Windsor Probe Test

The Windsor Probe Test is a semi-destructive method for evaluating the in-place compressive strength of concrete. A hardened steel alloy probe is driven into the concrete surface at high velocity by a precisely measured explosive charge. The depth of penetration — measured from the surface to the top of the exposed probe — is inversely proportional to the concrete’s resistance and correlates to compressive strength.

Because the probe engages the concrete matrix and coarse aggregate rather than just the surface, the Windsor Probe generally provides a more representative strength estimate than the rebound hammer, particularly on well-cured or older concrete.

Test Standards We Follow

ASTM C803

US standard for penetration resistance of hardened concrete. The internationally recognised reference standard for probe testing methodology and interpretation.

MS 26 Part 3

Malaysian Standard for penetration testing of concrete, ensuring alignment with local specifications for JKR and CIDB projects.

When Is Windsor Probe Testing Used?

In-situ compressive strength verification
Verify actual strength of hardened concrete in its final structural position, not just from lab-cured samples.
Investigation of low cube test results
Determine whether concrete in place meets specification when routine cube tests indicate under-strength results.
Where surface-only tests are insufficient
Assess concrete quality where rebound hammer readings alone are considered inadequate, particularly on carbonated surfaces.
Applicable to fresh and mature concrete
The probe system supports both new construction and long-established structures with appropriate calibration.
Pre-load verification for structural modifications
Confirm concrete capacity before adding loads, changing use, or modifying structural elements.
Assessment of older or heritage concrete structures
Provides more reliable strength estimates than rebound hammer on aged concrete where surface conditions may not reflect the interior.

How the Test Works

Step 1 — Site Preparation
The test area is selected on sound, non-carbonated concrete free of visible defects. Cover meter checks are performed to avoid firing into reinforcement.
Step 2 — Equipment Setup
The Windsor Probe driver is loaded with a calibrated powder charge appropriate to the expected concrete strength range.
Step 3 — Probe Firing
The probe is fired into the concrete surface perpendicular to the plane. A triangular pattern of three probes is typically fired per test location.
Step 4 — Measurement
The exposed length of each probe above the concrete surface is measured with the supplied gauge to 0.1 millimetre precision.
Step 5 — Averaging and Correction
Readings are averaged. Aggregate hardness correction based on the Mohs scale is applied to the mean penetration value.
Step 6 — Strength Estimation
Compressive strength is read from the calibration table specific to the aggregate type used in the concrete.

Why Foundtest for Windsor Probe Testing?

Certified Windsor Probe equipment with calibrated powder charges
Trained operators handling explosive-driven testing safely per manufacturer specifications
Cover meter pre-scan to avoid firing into reinforcement
Reports referencing both ASTM C803 and MS 26 Part 3
Full safety protocols including exclusion zones and PPE compliance
Available as a combined package with rebound hammer for cross-verification

Frequently Asked Questions

Is the Windsor Probe Test destructive?

It is classified as semi-destructive. The probe embeds in the concrete leaving a small hole approximately 8 millimetres in diameter, which can be patched afterwards. Structural integrity of the tested element is not affected.

When would you choose Windsor Probe over rebound hammer?

When higher accuracy is required, when the concrete surface is carbonated, or when the rebound hammer readings need corroboration. It is also preferred on older concrete where surface conditions may not reflect the interior strength.

Is the explosive charge safe?

Yes, when handled by trained operators using the manufacturer’s approved charges. Site safety measures are always applied, including exclusion zones, PPE, and pre-firing area clearance.

Do you need to know the aggregate type?

Yes. Aggregate hardness on the Mohs scale significantly affects probe penetration depth. We record the aggregate type on site and apply the appropriate correction factor per ASTM C803 to give accurate strength estimates.

Can Windsor Probe replace core testing?

For most quality-assessment purposes, yes. For legally definitive strength determinations — such as court cases or major disputes — laboratory testing of extracted cores remains the gold standard.

Book Windsor Probe Testing

Contact Foundtest for Windsor Probe testing anywhere in Malaysia. Call +603-8051 5333, WhatsApp us, or use the contact form for a same-day quote.

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Windsor Probe Test

Test Standards We Follow

ASTM C803

MS 26 Part 3

When Is Windsor Probe Testing Used?

In-situ compressive strength verification

Investigation of low cube test results

Where surface-only tests are insufficient

Applicable to fresh and mature concrete

Pre-load verification for structural modifications

Assessment of older or heritage concrete structures

How the Test Works

Step 1 — Site Preparation

Step 2 — Equipment Setup

Step 3 — Probe Firing

Step 4 — Measurement

Step 5 — Averaging and Correction

Step 6 — Strength Estimation

Why Foundtest for Windsor Probe Testing?

Certified Windsor Probe equipment with calibrated powder charges

Trained operators handling explosive-driven testing safely per manufacturer specifications

Cover meter pre-scan to avoid firing into reinforcement

Reports referencing both ASTM C803 and MS 26 Part 3

Full safety protocols including exclusion zones and PPE compliance

Available as a combined package with rebound hammer for cross-verification

Frequently Asked Questions

Book Windsor Probe Testing

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