NEN 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
National Annex NA (informative) Additional guidance for UK users
Bibliography

Provides methods and procedures for the assessment of the in-situ compressive strength of concrete in structures and precast concrete components.