Unique ABG Screed Delivers High Performance – And a Trophy

Winning a prestigious industry award requires more than meeting specifications. It demands careful planning, proven processes, an experienced crew and the right equipment. 

“The best contractors don’t just meet the standards – they go beyond them,” said Thomas Wilson of Andale Construction, based in Wichita, Kansas. “Every project presents unique challenges that must be met head-on.” 

Andale did exactly that while placing more than 1 million square feet of Roller Compacted Concrete (RCC) in 22 days on the Embarcadero Gateway Building jobsite in Laredo, Texas. The project included unique geotechnical challenges, which Andale overcame with the help of an innovative developer, Farias Development, LTD., and the geo-technical expertise of Howland Engineering and Surveying Co. Inc. The team was one of the first to use RCC in Laredo, Texas.  

The efforts paid off, as the group earned the Gold designation in the RCC (industrial/commercial) category of the American Concrete Pavement Association (ACPA) Excellence in Concrete Pavement Awards. ACPA, founded nearly six decades ago, is a federation of contractors, cement materials manufacturers, equipment manufacturers/distributors, and other industry stakeholders who act as the voice of the concrete paving industry.  

Andale found a distinct advantage in using an ABG 8820 paver equipped with a high-compaction VDT-V 89 double-tamper vario screed – a patented design unique to Ammann’s ABG products. 

Why Pre-Compaction Matters 

RCC behaves more like aggregate base than plastic concrete, making early mechanical energy critical. A tamper screed provides that energy. “It delivers immediate, deep compaction and reduces the number of roller passes required,” Wilson said. 

ABG developed the double-tamper screed to provide even more pre-compaction and a high-quality surface. 

“With a double-tamper, the material is compacted twice before the screed leaves it behind,” Wilson said. “We’re achieving up to 98% pre-compaction, and the ABG screed is the reason why. We tested competitive systems and didn’t find another paver and screed combination that could consistently reach that density while paving a 6-inch to 10-inch mat.” 

How Double-Tamper Technology Works 

Double-tamper screeds strike the material twice before it reaches the baseplates, delivering 5% to 7% higher pre-compaction than single-tamper designs. Achieving up to 98% density behind the screed significantly reduces roller passes, fuel use, emissions, equipment wear – all while improving smoothness and overall quality. 

The first tamper redistributes material and begins compacting the mat. The second enhances density and uniformity. By the time the material reaches the baseplates, it is already compacted and leveled. The baseplates provide the finished, smooth mat surface. 

This technology has proven effective for asphalt courses, granular materials, RCC and cement-bound materials – especially in applications where traditional compaction is difficult. 

On The Jobsite 

On the Laredo jobsite, density up to 98% was registered on the 7-3/4”-thick RCC mat before rollers even hit the material. The paver was followed by a 10-ton roller. 

Pre-compaction by the unique ABG double-tamper system eliminates passes of the roller – the number varies from one job to the next – which lowers costs and minimizes the potential for surface damage. On average, the ABG paver reduces a minimum of two paver passes when compared to the other available pavers with “high-density screeds,” Wilson said. The paver is able to place extremely thick lifts because the pre-compaction provides such deep density. 

On some jobs, the high level of pre-compaction has allowed Andale to use smaller, more cost-effective rollers instead of larger models. 

Smoothness and Joints 

Achieving smoothness when placing RCC is a unique process. With asphalt, there are multiple lifts of mix – and multiple opportunities to iron out bumps. RCC offers only one opportunity, in the form of a single thick pass, which makes subgrade preparation and pre-compaction crucial. 

RCC has zero slump and historically wasn’t finished. Modern RCC is troweled and finished with a broom. Andale prefers to use ACEiT Industries Blue as a finishing aid when troweling before applying the broom finish. 

Andale utilizes ACEiT Industries SF-200 additives in the RCC mix when fresh-joint paving. The additive delays mix set times and improves workability, compaction and finishing. For construction joints, Andale over-paves by 6” and later saw-cuts a new edge – a practice Wilson calls “cheap insurance” to ensure structural integrity.  

Joint work is made significantly easier with the VDT-V 89 screed, which features a variable width and an advanced crown profile screed that will break 10º +/- in the wings. 

“It’s the Cadillac of screeds,” Wilson said. 

Cost Savings Are Common With RCC When Compared to Conventional Concrete 

Andale is a pioneer in modern RCC, having offered the application for more than 15 years. 

“When we first started placing RCC, most customers hadn’t heard of it,” Wilson said. “We had to offer warranties to convince them to try it. When we had the opportunity to pave a project for a customer, we made sure to place a quality product – no matter what. In this industry your reputation is everything. Most of our customers are repeat customers.” 

In those early years, and even to this day, price is what often convinces the customer to consider RCC. “The lower cost gets their attention, and then we have an opportunity to educate,” Wilson said. 

Wilson said RCC is usually more affordable due to: 

• Lower overall material expenses 

• Reduced labor through the use of a paver instead of traditional concrete placement equipment  

• No rebar requirements 

• Faster curing and tighter schedules 

The savings add up. “The use of RCC on the (award-winning) Laredo project resulted in savings of 10-17% compared to traditional concrete construction,” Wilson said. “Cost savings are common, and on large projects it can reach millions.” 

Specialized Concrete Plants Required For RCC 

“RCC can’t be made in your normal dry-batch concrete plant down the street,” Wilson said. “Because it’s such a dry mix, RCC requires a pugmill to efficiently mix at the production rates required for placement.” 

Mike Conley of Ammann sees the RCC market as poised for growth. “We value our partnership with Andale Construction and the Roller Compacted Concrete Pavement Council,” said Conley, Director of Sales & Distribution Development at Ammann America. “Together, we’re advancing RCC use and applications. The ABG paver and double-tamper screed have delivered outstanding performance, and we’re proud to support the industry leaders putting this technology to work.” 

Resources 

Ammann America and Andale Construction are both active members of the Roller Compacted Concrete Pavement Council (RCCPC). To learn more about RCC, visit https://rccpavementcouncil.org/. 

For information on RCC additives and finishing aids mentioned in this story, contact ACEiT Industries at https://www.aceitusa.com/.