Schmidt Hammer Testing
In-Situ Surface Hardness and Indicative Strength Assessment
Overview
The Schmidt rebound hammer measures concrete surface hardness by firing a spring-loaded mass against the surface and recording the rebound distance. The rebound number provides an indication of near-surface quality and, through established correlations, an estimate of compressive strength.
The primary value in SiteOps investigations is comparative rather than absolute. By systematically testing across a structure, areas of relatively lower hardness can be quickly identified and targeted for more detailed investigation.
Schmidt hammer testing is rapid (under one minute per location), portable, and requires no power supply. It is the fastest way to obtain in-situ quality indication across large numbers of locations.
For strength assessment, SiteOps does not rely on rebound hammer results alone — core testing provides the definitive data for structural calculations.
Applications
Concrete Quality Screening
Rapid assessment of relative quality across large areas.
Fire Damage Assessment
Assessing concrete surface degradation following fire events.
Quality Uniformity Mapping
Identifying areas of potentially poor compaction or curing.
Core Location Selection
Using rebound results to guide core extraction locations.
Technical specifications
| Impact Energy | 2.207 Nm (N-type hammer) |
|---|---|
| Rebound Scale | 10–100 (typical range 20–50) |
| Test Protocol | 12 impacts per location |
| Affected Zone | Surface 30–50mm depth |
| Standards | AS 1012.4, ASTM C805, BS EN 12504-2 |
Related technologies
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FAQ
Common questions
How reliable is Schmidt hammer for strength?+
It provides a rough indication with ±25% uncertainty. SiteOps uses it for screening, not as a substitute for core testing.
Deploy Schmidt on your asset
Share drawings, exposure conditions, and programme constraints — we will propose an investigation scope aligned to Australian standards and your risk profile.
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