At Cor-Tuf, we are always looking for ways to test and maximize the characteristics of our proprietary Ultra-High Performance Concrete (UHPC). We have already shown through previous tests the amazing strength and durability benefits of this new concrete technology. We have also shown the advantages of Cor-Tuf UHPC over other conventional UHPC concrete mixes.
In our latest round of testing, we looked at the flexural strength of H-pilings made from Cor-Tuf UHPC. We looked at this across a “primary axis” where the central support of the “H” shape is oriented vertically and again across a “secondary axis” where the central support is oriented horizontally. The testing took place in Tallahassee, Florida, with the Florida Department of Transportation (FDOT). We are excited and proud to share the results with you here, as they show tremendous promise for significant cost benefits for future concrete construction projects using this new concrete product.
Cor-Tuf UHPC H-piling test results
All testing was done on 30′′x30′′x30′ Cor-Tuf UHPC H-pilings. These pilings are the first of their kind. This shape and size of UHPC piling had not been poured and tested prior, making this an exciting venture for our team. (It’s worth noting that these pilings are precursors to a larger 140′ version that we are in the process of getting ready to pour.)
Pictured above is a wide-angle shot showing the entire setup of the testing process in the Tallahassee testing lab. This press is designed to test the large structural components.
The unique design of the H-piling delivers many benefits over a solid square piling:
- Less material requirements due to the notches in the design
- Less internal components (pre-tensioned strands)
- Increased strength
- Cheaper to build due to fewer material requirements
- Lighter in weight
- Easier to drive as less soil is displaced
In other words, you get all of the functionality of solid square pilings, but at a reduced cost. H-pilings are also better-suited for more use cases than square pilings. Ideal use cases include:
- Marine applications
- Walls (including portable walls)
- Cast-in-place situations
- Prefabricated panel support
In our first part of testing, we tested the primary axis of the H-piling, which runs in a vertical direction. During this round of testing, we stopped periodically to gauge the product at various pressure stages. This is evident in the results graph below by the small dips in the graph line.
In our primary axis testing, we achieved 250,000 pounds of pressure. The product deflected 2.27 inches, which refers to movement of the concrete. As you will see, the deflection is lower than it is at the secondary axis. This is because the primary axis is more rigid.
In the second part of testing, we turned our attention to the secondary axis, which runs horizontally. In this round, we only stopped once to check the product and then let it go to failure.
As you can see from the photos, the stress cracks start at the bottom and work their way up. The break is contained. There is no ancillary cracking for several feet from the pressure point, as is typical with traditional concrete.
The peak load reached along the secondary axis was 205,000 pounds per square inch (psi) of pressure. The deflection at peak load was just under 4 inches.
While these pilings are a bit larger than the square piling we tested, the results are still quite impressive when compared to the square shape. Given the added benefits and the reduced cost, we are moving towards the H-piling design for our future concrete projects. We are confident this design will make UHPC H-pilings a better choice and a smarter investment for the future.
Stay tuned in the coming weeks and months for additional results from this and other testing. In particular, be on the lookout for a video trailer highlighting the 140′ UHPC H-piling we are getting ready to pour, as well as video footage of the testing discussed in this post and on the larger 140′ piling. We are excited to share these results with you as they become available.