IS 516:2022 Part 5/Sec 4 is the Indian Standard (BIS) for methods of tests for strength of concrete - part 5: non-destructive testing of hardened concrete - section 4: ultrasonic pulse velocity. This standard details the Ultrasonic Pulse Velocity (UPV) method for non-destructive testing of hardened concrete. Engineers use it to assess the uniformity, detect internal flaws like honeycombing or cracks, and estimate the overall quality and compressive strength of concrete in existing structures.
Covers the method for assessing the quality and uniformity of concrete and estimating its strength using ultrasonic pulse velocity.
Quick Reference — IS 516 Part 5 Sec 4:2022 Half-Cell & Resistivity
Half-cell potential bands, resistivity bands, electrode types and grid spacing for in-situ corrosion assessment.
| Reference | Value | Clause |
|---|
| Test covered | Half-cell potential — corrosion of reinforcement | Cl. 1 (Scope) |
| Reference electrode — common | Cu/CuSO4 (CSE) / Ag/AgCl | Cl. 5.1 |
| Wetting — surface | Pre-wet for ≥ 5 min before reading | Cl. 6.3 |
| Spacing — measurement grid | 150–300 mm centres (typical) | Cl. 6.4 |
| Potential band — > −200 mV (CSE) | >90 % probability NO corrosion | Cl. 8 (Table 1) |
| Potential band — −200 to −350 mV | Uncertain (intermediate) | Cl. 8 (Table 1) |
| Potential band — < −350 mV (more negative) | >90 % probability of corrosion | Cl. 8 (Table 1) |
| Connection to rebar — required | Yes — chip + electrical clip to bar | Cl. 6.2 |
| Concrete resistivity test (companion) | Wenner 4-probe resistivity measurement | Cl. 9 / Annex |
| Resistivity — > 100 kΩ·cm | Negligible corrosion risk | Annex (Table) |
| Resistivity — 50–100 kΩ·cm | Low risk | Annex (Table) |
| Resistivity — 10–50 kΩ·cm | Moderate to high risk | Annex (Table) |
| Resistivity — < 10 kΩ·cm | Very high corrosion risk | Annex (Table) |
| Chloride / carbonation — separate destructive test | Drilled powder samples per IS 14959 / phenolphthalein | |
| Reporting — equipotential contour map | Recommended for slab/wall surveys | Cl. 7 |
⚠ Bands assume Cu/CuSO4 (CSE) reference. Convert if Ag/AgCl used. Always combine with chloride/carbonation tests for full corrosion diagnosis.
Overview
- Status
- Current
- Usage level
- Frequently Used
- Domain
- Structural Engineering — Testing Methods and Quality Control
- Type
- Testing Method
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Practical Notes
! Direct transmission (placing transducers on opposite faces) yields the most accurate and reliable results and should be preferred over semi-direct or indirect methods.
! Measurements taken parallel to reinforcing steel can yield artificially high velocities because sound travels faster in steel (approx. 5.9 km/s) than in concrete. Tests should ideally be conducted avoiding rebars or perpendicular to them.
! A proper couplant must be applied to ensure a zero-air-gap contact between the transducer face and the concrete surface; otherwise, the ultrasonic pulses will not penetrate effectively.
Frequently referenced clauses
concretehardened concretereinforced concrete
International Equivalents
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International Comparison — Coming Soon
We're adding equivalent international standards for this code.
Key Values6
Quick Reference Values
Excellent concrete quality velocity> 4.5 km/s
Good concrete quality velocity3.5 to 4.5 km/s
Doubtful concrete quality velocity3.0 to 3.5 km/s
Poor concrete quality velocity< 3.0 km/s
Standard transducer frequency for concrete50 kHz to 150 kHz
Pulse velocity of steel reinforcement (approximate)5.9 km/s
Key Formulas
V = L / T — Pulse velocity (km/s), where L is path length and T is transit time
Tables & Referenced Sections
Key Tables
Table 1 - Velocity Criterion for Concrete Quality Grading
Key Clauses
Clause 5 - Apparatus and Transducers
Clause 6 - Test Procedure (Direct, Semi-direct, and Indirect transmission)
Clause 7 - Determination of Pulse Velocity
Clause 8 - Influence of Test Conditions (Moisture, Temperature, Reinforcement)
Frequently Asked Questions4
What pulse velocity indicates good quality concrete?+
A pulse velocity between 3.5 km/s and 4.5 km/s generally indicates good quality concrete.
What are the three ways to arrange transducers for a UPV test?+
Direct transmission (opposite faces), Semi-direct transmission (adjacent faces), and Indirect or surface transmission (same face).
How does moisture affect UPV readings?+
Wet concrete typically yields slightly higher pulse velocities (by about 2% to 5%) compared to dry concrete of the same quality.
Can UPV determine exact compressive strength?+
No, UPV is a qualitative test used to assess uniformity and relative quality. To estimate actual compressive strength, it must be correlated with core tests or combined with the Rebound Hammer test (SONREB method).
QA/QC Inspection Templates
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QA/QC templates coming soon for this code.