Behind the Screed

Reviving Rubber in Florida

“We had been hit with almost $51,000 in penalties on a job mandated to use rubber because the bottom kept dropping out of the mix,” says Tim Carter, quality control at P&S Paving based in Daytona Beach, Fla. “These AC content anomalies were just killing us. Until Evoflex® RMA turned things around.”

Such was the predicament of Carter’s team at P&S Paving in November of 2016. They found themselves paving an 11-mile stretch of State Road 19 in Putnam County near the Ocala National Forest. Almost an hour and a half from the mix plant, Carter’s team began the 16,000-ton job using an alternative PG 76-22 asphalt rubber binder (ARB) for the 12.5 mm friction course mix. But after multiple attempts to meet density requirements, Carter’s team needed an alternative solution.

Enter Ingevity’s Evoflex RMA, a hybrid pelletized additive for mixes that mandate the use of rubber. RMA is unique because it combines ground tire rubber (GTR), SBS polymer and Ingevity additives into an easy-to-use-pellet. Evoflex RMA allows the use of existing plant blending equipment; consistently produces on-spec binders; and comes with the world-class technical support that customers expect from Ingevity.

“Many contractors think it’s extremely difficult to achieve density with a stiff binder containing rubber,” says Lance Brooks, technical marketing manager at Ingevity. “That’s just not true. This project was an hour and a half haul; was paved in cool November and December ambient temperatures; and had a PG 76-22 hybrid ARB binder. The binder even sat in the tank for almost two months after being blended at the liquid supplier’s asphalt terminal.”

“The specification required 93% density,” reports Carter. “We achieved 93 to 94 percent throughout the mat. We have worked with Ingevity and know the great technical service we get from the team, so this made our choice to use RMA much easier. But even for contractors or asphalt suppliers unfamiliar with Ingevity’s products, these results speak for themselves.”

Crew members on the job remarked about how easily the mix went down using the standard rolling pattern and were surprised to have such workable material with the stiff PG grade and rubber added.

“The Evoflex was a game changer,” shares Carter. “We went from scratching our heads and getting hit with penalties pre-Evoflex RMA, to celebrating and winning a bonus after we began using it. We made back almost all of our losses with RMA.”

Click here to learn more about Evoflex RMA or contact [email protected].

Warming Up The Inauguration

For over 200 years, the presidential procession and inaugural parade have marked the beginning of the new U.S. Commander in Chief’s term in office. Although the majesty of the procession and swearing-in ceremony garner most of the attention, the behind-the-scenes preparations for an event of such grandeur cannot be overlooked. Beginning months prior to the January 20th celebration, the parade route must undergo significant construction and beautification projects. It is here that Ingevity’s Evotherm® is making some history of its own.

As part of the infrastructure improvements leading up to the event, the blacktop along the parade route gets a facelift. The already-plunging temperatures in Washington, D.C. in late October are a large consideration when paving. For the second inauguration in a row, Evotherm warm mix asphalt technology was selected as the preferred technology.

Ryan Bragg, field and applications engineer, explains: “Usually the Washington D.C. Department of Transportation releases the bid for this project last minute and it typically becomes a rush to finish before the cold weather sets in. The contractor in charge was looking for a product that would help with compaction and workability in the cold weather because they would be paving a very thin lift (only 1-¼ inches) in 40 degree temperatures at night.” Traditionally, a lift this thin will experience rapid heat loss from both the surface it is being placed on, as well as the colder outside air. By using Evotherm, the contractor ensured a longer window for the crews to achieve required compaction numbers on this job during the last week in October.

“It is both humbling and flattering that Ingevity’s technologies continue to be the go-to choice for high profile projects. It’s a great testament to what our team has accomplished with Evotherm,” says Jonathan MacIver, business director. “Contractors in the D.C. area look to our warm mix technology when they must be able to meet compaction and workability requirements despite the cold weather.”

How can Evotherm bring some warmth to your next project? 

Fiberless For The Future

At about this time every year, bright minds at the New Jersey division of Tilcon New York, Inc., based in Wharton, are contemplating the coming year. The Tilcon team has devoted a great deal of time and energy in becoming a regional leader that develops the newest technologies from their Mount Hope laboratory facility, which are then verified by the New Jersey Department of Transportation. One such technology involving Ingevity’s Evotherm® WMA technology in a fiberless stone matrix asphalt (SMA) mix was used in early summer of 2016 on Route 80 in N.J.

Aleksandra Rogozinski, Quality Control Supervisor with Tilcon in Wharton, N.J., explains: “At the end of 2015, our technicians in the lab, Peter Truncale and Brian Dailey, were experimenting with a winter design using no fibers. In the past, we had traditionally used SMA with fibers. Our team was evaluating a fiberless mix mainly because the fibers and filler are costly.” While still above the NJDOT minimum requirement of 6% liquid AC, Tilcon’s new design decreased the filler content by nearly two percent and the asphalt cement (AC) content by 0.4 percent - significantly reducing the cost of the mix.  Aleksandra continues: “There were concerns about whether the mix would hold together. But what we found is that this fiberless mix performed similarly to the traditional SMA.”

SMA’s commonly use polymer-modified asphalt at elevated loadings.  The production and placement temperatures needed to successfully place a conventional SMA project can result in asphalt drain down and fat spots in the pavement.  Fibers are used to reduce this problem. Using Evotherm WMA technology, Tilcon is able to reduce their production and placement temperatures. The reduced temperature enabled by using Evotherm results in a higher binder viscosity. The higher binder viscosity is less prone to drain down.  In fact, if one can reduce the temperatures enough, fibers can be eliminated entirely.  

To date, Tilcon is enjoying many benefits of their new fiberless mix. “The Evotherm allows us to reduce the temperature of the mix,” reports Aleksandra. “Using a 64E—22 liquid, we saw production temperatures as low as 295ºF, compared to a standard production temperature of 325ºF, and compaction temperatures as low as 250ºF in the lab. These lower temperatures reduce our energy costs.” Additionally, Tilcon is seeing improvements in compaction. With a greater compaction window, they can use fewer rollers on the job because there’s more time to work with the mix as it is placed.

“The contractor on the Route 80 job was originally hesitant to use this mix,” explains Aleksandra. “But after seeing these kinds of results, they’ve committed to no longer use traditional SMA. Their product of choice is a fiberless mix using Evotherm.”

What does your fiberless mix of the future look like?

A Facelift For Florida

What do three years, nine phases, $40 million, 266 centerline miles and "good for the environment" have in common? That would be the City of North Port’s massive pavement resurfacing program designed to address the needs of this growing area in Florida.

North Port is located one-half hour southeast of Sarasota, one hour south of Tampa and only 20 minutes from the scenic Gulf of Mexico. Despite its prime location and beautiful weather, the city’s roadway infrastructure was not so beautiful prior to 2014. In fact, its roadway system was failing. Matt LaChance, technical marketing at Ingevity, explains: “The city had ignored their infrastructure for many years before realizing that much of their 800 mile network was on the verge of failure. North Port leaders chose to bond $46 million to reconstruct or resurface 266 miles of selected roadways across the city so that the road network matched the beautiful scenery.”

Once the bond passed, the city had to ensure that the money was well spent. This is when engineering consulting firms HDR and VHB were brought on board to develop a specification and bid documents, as well as manage the projects and the public works staff. During the specification development phase, the consultants suggested that the city require the use of warm mix asphalt (WMA) to be both ecologically responsible and to gain greater road life by lowering temperatures. In order to ensure the lowest temperatures possible, the specification called for a chemical additive from the approved product list of the Florida Department of Transportation (FDOT). Matt explains: “Because the specification also called for the use of a liquid anti strip, Ingevity’s Evotherm® WMA technology was the natural choice for Ajax Paving, one of the asphalt producers that won bids.”

Ajax embarked upon what would become a much-needed facelift for the city’s roads: a 100,000 mix ton county—residential overhaul using Evotherm. Ajax produced a PG 58—28, 40% RAP, 9.5 mm surface mix terminally blended with Evotherm. The project began at 7:30 a.m. when the ambient temperature was in the mid 70s, quickly increasing to 93ºF. Mix was produced at 275ºF with minimal temperature loss over the 30-minute haul.

Rusty Reynolds of Ajax is emphatic that “the ability to produce this type of mix at 275ºF and achieve consistent density, texture and aesthetics during a 30-minute haul with minimal temperature loss is outstanding. This was a reality because we used Evotherm.”

The result of Team Ajax—North Port is an outstanding roadway that’s a testament to both partner’s openness to innovation and their tireless commitment to the environment.