1、December 2015 English price group 4No part of this translation 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 91.100.30!%Izs“2388780www.din.de
2、DIN EN 12390-2/A20Testing hardened concrete Part 2: Making and curing specimens for strength tests; Amendment A20,English translation of DIN EN 12390-2/A20:2015-12Prfung von Festbeton Teil 2: Herstellung und Lagerung von Probekrpern fr Festigkeitsprfungen,Englische bersetzung von DIN EN 12390-2/A20:
3、2015-12Essai pour bton durci Partie 2: Confection et conservation des prouvettes pour essais de rsistance,Traduction anglaise de DIN EN 12390-2/A20:2015-12ModifiesDIN EN 12390-2:2009-08 andDIN EN 12390-2Corrigendum 1:2012-02www.beuth.deDocument comprises 3 pagesDTranslation by DIN-Sprachendienst.In
4、case of doubt, the German-language original shall be considered authoritative.11.15 DIN EN 12390-2/A20:2015-12 2 A comma is used as the decimal marker. Foreword This document has been prepared by DIN-Normenausschuss Bauwesen (DIN Standards Committee Building and Civil Engineering), Working Committee
5、 NA 005-07-05 AA Prfverfahren fr Beton (SpA CEN/TC 104/SC 1/TG 8 und CEN/TC 104/SC 1/TG 11 sowie CEN/TC 51/WG 12). It includes amendments to the National Annex NA (informative) “Curing conditions for test specimens for compressive strength testing and determining the elastic modulus” of DIN EN 12390
6、-2:2009-08 and DIN EN 12390-2 Corrigendum 1:2012-02. This Amendment is based on the experience that the curing of test specimens in a climate chamber irrespective of their age at the time of testing, i.e. the removal of the specimens from the water bath after 7 days, is not realistic for concrete sp
7、ecimens that have reached an age of more than 28 days after they have been made. Research findings show that irrespective of curing duration and concrete type there are no significant differences in compressive strengths between a curing A (7 days in water, then in standard atmosphere at a temperatu
8、re of 20 C and a relative humidity of 65 %) and a curing B (in water up to 21 days before testing, then in standard atmosphere at 20 C and a relative humidity of 65 %). Furthermore, it confirmed that the conversion factors for fc,dryto fc,cubeaccording to DIN 1045-2 (0,92 and 0,95) are also applicab
9、le when the specimens are tested at a higher age. The amendments refer to: a) arrangement for the curing of test specimens for a period exceeding 28 days. The National Annex shall read as follows: DIN EN 12390-2/A20:2015-12 3 National Annex NA (informative) Curing conditions for test specimens for c
10、ompressive strength testing and determining the elastic modulus NA.1 General This European Standard specifies methods for making and curing test specimens for strength tests. Alternative curing conditions are permitted according to 5.5.3 of this European Standard. Such deviating conditions are commo
11、nly used in Germany and are expressly required in the relevant material standards on concrete. Therefore, the curing conditions commonly used in Germany for strength testing and for determining the elastic modulus are described in this National Annex. This Annex describes the curing conditions for c
12、oncrete test specimens in accordance with DIN EN 12390-2:2009-08, 5.5.3, with which the compressive strength fc,dryor the elastic modulus Ec,dryare determined. NA.2 Curing conditions After they are made, leave the test specimens in the moulds for (24 2) hours in a closed room with an air temperature
13、 of 15 C to 22 C (the aim should be to achieve a temperature range of (20 2) C), protected against draughts and dehydration, e.g. by covering them with PE film. During the setting time the specimens are to be protected against shock and vibration, e.g. during transport. After (24 2) hours remove the
14、 specimens from the moulds and cure them for at least 6 days on a grating in a bath of tap water at a temperature of (20 2) C or on a slatted frame in a humidity chamber at a temperature of (20 2) C and 95 % relative humidity. Take the specimens out of the water bath or humidity chamber at least 21
15、days prior to testing and cure them on a slatted frame in a closed room with an air temperature of 15 C to 22 C (the aim should be to achieve a temperature range of (20 2) C) and a relative humidity of (65 5) %). Specimens are to be protected from direct draughts. For testing the specimens at an age of 28 days, they shall, as a consequence, be cured for 6 days in a water bath or a humidity chamber after they have been removed from the moulds, and then in a closed room under the above mentioned conditions.
