Compression Testing Machine Calibration
(CTM Calibration — IS 14858 / ISO 7500-1)
NABL-accredited on-site calibration of Compression Testing Machines (CTM) per IS 14858 and ISO 7500-1 — mandatory for NABL laboratories testing concrete cube/cylinder compressive strength per IS 516.
What is the Compression Testing Machine Calibration?
The Compression Testing Machine (CTM) is the most widely used testing machine in construction material labs — used for concrete cube compression (IS 516), brick compressive strength (IS 3495), paver block, core and cylinder testing. IS 14858 (Method for Verification of Compression Testing Machines used for Testing Concrete) specifies calibration requirements specific to CTMs used in concrete testing.
At Global Lab, CTM calibration per IS 14858 and ISO 7500-1 verifies force accuracy at multiple load points, checks platens for flatness and parallelism, verifies the loading rate indicator, and checks the zero load reading — using NPL-traceable reference load cells. Class 1 (±1%) calibration is required for NABL-accredited laboratories per IS 516 testing. Calibration is on-site at client location.
Non-Destructive
Fast Turnaround
NABL Certified
Pan-India Coverage
Digital Reporting
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Compression Testing Machine Calibration — Site Images
How the Compression Testing Machine Calibration is Conducted
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1
Surface Preparation
A shallow groove (approx. 25mm deep) is cut into the concrete surface using a diamond-tipped cutting tool. The surface is cleaned of dust and debris. -
2
Insert Disc Placement
A specially designed steel insert disc is placed into the groove. A thin rod connects the disc to the pullout apparatus above the surface. -
3
Hydraulic Pullout Force Application
A hydraulic jack applies a steady, controlled pullout force to the insert disc via the reaction ring resting on the concrete surface. -
4
Failure Load Recording
The maximum force at which the concrete cone is extracted is recorded. A digital load indicator provides real-time readings with data logging. -
5
Strength Calculation & Reporting
The pullout force is correlated to cube compressive strength using established calibration curves. NABL-accredited reports are issued via Autovity QLMS.
Applicable Test Standards
| Standard | Title | Scope | Type |
|---|---|---|---|
| IS 14858 | Method for Verification of Compression Testing Machines used for Testing Concrete | CTM Calibration | Indian Standard |
| ISO 7500-1 | Metallic Materials — Calibration of Static Uniaxial Testing Machines | Force Calibration | ISO |
| IS 516 | Methods of Tests for Strength of Concrete | Concrete Testing | Indian Standard |
| NABL-141 | NABL Policy on Metrological Traceability of Measurement Results | Traceability | NABL |