In-Situ Concrete Strength Assessment(IS 13311 · IS 516 Part 4)
Combined-method assessment of in-place concrete strength — rebound hammer and ultrasonic pulse velocity per IS 13311, anchored by core extraction and testing per IS 516 (Part 4) — for structures whose cube records are missing, doubted or expired.
What is In-Situ Concrete Strength Assessment?
When cube records are missing, disputed, or simply too old to describe today's structure, the concrete must speak for itself. Indian practice combines three evidence streams: rebound hammer (IS 13311 Part 2) for surface hardness mapping, ultrasonic pulse velocity (IS 13311 Part 1) for integrity and uniformity, and — where decisions carry structural weight — extracted cores tested per IS 516 (Part 4):2018, the direct strength anchor that calibrates the NDT grid.
Global Lab grids the structure, maps rebound and UPV values, targets core locations from the NDT picture, and reports characteristic in-situ strength with the combined-method correlation — the deliverable that audits, retrofitting designs and change-of-use approvals actually require.
How the In-Situ Concrete Strength Assessment is Conducted
- 1
Structure Gridding
Members are gridded and test locations marked covering the structural system representatively. - 2
Rebound Hammer Survey
Surface hardness is mapped per IS 13311 (Part 2) with orientation corrections and calibrated hammers. - 3
UPV Survey
Pulse velocities are measured per IS 13311 (Part 1) in direct/semi-direct modes, mapping integrity and honeycombing. - 4
Core Extraction & Testing
Cores are drilled at NDT-informed locations, prepared and tested per IS 516 (Part 4):2018 with strength corrections applied. - 5
Combined Interpretation
NDT grids are calibrated against core strengths; characteristic in-situ strength is derived member-wise. - 6
Reporting
Strength maps, core certificates and the combined assessment are issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 13311 (Pt 2):1992 | Non-Destructive Testing of Concrete — Rebound Hammer (Reaffirmed) | Surface Hardness | Indian Standard |
| IS 13311 (Pt 1):1992 | Non-Destructive Testing of Concrete — Ultrasonic Pulse Velocity (Reaffirmed) | Integrity / Uniformity | Indian Standard |
| IS 516 (Pt 4):2018 | Hardened Concrete — Methods of Test — Sampling, Preparing and Testing of Concrete Cores | Core Strength Anchor | Indian Standard |
| IS 456:2000 | Plain and Reinforced Concrete — Code of Practice | Acceptance Context | Indian Standard |