CEN/TR 17086:2020

SLOVENSKI STANDARD
01-december-2020
Nadaljnja navodila za uporabo EN 13791:2019 in ozadje določil
Further guidance on the application of EN 13791:2019 and background to the provisions
Weiterführende Anleitung zur Anwendung der EN 13791:2019 und Hintergrund zu den
Regelungen
Guide pour l’application de la norme EN 13791:2019 et contexte des spécifications
Ta slovenski standard je istoveten z: CEN/TR 17086:2020
ICS:
91.080.40 Betonske konstrukcije Concrete structures
91.100.30 Beton in betonski izdelki Concrete and concrete
products
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.

CEN/TR 17086
TECHNICAL REPORT
RAPPORT TECHNIQUE
October 2020
TECHNISCHER BERICHT
ICS 91.080.40
English Version
Further guidance on the application of EN 13791:2019 and
background to the provisions
Guide pour l'application de la norme EN 13791:2019 et Weiterführende Anleitung zur Anwendung der EN
contexte des spécifications 13791:2019 und Hintergrund zu den Regelungen

This Technical Report was approved by CEN on 4 October 2020. It has been drawn up by the Technical Committee CEN/TC 104.

CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Turkey and
United Kingdom.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION

EUROPÄISCHES KOMITEE FÜR NORMUNG

CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2020 CEN All rights of exploitation in any form and by any means reserved Ref. No. CEN/TR 17086:2020 E
worldwide for CEN national Members.

Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
2 Symbols and abbreviated terms . 6
3 General principles adopted for the revision . 7
4 In situ compressive strength and other concrete properties assumed in the EN 1992-
1-1 design process . 8
4.1 General . 8
4.2 Concrete compressive strength based on test specimens . 9
4.3 Concrete compressive strength based on the strength of cores from the structure . 11
5 Differences between test specimens and concrete in the structure . 11
5.1 Introduction . 11
5.2 Reference test specimen . 12
5.3 Effects of the moisture condition on in situ specimens . 13
5.4 Effect of maturity on concrete strength . 14
5.5 Effects of curing. 14
5.6 Effects of vibration . 15
5.7 Effects of excess entrapped air . 15
6 Testing variables that influence core strength . 15
6.1 Introduction . 15
6.2 Direction relative to the casting . 15
6.3 Imperfections . 15
6.4 Diameter of core . 16
6.5 Length/diameter ratio . 16
6.6 Flatness of end surfaces . 16
6.7 Capping of end surfaces . 16
6.8 Effect of drilling . 16
6.9 Reinforcement . 16
7 Scope in EN 13791:2019, Clause 1 . 17
8 Terms and definitions, symbols and abbreviations in EN 13791:2019, Clause 3 . 17
9 Investigation objective and test parameters in EN 13791:2019, Clause 4 . 18
10 Test regions and test locations in EN 13791:2019, Clause 5 . 18
11 Core testing and the determination of the in situ compressive strength in
EN 13791:2019, Clause 6 . 18
12 Initial evaluation of the data set in EN 13791:2019, Clause 7 . 19
13 Estimation of compressive strength for structural assessment of an existing
structure in EN 13791:2019, Clause 8 . 20
13.1 Based on core test data only (see EN 13791:2019, 8.1) . 20
13.2 Based on a combination of indirect test data and core test data (see EN 13791:2019,
8.2) . 25
13.3 Use of indirect testing with selected core testing (see EN 13791:2019, 8.3). 30
14 Assessment of compressive strength class of supplied concrete in case of doubt in EN
13791:2019, Clause 9 . 30
14.1 General in EN 13791:2019, 9.1 . 30
14.2 Use of core test data (see EN 13791:2019, 9.2) . 31
14.3 Indirect testing plus selected core testing (see EN 13791:2019, 9.3) . 32
14.4 Screening test using general or specific relationship with an indirect test procedure
(see EN 13791:2019, 9.4) . 32
14.5 Procedure where the producer has declared non-conformity of compressive
strength in EN 13791:2019, 9.5 . 36
14.6 Use of comparative testing . 36
Annex A (informative) Examples of the calculations . 39
A.1 Example A1: Calculating the rebound number . 39
A.2 Example A2: Calculating the in situ strength from core test data . 41
A.2.1 Example A2.1 . 41
A.2.2 Example A2.2 . 41
A.3 Example A3: Assessing the data for a test region to check whether it contains two or
more compressive strength classes . 42
A.4 Example A4: Check for statistical outliers . 45
A.5 Example A5: Calculation of characteristic in situ compressive strength from core test
data . 47
A.6 Example A6: Establishing a correlation between an indirect test and in situ
compressive strength . 48
A.7 Example A7: Using combined indirect testing and core testing to estimate the
characteristic in situ compressive strength and the compressive strength at a
location where only an indirect test result is available . 52
A.8 Example A8: Estimating the characteristic in situ compressive strength using
indirect testing and three cores taken from the weaker area . 55
A.8.1 Example A8.1 . 55
A.8.2 Example A8.2 . 55
A.9 Example A9: Screening test using a generic relationship . 56
A.10 Example A10: Screening test using a rebound hammer that has been calibrated
against test specimens made from the same concrete . 59
A.11 Example A11: Assessment of compressive strength class of concrete as placed using
indirect testing and selected core test data . 63
A.12 Example A12: Assessment of compressive strength class of recently supplied
concrete using core test data only . 64
Bibliography . 66

European foreword
This document (CEN/TR 17086:2020) has been prepared by Technical Committee CEN/TC 104
“Concrete and related products”, the secretariat of which is held by Standards Norway.
Attention is drawn to the possibility that some of the elements of this document may be the subject of
patent rights. CEN shall not be held responsible for identifying any or all such patent rights.
This document should be read in conjunction with EN 13791:2019.

Introduction
(1) To achieve a balanced standard, CEN/TC 104/SC 1/TG 11 comprises experts with different
backgrounds and affiliations. The membership of TG 11 is given in Table 1.
Table 1 — Membership of the European Technical Standard Committee,
CEN/TC 104/SC 1/TG 11, responsible for the revision of EN 13791
Member Affiliation
Professor Tom Harrison Convenor
Dr Chris Clear Secretary
Vesa Anttila Rudus, Finland
Prof. Wolfgang Breit (papers only) Technische Universität Kaiserslautern, Germany
Dr Neil Crook The Concrete Society, UK
Ir. F.B.J. (Jan) Gijsbers CEN/TC250/SC2
Bruno Godart IFSTTAR, France
Dr. Arlindo Gonçalves Laboratório Nacional de Engenharia Civil, Portugal
Christian Herbst JAUSLIN + STEBLER INGENIEURE AG, Switzerland
Rosario Martínez Lebrusant Jefe del Área de Certificación y Hormigones, Spain
Dorthe Mathiesen (papers only) Danish Technological Institute, Denmark
David Revuelta Instituto Eduardo Torroja, Spain
Dr.-Ing. Björn Siebert followed by
Deutscher Beton- und Bautechnik-Verein E.V.
Dr Enrico Schwabach
Swedish Cement and Concrete Research Institute,
Prof. Johan Silfwerbrand
Sweden
Ceyda Sülün followed by Francesco Biasioli ERMCO
José Barros Viegas (papers only) BIBM
Dr.-Ing. Ulrich Wöhnl German expert and member of former TG11
Christos A Zeris (papers only) National Technical University of Athens, Greece

(2) In addition, guidance on rebound hammer and pulse velocity testing
...