How do you test in-place concrete?
The most common concrete inspection activities include testing the properties of fresh (wet) concrete and casting cylindrical specimens for strength testing, but these cannot directly verify the integrity of the concrete that makes up your structure. This is particularly problematic when dealing with large or inaccessible projects, such as drilled shafts for deep foundations.

One service that FTG offers is Cross-hole Sonic Logging (CSL). When a shaft is poured, it is installed with a series of hollow tubes around the perimeter. Once the concrete has hardened, we are able to lower probes throughout the depth of the shaft. Through a sonic pulse sent from one probe to the other, we can directly measure the properties of the concrete at any depth/cross-section to ensure design specifications are met.

What do you do if a flaw is detected in the concrete?
We recently performed CSL testing on a shaft along Route 7 and found some areas of concern. Specifically, it appeared that there was a noticeable fluctuation in density about 10 feet below the surface. Although shaft remediation is one of our specialties, we elected first to take cores from this area for closer inspection. Upon receiving the cores at our lab, it was visually apparent that the CSL test had picked up on a variation in the air content of the concrete. Luckily, as opposed to an intrusion or some other defect, variable air content is not necessarily a problem. We cut specimens from above, below, and through the areas with this variation and tested them for density and compressive strength. Ultimately, we were able to show that the concrete in question had reached an appropriate strength for the load it would carry, and therefore no remediation would be necessary.

With CSL and other non-destructive test methods, our team can provide that extra factor of assurance that the work that's been done meets the necessary standards of safety and function. In the event that a problem is detected, our first priority is always an efficient response, followed by determining the nature and extent of the problem with little impact to the structure while also offering effective solutions at minimal cost and delay.

Visit our services page to learn more about how FTG can keep you on track, under budget, and in spec at every phase of construction.