Rebound Hammer Test
Your structural audit or quality inspection report needs a rebound hammer test result — and your approving authority will not accept it from a non-NABL lab. Jancy Labs conducts rebound hammer testing per IS 516 Part 5 Sec 4 with reports signed by a qualified Materials Engineer.
Get your rebound hammer test done today — contact us.
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WHAT IS A REBOUND HAMMER TEST?
The rebound hammer test tells you the surface hardness and estimated compressive strength of an existing or newly cast concrete element — without cutting or damaging the structure. Structural engineers and building auditors use this test to quickly screen columns, beams, slabs, and walls for quality compliance on active project sites. Skipping this test on a rehabilitation or quality audit project means your structural assessment report lacks the IS 516-compliant data that CPWD and TNHB specifically require for approval.
APPLICABLE STANDARDS
Jancy Labs conducts rebound hammer testing strictly as per the following standard:
- IS 516 Part 5 Sec 4 — EXT LINK: IS 516 Part 5 Sec 4 on BIS → https://www.bis.gov.in — This standard specifies the exact procedure for rebound hammer testing of hardened concrete, including number of readings, surface preparation, and result interpretation. Jancy Labs follows IS 516 Part 5 Sec 4 without deviation — consequently, every report we issue is fully defensible at audit or approval stage.
Note: No ASTM equivalent is applicable for this test scope. IS 516 Part 5 Sec 4 is the governing standard for all government department submissions in Tamil Nadu.
WHY THIS TEST MATTERS
Specifically, the rebound hammer test delivers project consequences far beyond a simple number on a page:
- Structural audits require it — CPWD and TNHB mandate IS 516 Part 5 Sec 4 compliant rebound hammer data for existing-structure rehabilitation approvals. Furthermore, missing this data stalls your submission entirely.
- Quality control on new pours — Contractors use rebound hammer readings to verify concrete surface hardness before form stripping. Consequently, early detection of weak zones saves costly rework.
- Tender and DPR documentation — PWD Tamil Nadu and CMDA require rebound hammer test data in Detailed Project Reports for structural interventions. Therefore, you need a NABL-signed report, not a site observation note.
- MES and BRO defence projects — Military Engineeing Services and Border Roads Organisation accept only NABL-accredited NDT reports for structural assessment. Additionally, non-NABL results are rejected outright at their quality audit stage.
- Smart Cities and ULB retrofitting — Urban local body projects funded under Smart Cities missions require NDT reports from accredited labs to satisfy central government audit requirements. Moreover, rebound hammer data feeds directly into structural fitness certificates.
- Insurance and litigation support — In building failure investigations, rebound hammer test data from a NABL-accredited lab carries legal evidentiary weight. Non-accredited data, however, is routinely dismissed.
Submitting rebound hammer data from an uncalibrated or non-NABL instrument voids the result entirely and exposes you to tender disqualification.
WHY CHOOSE JANCY LABS FOR REBOUND HAMMER TESTING?
At Jancy Labs, our Schmidt hammer is NABL-calibrated to IS 516 Part 5 Sec 4 — so your rebound number stands up at every approval desk.
- Calibrated Schmidt rebound hammer — serviced and verified against NABL calibration standards
- Rebound hammer test conducted strictly per IS 516 Part 5 Sec 4 — minimum 9 readings per test area, outliers discarded per standard
- Every rebound hammer report signed by a Authorized Engineer
- NABL accredited lab vide TC-12176 | ISO 17025:2017
- NHAI, Railways, AAI, CPWD, TNHB, and PWD Tamil Nadu accept our rebound hammer reports for structural audits and rehabilitation projects
- Trusted for rebound hammer testing by structural consultants, contractors, and government project engineers across Tamil Nadu
HOW TO GET YOUR TEST DONE
Step 1 — Send Your Sample or Schedule On-Site Testing
The rebound hammer test requires testing directly on the concrete surface — on the structure itself or on extracted concrete cores at our Madurai laboratory. Therefore, most rebound hammer assignments involve our team visiting your site.
on-site testing:
| Item | Requirement |
|---|---|
| Scope confirmation | Number of elements, test locations, structural element types |
| Surface condition | Clean, dry, free of loose material — we advise on preparation |
| Access | Safe scaffolding or access platform for elevated elements |
| Site address | Share exact location and site contact before mobilisation |
Step 2 — We Test It
Our Materials Engineer selects the test grid on your concrete element and marks the rebound hammer test positions as per IS 516 Part 5 Sec 4. Subsequently, we record a minimum of 9 rebound readings per test area, discard values deviating more than 6 units from the median, and calculate the average rebound number. A qualified Materials Engineer oversees every rebound hammer test and reviews the results before report preparation begins.
Turnaround: Report ready within 2–3 working days of test completion.
Step 3 — You Receive Your Certified Report
OUR REBOUND HAMMER TEST PROCESS — AS PER IS 516 PART 5 SEC 4
Preparing for the Rebound Hammer Test
- First, our Materials Engineer reviews the structural drawing and identifies all test locations per your project scope.
- Next, we clean the concrete surface — removing paint, laitance, or loose material — to ensure hammer contact meets IS 516 Part 5 Sec 4 requirements.
- Then, we mark a minimum 9-point test grid on each element, spaced at least 25mm apart and 25mm from any edge.
Finalising the Rebound Hammer Results
- Subsequently, our engineer presses the Schmidt hammer perpendicular to the surface and records each rebound number — repeating across all marked grid points.
- Next, we discard any reading that deviates more than 6 units from the median value, as IS 516 Part 5 Sec 4 specifies.
- Then, we calculate the average rebound index from the remaining valid readings.
- Consequently, we correlate the average rebound number to estimated compressive strength using the IS 516 correlation chart applicable to your cement and aggregate type.
- Finally, a qualified Materials Engineer reviews every rebound hammer result, interprets the findings against your concrete grade, and signs the report before we dispatch it.
FREQUENTLY ASKED QUESTIONS
How long does a rebound hammer test take at Jancy Labs?
On-site rebound hammer testing typically takes 1–2 hours per structural element, depending on the number of test points your IS 516 Part 5 Sec 4 scope requires. Jancy Labs dispatches the signed report within 2–3 working days of completing the test. Therefore, you can plan your project timeline with confidence.
Can I send samples by courier to Jancy Labs for a rebound hammer test?
The rebound hammer test requires testing directly on the concrete structure or on concrete cores at our Madurai laboratory. Consequently, most rebound hammer assignments involve field testing at your project site. Call +91-8680049004 to discuss whether on-site testing or core-based laboratory assessment suits your project better.
Is your rebound hammer test report accepted by CPWD, NHAI, Railways, AAI, PWD?
Yes. All Departments accept our rebound hammer test reports because Jancy Labs holds NABL accreditation TC-12176 under ISO 17025:2017. Additionally, every report carries the signature and stamp of a qualified Materials Engineer, which these departments specifically require for structural audit submissions.
Do you conduct rebound hammer testing on existing structures and new construction?
Yes. Jancy Labs conducts rebound hammer tests on both existing structures — for rehabilitation and audit purposes — and newly cast concrete elements for quality control. Furthermore, we cover columns, beams, slabs, walls, and foundations across residential, commercial, and infrastructure projects throughout Tamil Nadu.
How many readings do you take for a rebound hammer test?
As per IS 516 Part 5 Sec 4, Jancy Labs takes a minimum of 9 readings per test location and discards outliers that deviate more than 6 units from the median. Therefore, the final rebound number represents a statistically valid surface hardness value for that concrete element. Additional test points are available on request for comprehensive structural audits.
Ready to commission your rebound hammer test?
Your structural audit or quality report needs IS 516 Part 5 Sec 4 compliant data — and your approving authority will only accept it from a NABL-accredited lab. Send your requirement today and receive a quote within 24 hours.
| Contact | Details |
|---|---|
| Phone | +91-8680049004 / +91-9994421275 |
| +91-8680049004 | |
| jancylabsmdu@gmail.com | |
| Address | No.6, Ganesh Nagar 3rd Street, K.Pudur, Madurai — 625007 |
| Hours | Monday to Saturday, 10:00 AM – 6:00 PM |
RELATED SERVICES
- Ultrasonic Pulse Velocity (UPV) Test — Non-destructive assessment of concrete homogeneity and void detection per IS 516 Part 5 Sec 1
- Concrete Core Compressive Strength Test — Destructive verification of in-situ concrete strength for structural audit and rehabilitation approval
- Concrete Cube Compressive Strength Test — Standard quality control test for fresh concrete per IS 516, accepted by all approving departments