Recycled rubber tires used in asphalt pavement mixes are not really new to the New Jersey Department of transportation. 

In fact, the agency had mile-long sections of I-195 and Route 9 laid with asphalt rubber open-graded friction course in 1994. The aim was to make a serious evaluation of the AR-OGFC pavement for possible future applications on New Jersey highways.

Originally, I-195 was built with a hot-mix asphalt pavement while Route 9 is Portland cement concrete. Both AR-OGFC overlay pavements’ longevity results have been impressive with them still in tact and structurally sound.

However, there is more to these AR-OGFC projects than their longevity as revealed by a comprehensive pavement/tire noise-level study. Both pavements demonstrated significant noise-attenuation when compared to other pavement types.

In 2004, the New Jersey Department of Transportation funded a study that was carried out by the Center for Advanced Infrastructure & Transportation, Rutgers University. Briefly, the study included documenting the pavement/tire noise levels on 42 different pavement types by using the National Center for Asphalt Technology Noise Trailer. The NCAT Noise Trailer is a sophisticated noise-level measuring device that is installed in its own custom-designed trailer. It isolates pavement/tire noise from extraneous noises and records the noise level expressed in decibels that are generated by the NCAT Noise Trailer tires as they ride over the pavement at highway speeds.

The results of the pavement/tire noise level pointed to the AR-OGFC pavement as the best of all pavement types in the study with a low of 96.2 dB recorded at a 60-miles-per-hour vehicle speed. The highest noise level (sound pressure) was recorded on I-78 at 106.7 dB where the pavement was PCC with transverse tining. However, route 29 and I-287 PCC sections that were diamond-ground PPC pavements had a significant reduction in sound pressure with 98.1 and 98.7 dB, respectively. Still, the AR-OGFC was a 25% decrease in the overall pavement/tire noise level.

The pavement types that were tested included 35 different HMA pavements (AR-OGFC, OFGC, Novachip, dense-graded asphalt, microsurfacing, SMA) and seven different PCC pavements.

The impressive noise-reduction results found with the AR-OGFC pavements in this study inspired NJDOT to resurface a significant section of I-95 with AR-OGFC. NJDOT was concerned about the pavement/tire noise levels being too high with the more traditional mix designs. 

The Research

Robert Sauber, chief pavement engineer for NJDOT, is leading the research and applications-development program on AR-OGFC. He allocates the NJDOT funds for original research projects (not only on AR-OGFC) that is carried out at CAIT, which costs NJDOT as much as $1.5 million per year. He also is an enthusiast for the use of AR-OGFC for he is convinced there is so much in its favor benefiting NJDOT and the people of New Jersey.

Actually, the I-95 resurfacing project, which was started and completed in 2007, originally called for the conventional HMA 12.5H76 surface course. Sauber saw this project ideal for AR-OGFC because the highway goes close to populated residential areas where noise pollution is of concern. “The time had come that we [NJDOT] were ready to take on a sizeable paving project using AR-OGFC paving based on the low sound pressure results found at I-195 and Route 9. With the AR-OGFC pavement, I knew we could minimize pavement/tire noise,” says Sauber. 

Progressive contractor

Fortunately, the contract for the project was held by one of the leading progressive contractors in central New Jersey, Trap Rock Industries. Trap Rock, headquartered in Kingston, enjoys success not only as a paving contractor but also as an aggregates producer and as an HMA producer. The company owns/operates four quarries and 10 HMA mixing plants that are strategically located in central New Jersey.

Sauber approached Trap Rock’s Wayne Byard, QC Technical Services and he also serves as the chairman for the New Jersey Asphalt Pavement Association’s Technical Committee. The principal owner of Trap Rock, William Stavola, approved the pavement-change idea. “Stavola was very enthusiastic about teaming up with NJDOT to ensure the project was a success,” says Byard. 

Project background

I-95 is the main north-south highway in the eastern United States going through Florida to Maine. New Jersey’s segment connects at the Pennsylvania border and heads northeast to New York City. Starting at the Delaware River, the 8-mile project includes three northbound and three southbound lanes. The resurfacing also includes the two 12-foot-wide outside and two 5-foot-wide inside shoulders. 

The winning bid was $19.2 million, which does not include the additional costs incurred from substituting the Superpave with the AR-OGFC paving. NJDOT and Trap Rock had a team spirit for both parties realized that close cooperation would ensure the project’s success. 

Paving equipment

To ensure high quality paving results on its paving projects, Trap Rock buys top equipment that can generate quality work. “We buy the paving equipment we feel is the best for the company in terms of quality results at the most economical cost.  Performance and the equipments’ reliability come first, so we bought three Roadtec pavers and one Roadtec Shuttle Buggy SB 2500 materials transfer vehicle. Our preferred brand of rollers is Caterpillar. We get good service from both makes of equipment and no problems with parts supplies,” says Dave Majoros, projects manager for Trap Rock.


A worker operates the controls of the RP-195 paver to be sure that materials used match the quality specified.

The equipment used for handling, laying, and rolling AR-OGFC for the most part can be of the traditional design. However, that said, there is one caveat that Trap Rock found to be a challenge. The crumb rubber/asphalt mix is exceptionally viscous and stickier than that found with standard asphalt. These properties cause some of the HMA to adhere to the delivery dump-truck bodies. Even adding a release agent to the boxes did not completely solve the problem.

A must in paving NJDOT highways is the use of the Roadtec Shuttle Buggy.  Spraying the tack coat in front of the paving train precludes the delivery trucks from being positioned in front of the paver for directly feeding the HMA. The Shuttle Buggy is driven in the adjunct parallel lane so the tack coat is not transferred to the Shuttle Buggy or dump truck tires.

Operating in the second lane is accomplished with swinging the Shuttle Buggy’s HMA feed conveyor. It is designed to swing right or left within a 110-degree arc, thus offsetting the Shuttle Buggy from the paver’s forward-moving alignment (i.e., the lane).

If a Shuttle Buggy were not to be in the paving train to avoid trucks running over the tack coat (on secondary roads), there is a special Roadtec SP-200 paver that can address the tack-coat issue. It features a 2,100-gallon tank that has a 500,000-Btu diesel-fired helical-coil recirculating heating system for maintaining the specified tack-coat application temperature. The tack coat is precision-sprayed onto the road immediately in front of the screed so delivery dump trucks’ tires do not come in contact with the tack coat. Likewise, if the Shuttle Buggy is in the train path, it too will not come in contact with the tack coat despite its same-lane position as the paver.

NJDOT now specifies that an MTV such as the Shuttle Buggy must be used on every highway-paving project, no matter what HMA is specified, hence including AR-OGFC. This mandate is to the paving contractor’s benefit. “We offer one of the highest paying smooth-ride bonuses in the country so the Shuttle Buggy should pay for itself. We also are one of the strictest on rideability standards that carry heavy fines when ride smoothness does not meet the standards. Fortunately, paving with AR-OGFC does not present any more rideability challenges than there is when resurfacing with Superpave,” says Sauber. 

I-95 project goes smoothly

The formal designation for the project is Route I-95 Resurfacing Contract No. 001033240. It called for milling the existing road 3-inches deep (402,000 surface yards). This procedure was carried out by a subcontractor using two milling machines making one pass. Following the milling, Trap Rock paved the road in three lifts. There was first the base course, which is NJDOT Superpave HMA 19H76 (19-mm aggregate). The 3-inch course required 73,993 tons of HMA. Next, a 2-inch lift of Superpave 12.5H76 (12.5-mm aggregate) intermediate course (84,196 tons) was laid followed with a 1-inch surface course of AR-OGFC (23,879 tons). 

Equipment enables quality production

There are two important elements if high-quality paving is to be assured, a first rate paving crew and good performing paving equipment. The Roadtec paver selected by Trap Rock for the project proved to be a very good choice, if quality results matter. It is the model RP-195 paver, one of three of the same in Trap Rock’s fleet. However, Trap Rock has four pavers. While the company prefers to have pavers by one brand, the fourth paver is the last of another brand that is currently being phased out of the fleet. With the company’s policy of purchasing equipment that is optimum for Trap Rock, Roadtec has been its preference since 2004.

The paver can handle AR-OGFC paving as easily as it does Superpave, according to Joe McAndrew, project supervisor. It features the wide rubber-track design for working in all types of paving projects, including tight areas.

Heading the paving operation is Chuck Samaritano, paving foreman, who is considered along with his crew as exceptional performers by the Trap Rock management. Paving on the project started at 9:00 p.m. (one hour after the paving lane and the access working lane were closed) when paving the north lanes and 10:00 p.m. (likewise, one hour after lane closings) when paving the south lanes. Correspondingly, the paving stopped at 4:00 a.m. (north) and 5:00 a.m. (south). The different closing/opening times were subject to the level of traffic activities.

With a seven-hour paving time permitted, the nightly production ranged from 1,800 to 2,000 tons of AR-OGFC or Superpave. That is 257 to 285 tons of paving laid each hour. The lay-down was continuous because of the Shuttle Buggy in the paving train.

There were three Caterpillar rollers used for rolling the AR-OGFC mat. Unlike compacting Superpave, each roller was set in the static mode (vibratory actions were turned off) and each roller made only one pass. The aim is to let the voids (about 14 to 16 %) remain in the pavement and not to compact, thus increasing its density. 

Looking to the Future

NJDOT envisions a significant future for HMA AR-OGFC on New Jersey highways. Its Commissioner, Kris Kolluri, emphasized in a recent press release that the I-95 AR-OGFC resurfacing project is both “eco-friendly [and a] quiet pavement.”

It is eco-friendly because it recycled 80,000 tires for paving a six-lane, 5-mile section of the project. NJDOT’s Chief Paving Engineer, Robert Sauber, says that New Jersey disposes of 44,000 used tires each day. That is plenty of rubber available for making plenty of AR-OGFC paving.

Besides eco-friendly and quiet, Kolluri lists other benefits associated with using AR-OGFC paving. It provides exceptional durability, good tire skid resistance, smooth ride quality, and improved visibility because it substantially reduces road glare caused by artificial or sun light.

Sauber adds to the list its favorable economics. Labor and paving costs are no higher than paving with Superpave. As for the I-95 project, replacing the Superpave with AR-OGFC added only $500,000 to the $20-million project. “That is peanuts when you take into consideration the pavement will last about 15 years. That is far more time than can be expected from any of the other paving types we use or have tested,” says Sauber.

Not only was the project finished within the original contract completion date but, also according to Sauber, Trap Rock accomplished a very smooth ride, so it will receive a six-figure rideability bonus. “We have been fortunate in teaming up with Trap Rock. They were willing to do whatever it took to ensure its success. They provided a good paving crew and good equipment to make it happen. By using the Roadtec Shuttle Buggy, the contractor got a smooth pavement,” says Sauber.

The beat for using AR-OGFC paving in New Jersey goes on. A new AR-OGFC paving project is being let out for bid in late January this year. It will be a six-lane by 7-mile section of I-280 that has a PCC pavement. Sauber says a shim course will first be laid (to smooth out its rough ride) followed by a one-in AR-OGFC course. A second major paving project will be let in January to resurface a section of I-78.