. EN ISO 6508-1, Metallic materials Rockwell hardness test Part 1: Test method (scales A, B, C, D, E, F, G, H, K, N, T) (ISO 6508-1) 3 Principle A mass propelled by a spring strike
25、s a plunger in contact with the surface of the structure or specimen to be tested. The test result is expressed as a number in terms of the rebound distance of the mass. A number may also be obtained in terms of the energy or velocity differential before and after impact of the mass. 4 Apparatus 4.1
26、 Rebound hammer Consisting of a spring-loaded hammer mass which, when released, strikes a plunger in contact with the surface to be tested. The rebound distance of the hammer mass from the plunger or other rebound values shall be measured. NOTE Several types and sizes of rebound hammers are commerci
27、ally available for testing various strength classes and types of concrete. Each type and size of hammer should be used only with the strength class and type of concrete for which it is intended. 4.2 Reference anvil Steel reference anvil for verification of the hammer, with an impact area having a ha
28、rdness of minimum 52 HRC when tested in accordance with EN ISO 6508-1 and a mass of (16 1) kg and a diameter of approximately 150 mm. Other anvils may be used if it can be demonstrated the accuracy of the readings are not significantly affected. The manufacturers instructions and any other equipment
29、 shall be used to ensure the longitudinal axis of the plunger is perpendicular to the surface of the anvil at impact. NOTE Verification on an anvil will not guarantee that different hammers will yield the same results at other points on the rebound scale. BS EN 12504-2:2012EN 12504-2:2012 (E) 5 4.3
30、Abrasive stone A medium-grain texture silicon carbide stone or equivalent material. 5 Test location 5.1 Selection Concrete elements to be tested shall be at least 100 mm thick and fixed within a structure. Smaller elements or specimens may be tested provided they are rigidly supported. Areas exhibit
31、ing honeycombing, scaling, rough texture, or high porosity should be avoided. In selecting an area to be tested, the following factors should be considered: a) the strength of the concrete; b) type of surface (e.g. formed or unformed); c) type of concrete (e.g. normal or lightweight); d) moisture co
32、ndition of the surface; e) carbonation (if appropriate); f) direction of test; g) other appropriate factors. A test location should be approximately 300 mm 300 mm. 5.2 Preparation Using the abrasive stone, grind heavily textured or soft surfaces, or surfaces with loose mortar, until they are smooth
33、and free of loose material. Smooth-formed or trowelled surfaces may be tested without grinding. Remove any water present on the surface of the concrete. 6 Procedure 6.1 Preliminary preparation 6.1.1 Use the hammer in accordance with the manufacturers instructions for its operation. 6.1.2 Before a se
34、quence of tests on a concrete surface, clean the impact surfaces of the reference anvil and plunger. Perform at least five impacts on the steel reference anvil and record the readings from the next five impacts. If the readings from the last five impacts are not within 3 of the value given by the ma
35、nufacturer, clean and/or adjust the hammer in accordance with the manufacturers instructions and repeat the above. 6.1.3 The hammer shall only be operated at a temperature within the range 0 C to 50 C. 6.2 Operations At the time of the test, the hammer shall meet the requirements defined in 6.1.2. H
36、old the hammer firmly in a position that allows the plunger to impact perpendicularly to the surface being tested. BS EN 12504-2:2012EN 12504-2:2012 (E) 6 Gradually increase the pressure on the plunger until the hammer impacts (see 6.1.1). After impact, record the rebound number based on the rebound
37、 distance and/or energy or velocity measurements. Examine each impression made on the surface after impact and if the impact has crushed or broken through a near-to-surface void, discount the result. Take a minimum of nine valid readings to obtain a reliable estimate of the rebound number for a test
38、 location. Record the position and orientation of the hammer for each set of readings. Ensure that no two impact points are closer than 25 mm and none are within 25 mm of an edge. NOTE It is preferable to draw a regular grid of lines 25 mm to 50 mm apart and take the intersections of the lines as th
39、e test points. 6.3 Reference checking After performing the tests, take five readings using the steel reference anvil. If the readings are not within 3 of the value given by the manufacturer, clean and/or adjust the hammer according to the manufacturers instruction and repeat the test. 7 Test result
40、The rebound number of the test location shall be taken as the median of all the readings, adjusted if necessary to take into account the orientation of the hammer in accordance with the manufacturers instructions. The rebound number shall be expressed as a whole number. If more than 20 % of all the
41、readings differ from the median by more than 30 % the entire set of readings shall be discarded. NOTE If more than one hammer is to be used, a sufficient number of tests should be made on similar concrete surfaces with all hammers, to determine the variation in the results obtained. 8 Test report Th
42、e report shall include: a) identification of the concrete structure/element; b) identification of test location(s); c) identification of the rebound hammer and its specification if known; d) description of preparation of test location(s); e) details of concrete (if known) and its condition; f) date/
43、time of performance of the test; g) rebound number (median of test result readings) adjusted for hammer orientation (if appropriate) for each test location; h) any deviation from the standard test method e.g. presence of water on surface (see 5.2), temperature outside acceptable range (see 6.1.3); B
44、S EN 12504-2:2012EN 12504-2:2012 (E) 7 i) a declaration by the person technically responsible for the test that it was carried out in accordance with this document, except as noted in item h). The report may include: j) individual rebound hammer readings, if required. 9 Precision There are no precis
45、ion data available for this test. BS EN 12504-2:2012EN 12504-2:2012 (E) 8 Bibliography 1 EN 12390-3, Testing hardened concrete Part 3: Compressive strength of test specimens 2 EN 13791, Assessment of in-situ compressive strength in structures and precast concrete components BS EN 12504-2:2012EN 1250
46、4-2:2012 (E) 7 i) a declaration by the person technically responsible for the test that it was carried out in accordance with this document, except as noted in item h). The report may include: j) individual rebound hammer readings, if required. 9 Precision There are no precision data available for t
47、his test. 91 National Annex NA (informative) Guidance on the application of surface hardness testing by rebound hammer NA.1 General The testing of concrete by hardness methods is not generally considered to be a substitute for other well-established methods, but only as a useful preliminary or compl
48、ementary method. Hardness measurements provide information on the quality of the surface layer (about 30 mm deep) of the concrete only. The attention of the user is drawn to the fact that rebound hammers give a measure of the surface hardness of the concrete only, and that the relationship to any ot
49、her property of the concrete is empirical. No single correlation with strength or any other measurable property applies to all concrete, and a calibration for a specific set of circumstances is necessary if acceptable accuracy is to be obtained. It may be possible to apply well established and documented correction factors for a number of influences but it is doubtful whether, if a large number of correction factors were required, the estimate of the property would be sufficiently accurate. It is p
