Post Takeaways

To understand how to know and ensure that Chockfast grout and chock products work the way they are intended in the field using this troubleshooting guide.

Basic Outline

1. Introduction
2. Using Hardness to Approximate Grout Compressive Strength
3. Compressive Strength Evaluation of Grouts and Chocks
4. Reviewing Results of Compressive Strength Evaluations
5. Considerations for the Installer
6. Final Thoughts

 Introduction

On-Site Grout Testing Best Practices for Reliable Chockfast Results

In our last post, Chockfast Essentials: Pot Life and Cure Time Explained, we covered the timing basics for installing Chockfast grout. Now, let’s talk about what comes next—how to confirm your installation is solid without cutting into the foundation.

Whether you’re an installer, engineer, or designer, understanding grout testing procedures and on-site grout testing methods is essential for ensuring long-term performance and reliability.

Why Chockfast Grout Validation Matters

Chockfast epoxy grouts and chocks are essential for keeping heavy equipment foundations solid and secure. But once they’re in place, you can’t exactly pull a sample from under a machine to test it. That’s where non-destructive testing and field-cast samples come in. They’re your go-to tools for confirming the job was done right.

Using Hardness to Approximate Grout Compressive Strength

Barcol Hardness: A Quick & Practical On-Site Verification Method

One of the easiest ways to test on-site is with a Barcol Hardness test. It’s a quick, non-destructive way to check how well the epoxy has cured.

• Standard: ASTM D2583
• Best for: Two-part epoxy chocks like Chockfast Orange
• Recommended device: Barcol Impressor® GYZJ-934-1
• Not ideal for: Three-part grouts with large aggregates

⚠️ Heads up: Barcol readings don’t directly measure compressive strength. It’s a simple and practical way to confirm the material has cured sufficiently to move forward. Barcol provides a direct relationship between degree of cure and compressive strength that’s predictable.

For example, if Chockfast Orange hits a Barcol reading of 35 or more, the user can tell the product has reached close to 75% of its strength, indicating it’s ready for moving forward—anchor bolts can be tensioned, and equipment can be started.

Compressive Strength Evaluation of Grouts and Chocks

Compressive Strength Testing: The Gold Standard

For high-load applications, compressive strength is the most thing to check. This test is typically performed on field-cast samples cured under the same conditions as the actual installation and then tested in the lab using a reliable and calibrated load unit such as an Instron. Unlike the Barcol test, measuring the compression is a more complex and destructive test that requires precise sample preparation and industry standardized test methods.

Here’s how a compressive test results guide would break it down:

• ASTM D695 – For two-part epoxy chocks like Chockfast Orange, Gray, and Black
• ASTM C579 – For three-part epoxy grouts like Chockfast Red, Escoweld 7505E/7530, and Chockfast Red Versaflow. Check out this Simple Guide to ASTM C579 blog on from Forney Resources on the details of performing testing to this standard.

Because these tests are destructive, they are done on separate prepared samples, not the actual installation. With this in mind, these cast prepared samples won’t cure exactly the same as the material under the machine due to the mass effect from the heat of reaction in the chemistry. (Check out our blog on Explaining the Epoxy Cure Cycle of Chockfast® Epoxies for more on that.)

✅ On-site compressive test Pro tip: To get more accurate results, samples are often post-cured to simulate the heat buildup in real installations. This tweak is widely accepted in the industry and helps match lab results to real-world performance.

Reviewing Results of Compressive Strength Evaluations

Common Testing Pitfalls to Avoid

If your test results don’t line up with expectations, here are some common construction test troubleshooting recommendations to consider:

• Post-curing mismatch: Comparing post-cured samples to non-post-cured ones can throw off your numbers.
• Wrong load rate: Stick to 0.1–0.125 × sample height (in inches) or 0.2–0.25 in./min.
• Aggregate changes: Reducing aggregate by just half a bag can drop strength by 5–7%.
• Cold temps: Low temperatures slow or even stop the cure. (For more info, see our Critical Machinery Installation in Cold Weather? Find Out How to Plan for Success.)
• Uneven surfaces: Test samples need to be flat and square. Use a precision grinder to prep them properly.
• Wrong test method: Don’t use cement-based standards like ASTM C109 for epoxy products—they’re not compatible.

Considerations for the Installer

Best Practices for Reliable Results and Structural Grout Performance

• Work with experienced labs: Not all labs know epoxies. Share the correct ASTM standards and product guides.
• Keep good records: Track batch numbers, temperatures, and install conditions. Our Chockfast Job Tracker can help.
• Follow the product and manufacturer instructions: Stick to the mixing and installation guidelines to avoid compromising your results. Chockfast grout troubleshooting guides go beyond helping your team to navigate pitfalls and also offer pro tips on how to successfully achieve the results your team needs.

Final Thoughts on On-Site Grout Testing

While you can’t run significant quantitative tests on the actual grout under your equipment, there are reliable test methods that provide reliable ways to validate your installation. By following the manufacturer’s instructions on storage, application use, and proven testing techniques, such as discussed here, you can be confident your Chockfast installation is built to last.

Need more info? Visit itwpp.com and check out our technical datasheets and guides. Reach out to our ITW Performance Polymers Technical Services team or your local Chockfast Worldwide Distributor Network representative. We’re here to help.

To discuss how long you have to place Chockfast precision epoxy grouts or chocks or any of our heavy machinery installation adhesives, please contact ITW Performance Polymers Technical Services or your local Chockfast Worldwide Distributor Network representative.

View all our Technical Data Sheets and Safety Data Sheets. Need some help? Ask a technical question and find a solution!   

Further reading: Cheat Sheet: Chockfast^® Epoxy Grout Typical Installation Steps and Critical Machinery Installation In Cold Weather? Find Out How To Plan For Success.

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