Faster Bridge Construction with SmartUp UHPC

“Since we no longer have that delay in getting the product from France, it provides us the ability to deliver on projects rapidly,” says Robert Taylor, head of Business Development and U.S. Sales for National Cement. “So, the improved logistics have made a great product even better.”

National Cement Technical Service Engineer Hannah Tzabari spent much of 2023 working at Kirkpatrick Concrete’s lab in Birmingham going through the meticulous process of testing the product – locating a silica fume provider, evaluating sand, etc. – before actual production began earlier this year.

“It involved sourcing different options for our raw materials, and then some pretty rigorous testing to determine which raw materials are high-quality and consistent enough for us to produce the UHPC,” Tzabari says. “It took a lot of small-batching – and a lot of broken cubes and cylinders – to get it dialed in to being a product we are confident in using.

“Plus, the mixing process is a little different. We needed more energy to get it fully mixed into the fluid stage. So (National Cement invested in) a customized high-shear mixer, which really helped.”

The time and expense will be well worth it because, in the end, SmartUp UHPC will reduce the time and expense of bridge construction and replacement projects. One recent example is the company’s work over the summer with the Georgia Department of Transportation. GDOT replaced an aging structure in East Dublin, which originally was built in 1932.

“East Dublin was a joint-closure pour type of project, which is the most popular application we see with UHPC,” Tzabari says. “They used pre-cast beams and deck panels, and placed those on top of each other to form the skeleton of a bridge. Then we poured the UHPC into the joints in between these pieces, basically gluing all those pre-cast pieces together and forming the final shape of the bridge.

“This enables bridges to be replaced faster and more efficiently than the traditional bridge-construction timeline, and that has numerous benefits. Roads can be closed and reopened in a lot shorter timeframe, so it’s lower impact on the traveling public. It also tends to save costs because of fewer days on site.”

There is a long-term benefit as well in terms of durability. Taylor points out that the compressive strength of a SmartUp UHPC bridge is more than 20,000 psi, which is approximately seven times greater than the average concrete slab for a house. As a result, Taylor says these new bridges can have a lifespan of up to 100 years with minimal maintenance.

“It’s taken some significant advances in technology for us to get to these high strengths,” Taylor says. “Concrete has always been good in compression but poor in tension. With the addition of steel fibers to the mix, UHPC now delivers concrete that is also good in tension. This is a highly dense material, making it pretty much impermeable to chemicals and salts.”

“This product has really caught the attention of a lot of DOTs around the country. There are some distinct advantages that it gives us, and we’ve just scratched the surface of how it can be used. The product is in its infancy, but the potential and value of it are amazing.”