Concrete NDT

Compressive
Strength Testing MPa

Silver Schmidt hammer rebound testing for MPa to AS/ASTM standards — rapid, non-destructive in-situ strength estimation.

MPa

Strength Units

C805 / D5873

Standards

In-situ

No Coring

Method

Schmidt Hammer
Rebound Technique

The Schmidt hammer evaluates the rebound of a spring-loaded mass that strikes the concrete surface. It delivers an impact with a specific energy level, and the rebound distance varies based on the concrete's surface hardness — which correlates with compressive strength.

Using the provided conversion chart, the rebound measurement is translated into an estimate of compressive strength expressed in kPa or MPa. Our testing protocols, data analysis and reporting comply with ASTM C805-02 and ASTM D5873 industry standards.

This testing approach is well-suited for evaluating the on-site uniformity of concrete, identifying areas of substandard quality or degradation, and approximating the progression of in-situ strength over time.

How It Works

Spring-loaded mass impact

Hammer plunger is pressed against the prepared concrete surface, compressing an internal spring

Rebound distance measured

When released, the mass strikes the surface; the rebound distance R is recorded by the device (scale 10–100)

Conversion to strength

The rebound number R is converted to MPa via the manufacturer calibration chart, corrected for impact direction and angle

Statistical analysis

Minimum 10 readings per test location; outliers removed; mean and standard deviation reported per zone

Applications

When Strength
Testing is Required

Strength measurements are needed for a range of purposes — from quick quality verification on fresh pours to evaluating the residual capacity of aging infrastructure before reuse or sale.

QA/QC quality verification on new pours and construction works
Evaluating hardness and conformance of new concrete placements
Assessing structural conditions and residual strength in aging structures
Accommodating changes in slab loading or functional repurposing
Initial evaluation of in-situ strength prior to coring or load testing
Structural auditing and service life assessments
Pre-purchase structural evaluations and due diligence
Pre-insurance assessments for insurers, banks and guarantors

Wharf Deck Slab Compressive Strength MPa Contour Map Tasmania & Victoria

Wharf Deck Compressive Strength (MPa) Contour Map with warm colors indicating zones of lower strength

Reporting Output

Strength
Distribution Maps

Test results are spatially organised by structural element and zone, producing strength distribution maps that immediately identify conforming and non-conforming areas — enabling targeted intervention rather than blanket remediation.

Typical Report Contents

Deliverable	Detail
Rebound data table	Raw R values, corrected readings, and MPa estimates per test point
Strength map	Colour-graded plan showing strength distribution across the structure
Zone statistics	Mean, standard deviation and characteristic strength per test zone
Standards compliance	Comparison against specified design strength or acceptance criteria
Recommendations	Zones requiring further investigation, coring, or remediation

ASTM C805-02

Standard test method for rebound number of hardened concrete

ASTM D5873

Rock hardness by rebound hammer — dynamic elastic properties and penetration resistance

Visual Inspection GPR Structural Imaging Corrosion Testing Pile Integrity Testing Request Testing

CompressiveStrength Testing MPa

Schmidt HammerRebound Technique

When StrengthTesting is Required

StrengthDistribution Maps

Areas WeServe in Tasmania

Compressive
Strength Testing MPa

Schmidt Hammer
Rebound Technique

When Strength
Testing is Required

Strength
Distribution Maps

Areas We
Serve in Tasmania