Link points to Internet Archive / others. Not hosted by InfraLens. Details
IS 13311:1992 Part 1 is the Indian Standard (BIS) for non-destructive testing of concrete - ultrasonic pulse velocity test. This standard (Part 1) covers the procedure for the Ultrasonic Pulse Velocity (UPV) test, a non-destructive method to assess the relative quality, uniformity, and presence of cracks or voids in hardened concrete. It provides criteria for classifying concrete quality based on the measured velocity of an ultrasonic pulse through the material.
Describes the procedure for assessing the quality of concrete using the ultrasonic pulse velocity method.
Overview
Status
Current
Usage level
Frequently Used
Domain
Materials Science — Tunneling and Underground Structures
BIM-relevant code. See the BIM Hub for ISO 19650, IFC, and LOD/LOIN frameworks used alongside it.
Practical Notes
! Surface preparation is critical; ensure a smooth surface and use an appropriate couplant (like grease) for good acoustic contact between the transducer and concrete.
! Results are significantly influenced by the presence of reinforcement, moisture content, and aggregate type. The direct transmission method (transducers on opposite faces) is the most reliable.
! The standard provides a general quality grading; establishing a specific correlation between pulse velocity and compressive strength requires extensive laboratory calibration for each specific concrete mix.
Standard Test Method for Rebound Number of Hardened Concrete
Defines the procedure for determining the rebound number of hardened concrete using a spring-driven steel hammer.
EN 12504-2:2021CEN (European Committee for Standardization), Europe
HighCurrent
Testing concrete in structures - Part 2: Non-destructive testing - Determination of rebound number
Specifies the method for determining the rebound number of an area of hardened concrete using a rebound hammer.
ISO 1920-7:2004ISO (International Organization for Standardization), International
MediumCurrent
Testing of concrete — Part 7: Non-destructive tests on hardened concrete
Covers several NDT methods, including rebound hammer, determination of ultrasonic pulse velocity, and reinforcement location.
BS 1881-202:1986BSI (British Standards Institution), UK
HighWithdrawn
Testing concrete. Recommendations for surface hardness testing by rebound hammer
Provided recommendations for using the rebound hammer to assess concrete surface hardness and uniformity.
Key Differences
≠IS 13311 requires taking 'about 6 readings' per test location, whereas EN 12504-2 mandates a minimum of 9 valid readings and ASTM C805 specifies 10 readings.
≠The data rejection criteria differ significantly. IS 13311 suggests discarding readings that deviate by more than 15% from the average. ASTM C805 requires discarding readings that differ by more than 6 units from the average.
≠While all standards recommend establishing a specific correlation between rebound number and strength, IS 13311 (1992) provides graphical correlations in its annex which are sometimes used directly. Modern standards like EN 12504-2 are much stricter, prohibiting the use of such generic curves for strength estimation and mandating specific correlation establishment.
≠The minimum specified distance between impact points is 20 mm in IS 13311, which is less than the 25 mm (1 inch) required by both EN 12504-2 and ASTM C805.
Key Similarities
≈All standards are based on the same fundamental principle: measuring the rebound of a spring-loaded mass after it impacts a concrete surface to obtain a surface hardness index.
≈The standard impact energy for the most common (Type N) rebound hammer is specified as 2.207 Nm across IS 13311, EN 12504-2, and ASTM C805.
≈All standards universally require the test surface to be smooth, clean, dry, and free of carbonation, recommending the use of a grinding stone for preparation.
≈There is a common consensus across all standards that test results are influenced by factors such as moisture, carbonation, age, concrete composition, and surface texture, which must be considered during interpretation.
≈All standards specify a minimum structural member thickness of 100 mm for valid testing to avoid deflection and ensure the impact energy is absorbed by the concrete mass.
Parameter Comparison
Parameter
IS Value
International
Source
Standard Impact Energy (Type N)
2.207 Nm
2.207 Nm (Nominal)
EN 12504-2 / ASTM C805
Readings per Test Area
About 6
10 readings
ASTM C805
Readings per Test Area
About 6
Minimum of 9
EN 12504-2
Minimum Distance Between Impacts
20 mm
25 mm (1 in.)
EN 12504-2 / ASTM C805
Minimum Member Thickness
100 mm
100 mm (4 in.)
EN 12504-2 / ASTM C805
Data Rejection Rule
Discard if reading deviates > 15% from the average
Discard if reading deviates > 6 units from the average
ASTM C805
Minimum Age for Testing (Guideline)
Not reliable before 14 days (unless calibrated)
No specific minimum age, but correlation is age-dependent
EN 12504-2 / ASTM C805
⚠ Verify details from original standards before use
Key Values6
Quick Reference Values
Pulse velocity for 'Excellent' quality concreteAbove 4.5 km/s
Pulse velocity for 'Good' quality concrete3.5 to 4.5 km/s
Pulse velocity for 'Medium' quality concrete3.0 to 3.5 km/s
Pulse velocity for 'Doubtful' quality concreteBelow 3.0 km/s
Recommended transducer frequency (path > 500mm)20 to 60 kHz
Recommended transducer frequency (path < 500mm)50 to 150 kHz
Key Formulas
V = L / T — Pulse velocity (V) as a function of path length (L) and transit time (T)
Tables & Referenced Sections
Key Tables
Table 1 - Velocity Criterion for Concrete Quality Grading
Key Clauses
Clause 5 - Apparatus
Clause 6 - Procedure
Clause 7 - Interpretation of Results
Annex A - Factors Influencing Pulse Velocity Measurements
Frequently Asked Questions4
What does a pulse velocity above 4.5 km/s indicate?+
It indicates 'Excellent' quality concrete, suggesting good compaction and uniformity (Table 1).
Can this test determine the compressive strength of concrete?+
Not directly. It is primarily used to assess uniformity and quality. While a correlation to strength can be developed for a specific mix, it is not a direct measurement of strength (Clause 7.1.1).
What is the purpose of the couplant?+
A couplant (e.g., grease, petroleum jelly) is used to ensure proper acoustic coupling by eliminating air gaps between the transducer and the concrete surface, allowing the ultrasonic pulse to travel efficiently (Clause 6.2).
Which transmission method is most reliable?+
Direct transmission, where transducers are placed on opposite faces of the concrete member, is the most satisfactory method (Clause 6.3.1).