EN 13791:2007

Foreword
Introduction
1 Scope
2 Normative references
3 Terms and definitions
4 Symbols and abbreviations
5 Principles
6 Characteristic in-situ compressive strength in relation to
   compressive strength class
7 Assessment of characteristic in-situ compressive strength
   by testing of cores
   7.1 Specimens
   7.2 Number of test specimens
   7.3 Assessment
       7.3.1 General
       7.3.2 Approach A
       7.3.3 Approach B
8 Assessment of characteristic in-situ compressive strength
   by indirect methods
   8.1 General
       8.1.1 Methods
       8.1.2 Alternative 1 - Direct correlation with cores
       8.1.3 Alternative 2 - Calibration with cores for a
             limited strength range using an established
             relationship
   8.2 Indirect tests correlated with in-situ compressive
       strength, (Alternative 1)
       8.2.1 Application
       8.2.2 Testing procedure
       8.2.3 Establishing the relationship between test result
             and in-situ compressive strength
       8.2.4 Assessment of in-situ compressive strength
   8.3 Use of a relationship determined from a limited number
       of cores and a basic curve, (Alternative 2)
       8.3.1 General
       8.3.2 Testing
       8.3.3 Procedure
       8.3.4 Validity of relationships
       8.3.5 Estimation of in-situ compressive strength
   8.4 Combination of in-situ strength test results by various
       test methods
9 Assessment where conformity of concrete based on standard
   tests is in doubt:
10 Assessment report
Annex A (informative) Factors influencing core strength
      A.1 General
      A.2 Concrete characteristics
          A.2.1 Moisture content
          A.2.2 Voidage
          A.2.3 Direction relative to the casting
          A.2.4 Imperfections
      A.3 Testing variables
          A.3.1 Diameter of core
          A.3.2 Length/diameter ratio
          A.3.3 Flatness of end surfaces
          A.3.4 Capping of end surfaces
          A.3.5 Effect of drilling
          A.3.6 Reinforcement
Annex B (informative) Factors influencing results by indirect
        test methods
      B.1 Rebound hammer tests
      B.2 Ultrasonic pulse velocity measurements
      B.3 Pull-out tests
Annex C (informative) Concepts concerning the relationship
        between in-situ strength and strength from standard
        test specimens
Annex D (informative) Guidelines for planning, sampling and
        evaluation of test results when assessing in-situ
        strength
      D.1 Planning
      D.2 Sampling
      D.3 Testing programme
      D.4 Assessment
Bibliography

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.NOTEIn 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.