Concrete strength testing, while still relevant, isn’t the most ideal option for traffic openings – especially if it is a highly traveled highway.
It requires fabrication of the concrete samples near the slab, demolding, curing the samples on site until 24 hours prior to testing the specimen, transporting them demolded and then place in a water bath for 24 hours. Along with taking far longer than other methods, traditional strength testing also poses a wider margin of error. Enter concrete maturity testing.
Concrete maturity testing is a streamlined way for QA/QC experts to test for compressive and flexural strength. By placing maturity sensors within the concrete, data can be collected rapidly through electronic devices using an application, eliminating the need to drive between the lab and the project site. The team at G3 Quality has used concrete maturity sensors for multiple projects around California and is one of the first to assist our clients in the Golden State.
Learn more about why maturity testing may prove more efficient than strength testing when it comes to traffic openings.
Concrete Strength Testing Caveats
Concrete strength testing involves taking a sample of freshly poured concrete, allowing it to cure under controlled conditions, and then bringing it to failure. The results are then compared to project requirements to determine whether the concrete is strong enough for use in construction. If the failure is higher than the requirement, the sample material is approved for use.
However, concrete strength testing has its roster of challenges. Specimens need to be fabricated and cured properly for accurate results, and temperature fluctuations during curing can affect material strength. Transporting specimens from the job site to the lab may also risk micro-cracking and false readings, not to mention human error, such as failing to follow protocol and mistakenly damaging material samples.
“When it comes to strength testing, there are a number of risks and margins of error to be aware of. Micro-cracking can result in a false reading, for example. Human error is likely the biggest issue though. You can do everything as diligently as possible, but samples can still be damaged if certain protocols aren’t closely followed.”
- Marc Robert, Technical Services Director, G3 Quality
This can cause significant delays in traffic openings, which is unacceptable if it’s a particularly busy road or highway. Thankfully, there’s a more streamlined method that’s especially helpful for urgent traffic openings: concrete maturity testing.
Why Concrete Maturity Testing Is Best for Traffic Openings
Concrete maturity testing removes many of the uncertainties of strength testing, including those margins for error. It can be used for any high-strength concrete application, from high-rise buildings and bridge decks to other structures that require accurate compressive or flexural strength readings.
Sensors are initially installed in the concrete pour, typically the body of the sensor is about two inches below the surface with the cable place approximately half the depth of the concrete member. The sensors measure the heat of hydration, which correlates directly to concrete strength. Once in place, testers can use their electronic devices with an application to quickly measure the maturity compressive concrete strength. Agencies such as Caltrans are now offering the use of maturity sensors to determine whether early-stage materials can be used.
By comparing the maturity reading from the sensors to a predetermined strength vs. maturity curve, compressive or flexural strength can be accurately predicted – and once a sample reaches that maturity level, it’s ready for use in construction.
As opposed to strength testing, concrete maturity testing doesn’t require specimens to be molded, transported, or directly tested. The concrete cures undisturbed, while strength is measured electronically. This provides rapid, reliable results right on site versus constant trips between the lab and job site, making it a more convenient option for urgent traffic openings.
G3 Quality’s Concrete Expertise
As one of the labs in California that’s completed four different projects using sensor technology, G3 Quality is a local leader in concrete maturity testing.
We’re one of the few firms that have implemented sensors for concrete maturity for multiple projects throughout the state, helping clients gather and interpret the data they need to keep projects on track. It makes for a far more streamlined process when compared to strength testing, and while sensors were mostly useful for only compressive strength, G3 Quality is now using them to measure the flexural strength of concrete materials.
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