Why Concrete Testing Shouldn’t Be an Afterthought

Concrete is so central to modern construction projects that its safety, strength, and reliability are assumed by default. Indeed, concrete’s status, stretching to ancient Rome and beyond, is so well established that it’s easy to treat concrete testing as a checklist item to check off without a lot of thought.

That’s unfortunate because concrete testing is fundamental to assessing the structural integrity of buildings, bridges, roadways, and other construction projects. A botched concrete test could miss flaws that render a building uninhabitable and impose substantial liability on contractors and concrete suppliers.

Of course, construction industry professionals realize the risks of inadequate concrete testing. The smart ones don’t neglect it, but they might not fully grasp how readily inadequacies crop up under certain conditions.

CTL Engineering has been testing concrete for 90 years, which gives us a rare insight on the vulnerabilities of concrete testing. Learning about these vulnerabilities is essential for safety-minded construction professionals.

Concrete testing must be done well

Yes; there are established, respected concrete testing standards. And it’s true that concrete testing technicians need to be certified. Furthermore, exacting concrete specifications can be spelled out for suppliers and builders.

The trouble is that all these safeguards still leave a lot to chance. Here are just a few examples:

• Sampling methods: Concrete samples can be taken from different locations — at the truck, in the placement site, after the pump, even after the paver, etc. — while the concrete remains fresh and plastic . Each of these sources can be strictly specified by national standard or project documents. The timing, consolidation, and atmospheric conditions can influence test results. Experienced testing technicians must weigh all these variables.
• Temperature: A tight temperature range (which is difficult to comply with in a real-world construction environment) may require on site curing equipment. Testing technicians must be careful to ensure test samples remain within the proper temperature range required for an accurate test.
• Specifications vs. reality: It’s not exactly safe to assume concrete placement, consolidation, finishing, and curing will match project specifications. Each of these points in the construction process introduces the potential for slight deviations from the specifications.

These variables illustrate the need for comprehensive testing by experts who understand the many subtleties of concrete and construction.

Testing partners must be reputable

Testing technicians should have a thorough array of testing equipment which can be used in the lab and on-site to assess both short- and long-range concrete characteristics.

CTL’s engineers have a solid grounding in the science of concrete mixing, curing, drying, and more. Our concrete tests include:

• Mix designs
• Compressive strength and air content
• Consistency and yield
• Flexural and split tensile strength
• Modulus of elasticity
• Drying shrinkage
• Rapid chloride permeability

(For an in-depth look at one of our concrete-testing services, see 5 Factors to Consider when Performing a Creep Test.)

The stakes in building construction — and the costs of building-related litigation — are too high to think you can rest easy with the lowest bidder for concrete testing. You’re far better off with a tester who has a trusted, proven track record.

Testing results must be monitored over time

It’s important to keep tracking the test data throughout the project.

“When monitored continuously, test data is your early warning system for monitoring the construction process,” said Kenneth Hover, civil engineering professor at Cornell University, in an article for Concrete Construction magazine. “That information allows you to spot trends and make changes before the concrete goes out of compliance with the specifications, or exceeds the specification limits to the point that the mix should be adjusted.”

Choosing the best partner for concrete testing

Sloppy or imprecise testing might not have serious short-term repercussions, but if it misses flaws in the concrete mix that endanger buildings and the people who work in them, the liabilities can be staggering.

At CTL, we make a point of ensuring our concrete-testing experts are fully trained and certified according to the highest industry standards. We also ensure our testing equipment remains properly calibrated for precise, accurate measurements.

That’s the kind of dedication, professionalism, and experience required to build safety into concrete construction.