What Are the Essential Concrete Testing Methods in Ontario?

Concrete is a key material in foundations, slabs, and structural elements. In Ontario’s climate—with frequent freeze–thaw cycles and rapid temperature changes—verifying concrete quality is essential to ensure long-term performance.

Concrete testing methods confirm that both fresh and hardened concrete meet required strength, durability, and code standards under OBC and CSA A23.1/A23.2.

Why Concrete Testing Matters

Even small variations in mix proportions, temperature, or placement conditions can significantly affect performance. Proper testing helps prevent:

• Premature cracking

• Surface scaling during winter

• Low compressive strength at 7 or 28 days

• Moisture-related issues in slabs

• Costly repairs or delays

Consistent and standardized concrete testing methods are essential in every project.

Testing Fresh Concrete (On-Site)

Fresh concrete is tested immediately upon delivery to ensure the mix meets project specifications.

1. Temperature Test

A probe thermometer is inserted into the fresh mix to record temperature. This matters because:

• Temperature influences curing rate and strength development

• Cold or hot mixes may not meet performance requirements

• Recording temperature is required for each batch

2. Slump Test (Workability Assessment)

The slump test evaluates workability and consistency.

• High slump may indicate excess water

• Low slump can make placement difficult

• Required for nearly all structural pours

3. Sampling for Strength Testing

Although cube samples are common globally, Ontario follows the standard test method for compressive strength of cylindrical concrete specimens.

Regardless of format:

• Samples are molded on-site

• Cured under controlled conditions

• Tested at 7 and 28 days

• Used to confirm actual compressive strength

This remains one of the most critical concrete strength testing methods on structural projects.

Testing Hardened Concrete (Post-Construction)

Once the concrete hardens, additional tests help assess in-place quality and identify potential issues.

4. Rebound Hammer Test (NDT)

A quick non-destructive method that measures surface hardness. Useful for:

• Comparing different areas of the same structure

• Identifying weak zones on beams, slabs, or walls

• Preliminary condition assessments

5. Ultrasonic Pulse Velocity (UPV) Test (NDT)

UPV uses sound waves to evaluate internal consistency. It is one of the most reliable non-destructive testing methods for detecting:

• Internal cracks

• Voids or honeycombing

• Changes in material density

  
  

UPV is often used together with the rebound hammer for improved accuracy.

6. Drilled Core Test (Destructive)

A cylindrical core is extracted from hardened concrete and tested directly in the lab. This method is typically used when:

• Field samples fail

• Assessing older structures

• Verifying structural performance during renovations

It is often considered the most accurate in-place strength measurement method.

Common Issues Observed on Job Sites

• Not performing air-content tests in cold weather

• Taking samples only from the beginning of a pour

• Incomplete temperature records

• Improper labeling or curing of samples

• Skipping moisture testing on slabs with planned finishes

These oversights can compromise long-term durability.

Ontario Requirements: At a Glance

• Minimum one compressive strength test per 100 m³

• Slump, temperature, and air content checked for each batch

• All procedures must follow CSA A23.2

• Additional moisture testing may be needed for flooring systems

• Proper documentation is required for municipal and engineering review

Final Thoughts

Concrete testing ensures that materials placed on site will perform as intended under Ontario’s conditions. By combining field checks and standardized lab procedures, projects achieve reliable, long-term results.

At Parsways Inc., our engineers apply CSA-compliant testing practices to verify that each concrete element meets its required performance throughout the structure’s lifespan.

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FAQs

Is the slump test required for structural concrete?

Yes, it’s performed on almost all structural pours to confirm workability.

What’s the difference between non-destructive and core testing?

NDT checks concrete without damage; core tests remove a sample for lab strength verification.

When should core testing be used instead of cylinder strength results?

When field cylinders fail, or when evaluating existing or older concrete structures.