An increased emphasis at the federal level on portland cement concrete (PCC) durability will help make concrete last even longer in abusive environments. Driving this is the fortuitous move of so-called high-performance concrete (HPC) application out of structural elements only and into pavements, a process underway at the Federal Highway Administration's Office of Technology Applications. 

Improvements to equipment are making placement of concrete 
pavements, intersections and ultrathin whitetoppings easier and more 
competitive with asphalt. In fact, yesterday's "fast-track" concrete paving -- a revolutionary concept in which PCC pavements are placed and cured in a time span competitive with asphalt -- has been so well-incorporated into mainstream PCC paving that it's rarely spoken of by itself anymore. 

And to top it off, the American Concrete Pavement Association (ACPA) has welcomed as its new president, Val Riva, whose tenures at the National Stone Association (NSA), Associated General Contractors (AGC) and American Road & Transportation Builders Association (ARTBA) will bring a strong national focus to PCC issues, promotion, and "Inside the Beltway" lobbying. 

Riva's presence will reinforce the Washington work of vice 
president/government affairs Ted Ferragut, P.E., whose appointment earlier in the decade began ACPA's move from being a regional group to one truly national in scope. 

But PCC still suffers from a substantial cost disadvantage compared to asphalt, a gap PCC proponents say doesn't exist when long-term maintenance savings are considered. The medium still is perceived as being rougher and noisier than asphalt, problems which are being addressed by stricter paving standards. 
 

HPC in pavements

With its HPC initiative -- described in detail at ACPA's annual meeting in December -- FHWA has articulated its goal of providing the public with safe, smooth, quiet, long-lasting, environmentally sound and cost-effective concrete pavements. These are: 

• To permit design, construction and maintenance of economical PCC pavements for high-volume traffic routes, incorporating a 35- to 50-year lifetime, vs. the current 20-year design
• To develop cost-effective concrete alternatives for low-volume roads, and
• To develop appropriate and effective maintenance and rehab strategies for PCC pavements.

In the last three years FHWA has sponsored a number of projects 
evaluating certain features of HPC pavements. "These projects are under various stages of design and construction," Vanikar said. 
"As we build them we will have vast experience available that we can compile for a major technology transfer activity." 

Most of these projects will be built this year, with a few for 1999. States with HPC paving projects include Iowa, Wisconsin and Kansas. "We are hopeful that we will have funds available to continue these projects in the future," Vanikar said. 
 

Capturing market share

But to truly expand market share, PCC will have to capture more of the rehab dollar than it has now. The ultrathin PCC overlays being constructed across the country are demonstrating that agencies don't automatically have to use asphalt for overlays. 

And in terms of life span, concrete is far better suited for reconstruction than asphalt, proponents say. This will be a major promotional thrust for the industry in the years to come. 

"In the past for reconstruction or rehabilitation, we have put down one product," said ACPA's Ferragut. "But if we continue to do this same type of reconstruction, we are forcing ourselves into an eight to 12-year rehabilitation program." 

The result will be endless reconstruction, Ferragut said. "You will have 10 to 14 percent of your system under reconstruction all the time." 

This equates to a significant waste of money for traffic control as 
pavements are unnecessarily overlaid with asphalt again and again, Ferragut said. "Traffic control costs 25 to 30 percent of a project, for the barrels and the people who move them. That's not 
infrastructure repair. That's not for physical replacement of the facility. We have to look at these costs." 
 

Contractor control

Like in asphalt, concrete contractors are finding themselves more 
responsible for pavement specifications, including mix design and quality control/quality assurance (QC/QA) procedures. 

The reconstruction with PCC of I-65 in Indianapolis -- which won the 1997 National Quality Initiative Award -- stipulated that the PCC pavement meet Indiana DOT's statewide QC/QA specifications. These specs permitted the contractor team of Berns Construction Co. and Weddle Brothers Construction Co. substantial flexibility in designing the concrete mix and establishing raw material parameters and tolerances. 

A quality plan was submitted that required the contractor team to 
demonstrate a thorough knowledge of the paving process by listing 

•  Experienced personnel
•  Laboratory facilities
•  Origin and material sampling methods
•  Traffic patterns for paving
•  Equipment capabilities
•  Production testing, and
•  Detailed PCC placement plan

Its full-depth concrete shoulders were utilized because of their value to longevity, and for future construction project which might shift traffic over to the shoulder area. 

Complaints with PCC roughness are being addressed as well, via field projects. The I-65 project met a mandated profilograph tolerance of 1.0 inch per 0.10 mile. 

Another recent, smooth project was an award-winning, 11-inch-thick, 
jointed concrete pavement over 4-inch bituminous base in Liberal, Kan. This project -- Pancake Blvd. -- was built by Wittwer Paving of Wichita, and met 4.0 inches per mile on a 0.2 blanking band, as measured by the California profilograph. 
 

Getting rid of 'chatter'

Equipment manufacturers are rising to the challenge of quickly placing PCC pavements of exceptional smoothness. 

"The stakes for the contractor are getting immensely higher, and the 
opportunities more dramatic," said Jim Mikulanec, national accounts manager, concrete paving products, CMI Corp. "There's an unlimited amount of opportunity." 

Ride quality is driving much of PCC placement equipment innovation, Mikulanec said. "The traveling public, even more than the highway departments, are demanding an ultimately smooth pavement," he said. "The contractor has to make the decisions to get improved ride." 

As a result, some states have gone to "zero blanking banding" on 
profilograph measurements. A 0.2-inch blanking band was part of the original California profilograph used to measure pavement smoothness, which allowed for surface irregularities in PCC pavements. 

Anything but a zero reading can mask pavement roughness, even though a pavement meets existing smoothness specs. But while it was good enough for contractors and state DOTs, it wasn't good enough for the traveling public, Mikulanec said. 

"Zero banding is a measurement of ride quality that takes away what the industry calls 'chatter', vibration felt in the car that is not measured roughness," Mikulanec said. "We're addressing it from the paving point of view." 

CMI's Hydramation leveling sensor control is a non-electric paver control system that assists operators in achieving ultrasmooth pavements. Beyond that, Mikulanec sees smoothness as being a "people problem" more than a construction or equipment problem. "There is at least a generation of skilled operators who are no longer on the job," he said. Like other manufacturers, CMI is addressing that problem through training courses and other outreach. 

"Many of our contractors are having trouble training people because the construction industry represents the entry level in a lot of markets," he said. One way to get around this is to make "smarter" machines. 

"One system that we are offering in this new construction season is a 
dowel bar inserter that will fit under our SF-6004 tractor in a paving configuration, with an oscillating beam and a correcting auger, full-profile pan and drive bars all within the wheel base of a standard four-track paver," Mikulanec said. This system has the ability to eliminate one machine and one operator, as well as several ground personnel. 

"With equipment, materials and contractors being involved, ridability is much improved," said Carl Carper, vice president, worldwide sales and marketing, GOMACO Corp.

"Equipment is being improved all the time," he said. "We're focusing on our new dowel bar inserter, a compact, quickly assembled product. The latest thing in concrete paving equipment is the ability to insert dowel bars automatically, in the right place." 

And down the road lie use of GPS systems in pavers, although they still lack the detailed tolerances for paver use. "We can locate a ship on the ocean to three feet," Carper said, "but we need to be within an 
eighth of an inch for paving." The technology isn't there yet. 

"The need for training is paramount," Carper said. As many as 700 
persons in a year will pass through GOMACO University, with 10 to 15 percent from outside the United States. 
 

Innovative applications

Iowa is upholding its reputation as a state where innovation takes place in PCC pavement design and placement. "Last October [1997] we had an open house in which we rubblized an existing concrete pavement and put a concrete overlay on top," said Gordon L. Smith, executive vice president of the Iowa Concrete Paving Association. 

"That's something the asphalt industry has been doing, but we wanted to see if we could alleviate some of the D-cracking we've seen due to aggregate expansion problems in Iowa," Smith said. "We found that with our unbonded overlays we've been getting a good 20 years of service, but we want to extend that service life by doing the rubblizing." 

A resonant breaker -- which shatters concrete using harmonic vibrations -- was used on a county road for that overlay. A nominal 6 inches of PCC -- one cement enhanced with GGBF slag, and another with calcined clay for durability and workability improvements -- was placed over the seated, rubblized base. 

Another project was scheduled for spring 1998, in which a multiple drop hammer may be used. ICPA also is researching via field trials -- in conjunction with the Iowa DOT and Iowa State University -- alternative products used for load transfer between slabs, including fiberglass and stainless steel dowel bars.