At Cor-Tuf, we’ve been using classic ready-mix techniques with our Ultra-High Performance Concrete (UHPC) for some time. One of our latest projects was completing a ready-mix bridge overlay job in upstate New York to demonstrate how easy UHPC is as part of everyday construction.
Bridge overlays are a top layer of concrete material that restores a bridge’s structural integrity. UHPC is emerging as a preferred approach to bridge overlays because of its long-term strength and its contaminant-resisting properties that protect the rebar and other components of the bridge deck. Even a thin layer of UHPC can add decades of safety and performance benefits to old bridges.
Our recent Cor-Tuf UHPC overlay project in Addison, New York was smooth and simple. We provided bags of material and mobile admixture pumps to a typical dry-cast plant. The fibers, Cor-Tuf mix, and admixture were combined with local sand, cement, and water in a common ready-mix truck. The bridge was about 40 minutes down the road. Onsite, the crew easily poured the mix, which was spread and leveled with typical hand tools and a hand-cranked truss screed.
The key to this successful overlay project was nothing extraordinary, which is exactly the point. Contractors in the field used local materials and traditional techniques, resulting in a low-cost approach that benefits from the long-term superiority of UHPC. This group of contractors is a local outfit from small-town America, proving that UHPC is not only for niche markets or university research projects, as was the case 25 years ago.
Local Materials and Machines
Most concrete plants have achieved economies of scale by building relationships with material suppliers. They also already have machines and tools for mixing, pouring, leveling, and finishing concrete to high standards. Thousands of normal concrete jobs are completed, on time and with certainty, relying on straightforward orders with dependable sourcing. Supply options close to home or from nearby construction hubs are essential to efficient construction.
To take advantage of the pricing and logistical benefits that come with local materials, UHPC needs to be compatible and easy to mix with a variety of locally sourced components. There should be no need for extra logististical planning, boutique small-batch ordering, or imports from the other side of the country (or the world!). Small-town crews and large city firms alike understand the headaches that come with experimental installation requirements.
Let’s consider the typical UHPC on the market. It requires specialized mix ingredients, in addition to specially procured sand, cement, and fancy machinery, alongside a roster of specialists who must be onsite to scrutinize procedures throughout the process. The specialists set up a contraption with multiple mixers and a specialized machine to produce a highly sensitive chemical mix resembling concrete. The placement machinery may require assembly onsite by other specialists, who charge a premium by the hour. It is not unexpected when something goes wrong, because these specialized systems are prone to hiccups arising from small deviations from standard test conditions. Construction crews experience delays if they aren’t working in perfect site conditions or if they miss a single unusual detail.
Now consider the alternative, captured in our videos. Our recent UHPC overlay was done with a regular road crew using a standard ready-mix truck. It involved hand tools, easy mobile batching, and was not much different than a typical driveway job. There were no fancy machines from Europe or white lab coats jotting down every movement while administering a list of “extras.” We all know who foots the bill for those, which is why we sought a solution that scraps the unnecessary imports and works with local construction.
The only requirement for Cor-Tuf UHPC is our bag product and admixture. It can work in any batch plant or mobile mixing operation, and regardless of the admixture your plant already uses. Using automated controls and an extra silo for bulk material, any casting facility may be used to achieve our UHPC. It’s an easy, familiar process that works into existing operations.
Keeping Costs in Check
If you think we’re cutting corners or hiding prices, you’re welcome to watch us work on real projects. The craziest thing you’ll see is that you can’t even tell that our product is different by observing the installation. If you’re driving by, it appears to be another concrete pour on any bridge or foundation. For this project in New York, the mixing process process was quick and easy as well: some bags were cut open into the drum, the truck was filled with cement, water was added, the admixtures and fibers were included, and the truck was on its way.
Many contractors feel priced out of the UHPC market. By enabling flexibility and eliminating the demands of most UHPC product procedural specifications, we have drastically cut the cost of UHPC. Speed of installation, workability of the material, compatibility with ready-mix are a few synergies we’ve established, to open this market up to more concrete suppliers in competitive situations.
Our approach is to advise if you need it, but not to step on your toes. We don’t just sell you something and say, “Good luck!” Our UHPC comes with support and technical resources, especially for the first couple of mixes. Beyond that it’s up to you how involved you want us to be. We don’t need to be on site looking over your shoulder, unless you request it. Constant oversight has been a typical requirement for most UHPC providers, driving up the cost to pay for every inspector. By making our UHPC seamless and easy, the burden on contractors has decreased, along with the costs of implementation.
Let’s also consider some typical challenges that can disrupt cost expectations with ready-mix. Most UHPC providers who claim to be ready-mix-compatible fail to mention their actual experience. They often doctor the usual process or compromise a piece of equipment, such as the mixing drum. Does their mix allow for typical cleaning and continued use of the drum? Unfortunately, the residue from most other UHPC mixes results in a layer of permanent residue, too caked-on to be cleaned properly for use on another job. The drum can’t be salvaged and must be retired, resulting in another hidden cost and another procurement challenge.
Contrast this to Cor-Tuf UHPC. After a successful UHPC overlay job, we simply wash out the drum with some coarse gravel and regular water, and it’s clean and back in rotation.
Cor-Tuf UHPC—For Overlays and Beyond
UHPC is here to stay. We know how to realize the benefits of strong, durable, water-resistant UHPC without upending the process or costs associated with concrete installation. Our recent overlay project is another example of how classic ready-mix techniques can harness our mix products with ease and efficiency. The key is keeping it simple with labor, equipment, overhead, and materials. Your sand, your cement, our Cor-Tuf UHPC.
Image Credit: https://beeldbank.rws.nl, Rijkswaterstaat
