Cat^® SDX Screed Plate System Delivers Results

Accounting for approximately 65% of the contract’s $77.23-million value, major categories included some pavement removal, common excavation, borrow excavation, drainage piping, placement of an 18-inch aggregate base course for the new roadway, asphalt paving and topsoil placement. The project’s timeframe extended from April 1, 2023 through October 5, 2024, with a five-month winter work suspension from November 15, 2023 to April 15, 2024.

The contract specified placement of a 3.5-inch asphalt overlay on the existing two-lane roadway, while the new, two-lane segment involved placement of an 18-inch crushed stone base supporting 7.5 inches of new asphalt. Some segments were divided, and some were not. Pavement bonus payments were available for asphalt compaction density and IRI smoothness scores.

At the November 5, 2024 ribbon cutting, Chad Orn, NDDOT deputy director for planning, said, “The successful completion of this Highway 85 four-lane project is a major win for the state of North Dakota. This heavily traveled highway received several major upgrades that will increase safety for motorists and pedestrians, improve traffic flow, and enhance the movement of goods.”

In addition to the measured results, members of the Central Specialties paving team provided the following observations about the performance of the Cat SDX Screed Plate System.

“I’ve observed many asphalt-paving innovations during my 22 years in the business, and these Cat SDX Screed Plates rank right up there near the top of the most-impressive list,” noted paving superintendent John Fales. “We’ve been using them for more than a year now. When we first started, we quickly noticed the uncompacted mat behind the screed was much denser. When we walked on the uncompacted mat, we weren’t leaving footprints. That in itself was very impressive and convinced us this technology was for real.

“Over time, we also observed the metallurgy used in the SDX Screed Plates were helping them last much longer – six, seven, or eight times longer. That’s impressive, particularly when you consider that we’re dealing with very jagged, crushed granite and quartzite. With these drier aggregates we’re seeing here in North Dakota, we’ve also been able to run the pavers as fast as 90 feet per minute. Productivity is up. Smoothness is up. And density behind the screed is up. And compacted density across the mat is more consistent. What we’ve noticed the most is a denser, tighter wear surface, plus we’re not seeing nearly as much roller squish-out.

“The kneading action through and below the Cat SDX Screed Plates that the Cat Paving guys like to talk about really helps lay down a tighter, denser mat. The density behind the screed is consistently higher than we normally see with conventional screed plates. Squeezing out the voids definitely helps with increased quality in four key areas: density, smoothness, resistance to moisture penetration and wear surface longevity. We can lay an inch and a half-compacted mat containing three-quarter (inch) rock, and you’re not going to see segregation like you would with traditional plates. The screed plates might be eliminating as much as 95% of the segregation that we see on some jobs. The longer I’ve seen the new screed plate in action, the more impressed I’ve become with the results.

“When it comes to longevity, these SDX Screed Plates are really tough. In highly abrasive material, we’ve sometimes had to replace conventional plates at less than 50,000 tons. The SDX plates went 300,000 tons, and upon removal and replacement, we discovered we could have used them even longer with no impact on paving quality. The wear longevity has become a key selling point for us. All things considered, what’s not to like about the SDX Screed Plates?

“Plus, we always receive top-notch parts and service support from Ziegler Cat and from other Cat dealers when we’re working outside Minnesota. That’s a given and a key aspect of what separates Cat machines from other brands. Wherever we work across the upper Midwest and Plains states, Cat dealer support is always a positive. In our home state of Minnesota, Ziegler is particularly outstanding. We rely on them for parts, field service, shop service, rebuilds, trade-ins, equipment financing and more.”