1、May 2008DEUTSCHE NORM English price group 18No part of this standard may be reproduced without prior permission ofDIN Deutsches Institut fr Normung e. V., Berlin. Beuth Verlag GmbH, 10772 Berlin, Germany,has the exclusive right of sale for German Standards (DIN-Normen).ICS 91.080.40!$Ny“1438656www.d
2、in.deDDIN EN 13791Assessment of in-situ compressive strength in structures and precastconcrete componentsEnglish version of DIN EN 13791:2008-05Bewertung der Druckfestigkeit von Beton in Bauwerken oder in BauwerksteilenEnglische Fassung DIN EN 13791:2008-05www.beuth.deDocument comprises 36 pagesDIN
3、EN 13791:2008-05 2 National foreword This standard has been prepared by Technical Committee CEN/TC 104 “Concrete and related products” (Secretariat: DIN, Germany). It contains the English-language version of EN 13791:2007 and a national annex specifying a number of provisions which in accordance wit
4、h the European Standard are applicable at national level; these national provisions are referenced in the body of the standard in the form of national remarks. The responsible German body involved in its preparation was the Normenausschuss Bauwesen (Building and Civil Engineering Standards Committee
5、), Technical Committee NA 005-07-05 AA Prfverfahren fr Beton, which was also responsible for drawing up the national annex. A draft version of the national annex was published as E DIN 18999-15:2005-06; comments on E DIN 18999-15:2005-06 have been incorporated into the national annex of the present
6、document. National Annex NA (informative) National Provisions NA.1 Introduction This national annex gives rules for assessing the in-situ compressive strength of concrete in structures and precast concrete components which according to EN 13791 are to be laid down as national provisions, and additio
7、nal provisions for applications that are not expressly included in the scope of the European Standard (see Clause 1 of EN 13791). References to these national provisions are made in the European Standard in the form of national remarks indicated by “(N.)”. NA.2 Scope This national annex describes th
8、e application and assessment of the in-situ compressive strength of concrete in structures based on results of non-destructive and destructive testing for the following cases: where indirect methods are used without correlation to core strength (see NA.4.5); where basic curves for established relati
9、onships other than those covered in Clause 8 of EN 13791 are to be used (see NA.4.6); where assessment is based on fewer than three cores (see NA.4.4). The method described in this standard is not applicable for assessing conformity in accordance with DIN EN 206-1:2001-07/DIN 1045-2:2001-07, 8.2.1 o
10、r for determining the concretes “identity” as described in DIN 1045-3:2001-07, A.2. Where sufficient compressive strength cannot be demonstrated using the above-mentioned methods, the in-situ compressive strength may be assessed on the basis of the present standard for the purposes of loadbearing ca
11、pacity verification. An outline of the procedures for applying this standard in Germany is given in the flowchart shown in Figure NA.1. DIN EN 13791:2008-05 3 NA.3 Symbols and abbreviations fc,is,core50 in-situ compressive strength test result for air-dried cores having a diameter of 50 mm cal fccom
12、pressive strength assigned to the Rmvalue by the reference line, related to a 150 mm cube; Rmmedian of 9 rebound heights measured on one cube; fcm, Rmmmean compressive strength value and the median rebound height, respectively, for all cubes; sf, sRstandard deviations for compressive strength values
13、 and rebound heights, respectively; rfRcorrelation coefficient for n samples Figure NA.1 DIN EN 13791:2008-05 4 NA.4 Application of test methods NA.4.1 Minimum characteristic in-situ compressive strength of light-weight concrete with a closed structure Table NA.1 Minimum characteristic in-situ compr
14、essive strength of light-weight concrete with a closed structure, for compressive strength classes according to DIN EN 206-1 Minimum characteristic in-situ compressive strength of light-weight concrete with a closed structure N/mm2Compressive strength class according to DIN EN 206-1 Ratio of in-situ
15、 characteristic strength to characteristic strength of standard specimens fck,is,cylfck,is,cubeLC8/9 0,85 7 8 LC12/13 0,85 10 11 LC16/18 0,85 14 15 LC20/22 0,85 17 19 LC25/28 0,85 21 24 LC30/33 0,85 26 28 LC35/38 0,85 30 32 LC40/44 0,85 34 37 LC45/50 0,85 38 43 LC50/55 0,85 43 47 LC55/60 0,85 47 47
16、LC60/66 0,85 51 56 LC70/77 0,85 60 65 LC80/88 0,85 68 75 NOTE 1 The in-situ compressive strength may be lower than that measured on standard test specimens taken from the same batch of concrete. NOTE 2 The ratio 0,85 is part of cas in EN 1992-1-1:2004. NA.4.2 Provisions on the testing and assessment
17、 of cores Subclause 7.1 shall be amended with the following: Cores should have a diameter of 100 mm or 150 mm, but no smaller than 50 mm, in special cases. The specimen height, including any caps, should or shall be equal to the specimen diameter; a tolerance of 10 % is permitted in individual cases
18、. Testing shall be carried out on air-dried cores. When taking specimens from largely dry components with subsequent wet cutting or wet grinding, cores are to be conditioned for at least 12 hours in standard laboratory atmosphere prior to testing. Other specimen sizes and conditioning parameters are
19、 subject to agreement and shall be documented. DIN EN 13791:2008-05 5 The compressive strength of an air-dried core having a nominal diameter of 100 mm or 150 mm may be deemed equivalent to that of a saturated 150 mm cube. For cores with a nominal diameter of 50 mm the following applies: fc,is,cube=
20、 0,9 fc,is,core50NA.4.3 Number of specimens An expert who has experience assessing in-situ concrete shall be called upon to determine the type and scope of testing and to evaluate test results. The minimum number of cores to be taken from a structure shall be as in DIN 1045-3:2001-07, A.2. In the ca
21、se of destructive testing, at least the following number of cores are needed: a) For cores with a diameter 100 mm, the same number of specimens as specified in DIN 1045-3:2001-07, A.2 shall be used. b) For cores with a diameter 16 mm, twice the number of specimens as specified in DIN 1045-3:2001-07,
22、 A.2 shall be used. For non-destructive testing, at least three times the number of specimens specified in DIN 1045-3:2001-07, A.2 shall be used. NA.4.4 Destructive testing of two cores Two cores, with or without combination with an indirect test method, may be used for assessing results as in Claus
23、e 9 if it is ensured that the concrete being assessed comes from a limited number of batches taken from a small region. NA.4.5 Rebound hammer testing without correlation to core strength Rebound hammer testing is carried out to determine a characteristic value for the elastic behaviour of the concre
24、te near the surface; this can in turn be used, under certain conditions, to determine compressive strength. Testing shall be carried out in accordance with DIN EN 12504-2. Rebound hammer testing to determine compressive strength shall not be performed on concrete surfaces which have been exposed to
25、external influences such as fire, frost or chemical attack. In older structures, the carbonization depth shall be measured prior to rebound hammer testing. If this depth is greater than 5 mm, Table NA.1 cannot be used. For the purposes of verifying loadbearing capacity in-situ concrete may be assign
26、ed to a compressive strength class as in DIN EN 206-1/DIN 1045-2 if the rebound hammer test results correspond to the values specified in Table NA.2. DIN EN 13791:2008-05 6 Table NA.2 Rebound numbers and relevant compressive strength class as in DIN EN 206-1/DIN 1045-2 Min. median for each specimen
27、Min. median for each test area Compressive strength class Reading Reading C8/10 26 30 C12/15 30 33 C16/20 32 35 C20/25 35 38 C25/30 37 40 C30/37 40 43 C35/45 44 47 C40/50 46 49 C45/55 48 51 C50/60 50 53 This test method is not suitable for lightweight concrete or high strength concrete. NA.4.6 Refer
28、ence line W In addition to the specifications of DIN EN 13791, 8.4, a reference line W (for testing on cubes) may be used for assessment purposes. 150 mm cubes made and cured as specified in DIN EN 12390-2:2001-06, Annex NA (fc,dry) shall be used to produce the reference line. Before starting the im
29、pact test, place the cube in the compression testing machine and subject it to a load of about 2,5 N/mm2. Hit each of two opposing surfaces 4 to 5 times, with no two impact points being closer than 25 mm (i.e. the centre-to-centre distance is at least 25 mm) and with all points being at least 30 mm
30、from an edge. Determine the median of 9 measured rebound heights, Rm. Then, determine the compressive strength of the cube, fc, in accordance with DIN EN 12390-3. For each reference line, determine at least 10 pairs of associated fcand Rmvalues. The compressive strengths of the cubes should be distr
31、ibuted as evenly as possible over the entire range investigated. The maximum and minimum values for fcshould differ by at least 20 N/mm2and normally by no more than 30 N/mm2. To achieve this, a) the water content may be varied while otherwise retaining the same concrete composition and age, or b) th
32、e testing age of the cubes may be varied while retaining the same concrete composition. The reference line plotted in a coordinate system (see Figure NA.2) with fcas the ordinate (y-coordinate) and Rmas the abscissa (x-coordinate) shall be calculated using the following equation: DIN EN 13791:2008-0
33、5 7 cal fc= fcm+ rfRsf /sR(Rm Rmm) where cal fcis the compressive strength assigned to the Rmvalue by the reference line, related to a 150 mm cube; Rmis the median of 9 rebound heights measured on one cube; fcm, Rmmare the mean compressive strength value and the median rebound height, respectively,
34、for all cubes; sf, sRare the standard deviations for compressive strength values and rebound heights, respectively; rfRis the correlation coefficient for n samples, with ()()fR1cmcmmmfR.11ssffRRnrn= 1 Reference line W Figure NA.2 Example of a reference line W The calculated reference line may only b
35、e used if the correlation coefficient rfRis equal to or greater than the correlation coefficient r given in Table NA.3 for the relevant sampling size n. Intermediate values may be linearly interpolated. DIN EN 13791:2008-05 8 Table NA.3 Minimum correlation coefficient required Number of samples n Co
36、rrelation coefficient r 10 0,89 12 0,87 14 0,86 16 0,85 18 0,84 20 0,83 25 0,82 30 0,81 35 0,80 The characteristic in-situ compressive strength shall be calculated as described in EN 13791:2007, 8.2.4. NA.4.7 Partial safety factors Partial safety factors shall not be modified. EUROPEAN STANDARDNORME
37、 EUROPENNEEUROPISCHE NORMEN 13791January 2007ICS 91.080.40English VersionAssessment of in-situ compressive strength in structures andprecast concrete componentsEvaluation de la rsistance la compression du bton enplace dans les structures et les lments prfabriqusBewertung der Druckfestigkeit von Beto
38、n in Bauwerkenoder in BauwerksteilenThis 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 EuropeanStandard the status of a national standard without any alteration. Up-to
39、-date lists and bibliographical references concerning such nationalstandards 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 translationunder t
40、he responsibility of a CEN member into its own language and notified to the CEN Management Centre has the same status as theofficial versions.CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Cyprus, Czech Republic, Denmark, Estonia, Finland,France, Germany, Greece, Hungar
41、y, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway, Poland, Portugal,Romania, Slovakia, Slovenia, Spain, Sweden, Switzerland and United Kingdom.EUROPEAN COMMITTEE FOR STANDARDIZATIONCOMIT EUROPEN DE NORMALISATIONEUROPISCHES KOMITEE FR NORMUNGManagement Centre: rue
42、de Stassart, 36 B-1050 Brussels 2007 CEN All rights of exploitation in any form and by any means reservedworldwide for CEN national Members.Ref. No. EN 13791:2007: E2 Contents Page Foreword4 Introduction .5 1 Scope 7 2 Normative references 7 3 Terms and definitions .8 4 Symbols and abbreviations 9 5
43、 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 Specimens 11 7.2 Number of test specimens11 7.3.2 Approach A.12 7.3.3 Approach B.12 8 Assessment of charac
44、teristic in-situ compressive strength by indirect methods.13 8.1 General13 8.1.1 Methods 13 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 com
45、pressive 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 an
46、d a basic curve, (Alter-native 2) 15 8.3.1 General15 8.3.2 Testing 15 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 methods 19 9 Assessment where conformity of concrete based
47、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
48、.1 Diameter of core.22 A.3.2 Length/diameter ratio 23 DIN EN 13791:2008-05 EN 13791:2007 (E) 7.3.1 General12 7.3 Assessment12 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 infl
49、uencing 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 assessing in-situ strength26 D.1 Planning26 D.2 Sampling.26 D.3 Testing programme .26 D.4 Assessment .27 Bibliography28 Annex D (informative) Guidelines for planning, sampling and evaluation of test results when DIN EN 13791:2008-05 4 Foreword This document (EN 13791:2007)
