BS EN 13791-2007 Assessment of in-situ compressive strength in structures and precast concrete components.pdf

BRITISH STANDARD BS EN 13791:2007 Assessment of in-situ compressive strength in structures and precast concrete components The European Standard EN 13791:2007 has the status of a British Standard ICS 91.080.40 ? BS EN 13791:2007 This British Standard was published under the authority of the Standards Policy and Strategy Committee on 28 February 2007 © BSI 2007 ISBN 978 0 580 50271 2 National foreword This British Standard was published by BSI. It is the UK implementation of EN 13791:2007. It partially supersedes BS 6089:1981 which will be withdrawn on publication of complementary guidance (currently in preparation). The UK participation in its preparation was entrusted by Technical Committee B/517, Concrete, to Subcommittee B/517/1, Concrete production and testing. A list of organizations represented on B/517/1 can be obtained on request to its secretary. A National Annex NA (informative) is included, which provides additional guidance for use in the UK. 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 EUROPEAN STANDARD NORME EUROPÉENNE EUROPÄISCHE NORM EN 13791 January 2007 ICS 91.080.40 English Version Assessment of in-situ compressive strength in structures and precast concrete components Evaluation de la résistance à la compression du béton en place dans les structures et les éléments préfabriqués Bewertung der Druckfestigkeit von Beton in Bauwerken oder in Bauwerksteilen This European Standard was approved by CEN on 10 November 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 COMITÉ EUROPÉEN DE NORMALISATION EUROPÄISCHES KOMITEE FÜR NORMUNG Management Centre: rue de Stassart, 36 B-1050 Brussels © 2007 CENAll rights of exploitation in any form and by any means reserved worldwide for CEN national Members. Ref. No. EN 13791:2007: E EN 13791:2007 (E) 2 Contents Page Foreword4 Introduction.5 1 Scope 7 2 Normative references7 3 Terms and definitions .8 4 Symbols and abbreviations9 5 Principles10 6 Characteristic in-situ compressive strength in relation to compressive strength class.10 7 Assessment of characteristic in-situ compressive strength by testing of cores.11 7.1 Specimens11 7.2 Number of test specimens11 7.3 Assessment11 7.3.1 General11 7.3.2 Approach A.12 7.3.3 Approach B.12 8 Assessment of characteristic in-situ compressive strength by indirect methods.13 8.1 General13 8.1.1 Methods13 8.1.2 Alternative 1 Direct correlation with cores 13 8.1.3 Alternative 2 Calibration with cores for a limited strength range using an established relationship.14 8.2 Indirect tests correlated with in-situ compressive strength, (Alternative 1).14 8.2.1 Application .14 8.2.2 Testing procedure14 8.2.3 Establishing the relationship between test result and in-situ compressive strength14 8.2.4 Assessment of in-situ compressive strength.14 8.3 Use of a relationship determined from a limited number of cores and a basic curve, (Alter- native 2) 15 8.3.1 General15 8.3.2 Testing15 8.3.3 Procedure .15 8.3.4 Validity of relationships 19 8.3.5 Estimation of in-situ compressive strength19 8.4 Combination of in-situ strength test results by various test methods19 9 Assessment where conformity of concrete based on standard tests is in doubt:.20 10 Assessment report 21 Annex A (informative) Factors influencing core strength22 A.1 General22 A.2 Concrete characteristics.22 A.2.1 Moisture content22 A.2.2 Voidage.22 A.2.3 Direction relative to the casting.22 A.2.4 Imperfections .22 A.3 Testing variables22 A.3.1 Diameter of core.22 A.3.2 Length/diameter ratio23 ? EN 13791:2007 (E) 3 A.3.3 Flatness of end surfaces 23 A.3.4 Capping of end surfaces.23 A.3.5 Effect of drilling .23 A.3.6 Reinforcement .23 Annex B (informative) Factors influencing results by indirect test methods24 B.1 Rebound hammer tests.24 B.2 Ultrasonic pulse velocity measurements24 B.3 Pull-out tests24 Annex C (informative) Concepts concerning the relationship between in-situ strength and strength from standard test specimens25 Annex D(informative)Guidelines for planning, sampling and evaluation of test results when assessing in-situ strength26 D.1 Planning26 D.2 Sampling.26 D.3 Testing programme.26 D.4 Assessment .27 Bibliography28 National Annex NA (informative) Additional guidance for UK users.29 ? EN 13791:2007 (E) 4 Foreword This document (EN 13791:2007) 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 July 2007, and conflicting national standards shall be withdrawn at the latest by July 2007. 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 United Kingdom. ? EN 13791:2007 (E) 5 Introduction This European Standard provides techniques for estimating in-situ compressive strength in concrete structures and precast concrete components. Testing in-situ strength takes into account the effects of both the materials and execution (compaction, curing, etc.). These tests do not replace concrete testing according to EN 206-1. EN 206-1 refers to the guidance of this standard for assessing the strength in structures and precast concrete components. The following examples illustrate where this estimate of in-situ strength of concrete may be required: when an existing structure is to be modified or redesigned; to assess structural adequacy when doubt arises about the compressive strength in the structure due to defective workmanship, deterioration of concrete due to fire or other causes; when an assessment of the in-situ concrete strength is needed during construction; to assess structural adequacy in the case of non-conformity of the compressive strength obtained from standard test specimens; assessment of conformity of the in-situ concrete compressive strength when specified in a specification or product standard. Where identified in this standard, national provisions are permitted or required. An outline of the procedures for these different uses of this standard is given in Flowchart 1. For specific production conditions and constituent materials, development of economic design where permitted by national provisions may be possible through the assessing the partial safety factor, c from knowledge of the in-situ compressive strength and the strength of standard test specimens. When assessing compressive strengths in cases other than checking the quality of the concrete or the workmanship during execution or before accepting the structure for use, the appropriate reduction in the partial safety factor should be determined on a case-by-case basis according to national provisions. ? EN 13791:2007 (E) 6 Flowchart 1 ? EN 13791:2007 (E) 7 1 Scope This European Standard: gives methods and procedures for the assessment of the in-situ compressive strength of concrete in structures and precast concrete components; provides principles and guidance for establishing the relationships between test results from indirect test methods and the in-situ core strength; provides guidance for the assessment of the in-situ concrete compressive strength in structures or precast concrete components by indirect or combined methods. This European Standard does not include the following cases: where indirect methods are used without correlation to core strength; assessment based on cores less than 50 mm in diameter; assessment based on less than 3 cores; use of microcores. NOTE In these cases provisions valid in place of use apply. This European Standard is not for the assessment of conformity of concrete compressive strength in accordance with EN 206-1 or EN 13369 except as indicated in EN 206-1:2000, 5.5.1.2 or 8.4. 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. EN 206-1:2000, Concrete Part 1: Specification, performance, production and conformity EN 12350-1,Testing fresh concrete Part 1: Sampling EN 12390-1, Testing hardened concrete - Part 1: Shape, dimensions and other requirements for specimens and moulds EN 12390-2, Testing hardened concrete Part 2: Making and curing specimens for strength tests EN 12390-3, Testing hardened concrete Part 3: Compressive strength of test specimens EN 12504-1, Testing concrete in structures Part 1: Cored specimens Taking, examining and testing in compression EN 12504-2, Testing concrete in structures Part 2: Non-destructive testing Determination of rebound number EN 12504-3, Testing concrete in structures Part 3: Determination of pull-out force ? EN 13791:2007 (E) 8 EN 12504-4, Testing concrete in structures Part 4: Determination of ultrasonic pulse velocity 3 Terms and definitions For the purposes of this European Standard, the terms and definitions given in EN 206-1:2000 and the following apply. 3.1 standard compressive strength compressive strength determined on standard test specimens (cubes or cylinders) which are sampled, made, cured and tested in accordance with EN 12350-1, EN 12390-2 and EN 12390-3 3.2 core compressive strength compressive strength of a core determined in accordance with EN 12504-1 3.3 in-situ compressive strength strength in a structural element or precast concrete components expressed in terms of the equivalent strength of a standard cube or cylinder specimen 3.4 characteristic in-situ compressive strength value of in-situ compressive strength below which 5 % of the population of all possible strength determinations of the volume of concrete under consideration are expected to fall NOTE This population is unlikely to be the same population used to determine the conformity of the fresh concrete in EN 206-1. 3.5 test location limited area selected for measurements used to estimate one test result, which is to be used in the estimation of in-situ compressive strength 3.6 test region one or several structural elements, or precast concrete components assumed or known to be from the same population. A test region contains several test locations ? EN 13791:2007 (E) 9 4 Symbols and abbreviations ?fshift of the basic curve ?fdifference between the core strength and the strength value according to the basic relationship ?fm(n)mean of n, values of ?f Fpull-out force test result fisin-situ compressive strength test result fis, lowestlowest in-situ compressive strength test result fm(n), ismean in-situ compressive strength of n test results fckcharacteristic compressive strength of standard specimens fck, ischaracteristic in-situ compressive strength fck, is, cubecharacteristic in-situ compressive strength expressed in equivalent strength of a 150 mm cube, see 7.1 fck, is, cylcharacteristic in-situ compressive strength expressed in equivalent strength of a 150 mm × 300 mm cylinder, see 7.1 fis, lestimated in-situ compressive strength test result by indirect test methods when a specific relationship is established by core tests, (Alternative 1) fis, Festimated in-situ compressive strength test result by pull-out tests calibrated by core tests, (Alternative 2) fis, Restimated in-situ compressive strength test result by rebound hammer tests calibrated by core tests, (Alternative 2) fis, vestimated in-situ compressive strength test result by ultrasonic pulse velocity tests calibrated by core tests, (Alternative 2) fFinitial value of in-situ strength obtained from the basic curve for a pull-out force, Figure 4, test result F used in the determination of the shift fRinitial value of in-situ strength obtained from the basic curve for a rebound hammer, Figure 2, test result R used in the determination of the shift fvinitial value of in-situ strength obtained from the basic curve for a pulse-velocity, Figure 3 test result v used in the determination of the shift cpartial safety factor for concrete kmargin associated with small numbers of test results k1coefficient that depends on the number of paired tests k2coefficient that depends upon provisions valid in the place of use or, if none are given, a coefficient with a value of 1,48 nnumber of test results Rrebound hammer test result sstandard deviation vultrasonic pulse velocity test result ? EN 13791:2007 (E) 10 5 Principles Assessment of in-situ compressive strength directly from core tests constitutes the reference method, see 7. The assessment of in-situ compressive strength may also be done indirectly by other tests, see 8.2 and 8.3, or by a combination of various test methods, see 8.4. Where indirect tests are used, the uncertainty associated with the relationship between the test and core test is taken into account. The test data may be used to estimate the in-situ characteristic strength and the corresponding strength class according to EN 206-1. 6 Characteristic in-situ compressive strength in relation to compressive strength class Table 1 gives requirements for the minimum characteristic in-situ compressive strength with respect to the compressive strength classes according to EN 206-1. Table 1 Minimum characteristic in-situ compressive strength for the EN 206-1 compressiv