Jason Kilgore, the former owner of Kilgore Paving and Maintenance, LLC will run Harper-Kilgore, LLC post-closing with support from a strong management team across the combined operations.

Tom Hill, CEO of Summit, says that Utah is an attractive business environment and “is pleased to form our third regional platform in Salt Lake City through these acquisitions. Harper-Kilgore comprises many skilled and experienced employees and we would like to welcome them all into the Summit group of companies.”

Kilgore says the two companies complement each other well. “This marks a significant and exciting development for Harper and Kilgore,” he says in a prepared statement. ”The combined employee groups bring many skills and synergies to the new Harper-Kilgore company. We look forward to building upon our existing strengths to further improve our products and services for our customers and community.”

The new AEM Geospatial Industry Group is the result of a request from members of the Geomatics Industry Association of America (GIAA) to affiliate with AEM rather than operate as a separate organization. GIAA members looked at various industry associations and chose AEM because of its broad range of services and high levels of customer service.

GIAA had operated a statistical-reporting program for product sales in the Western Hemisphere, and this will continue under AEM, with plans to expand coverage and number of participants for added value. The new AEM Geospatial Industry Group’s initial focus will also include regulatory, standards and specifications issues as well as growing the membership.

“AEM product groups help manufacturers focus on business planning and development needs. This is an opportunity to use AEM’s extensive services to assist the geospatial industry reach more markets,” stated Paul Malek, AEM’s director of membership.

The current federal highway/transit investment law, SAFETEA-LU, expired nearly a year ago on Sept. 30, 2009. It has been operating under a series of short-term extensions, the latest through Dec. 31, 2010.

The federal government is the source of nearly 45 percent of all public capital investments in surface transportation.

The two organizations have developed campaign advertising to appeal to the general public with signs asking, “Sick of Aging Roads?—Tell Congress to Act!”

Similar messages have been developed for traffic congestion, transit delays and unsafe bridges.

Billboard advertisements have been running in South Dakota and South Carolina, and will also be posted in Illinois, Michigan, Tennessee, Iowa and Maryland beginning during the congressional recess in August and running through September.

As part of the campaign, Rep. James Clyburn (D-S.C.) held a news conference with coalition partners in Columbia, S.C., to mark the ad campaign’s launch in that state.

The ads direct viewers to the Website www.fasterbettersafer.org, where an action kit, instructions for contacting members of Congress, educational videos and other materials about the highway/transit bill are available.

The TCC, co-chaired by the American Road & Transportation Builders Association (ARTBA) and the Associated General Contractors (AGC) of America, is comprised of 29 national construction groups and labor unions with a direct market stake in federal transportation programs.

The ATM is a nationwide effort by business, labor, transportation organizations and concerned citizens to advocate for increased federal investment in the nation’s aging and overburdened transportation system.

A respective list of members of each coalition is available at www.transportationconstructioncoalition.org and http://www.fasterbettersafer.org.

This was a 15-percent decrease from the 2,436,000 permit tons recorded in July and a 14-percent decrease from the July preliminary imports total of 2,415,000 NT.

Import permit tonnage for finished steel in August was 1,623,000 NT, down 10 percent from the preliminary imports total of 1,797,000 NT in July.

August total and finished steel import permit tons would annualize at 24,305,000 NT and 18,912,000 NT, up 49 percent and 33 percent, respectively, from the 16,215,000 NT and 14,179,000 NT imported in 2009.

According to a draft copy of the five workshop presentations, CARB is saying they overestimated excavator activity by 61 percent and dozer activity by 60 percent. They’ve also concluded the load factors used in their emission estimates should be reduced by 33 percent. In fact, almost everything in its emission estimates — equipment population, activity, load factor, growth and inventory — is lower than originally forecast, CARB says.

But it’s too early to declare a victory, says Davis. The CARB staff says it needs additional time to “evaluate and explore appropriate regulatory proposals and consider their economic impact on affected stakeholders, determine the effect of any changes on emissions over the next decade and determine how to best protect public health in light of the health impacts of fine particle pollution (PM2.5) currently underway.”

 ”This means two things,” Davis says. “They won’t be ready for the November 18 (CARB) board meeting, so any changes in the rule will come in December or perhaps next year. Second, they still don’t have the science to justify these rules from a public health standpoint, so they hope to piggyback on new federal … regulations that will roll out soon.”

The Cool Hard Hat is a revolutionary pantented air-cooled hard hat developed by Tom English, a general contractor for over 30 years. English claims than in all of his years and experience in construction, The Cool Hard Hat is the best tool he has ever used and couldn’t imagine having to work without it. The rechargeabe batteries (with the recharger built into hat) power two fans to blow air on the of the neck and top of the head at a rate of over 8 cubic feet of air per minute. This lowers the interior temperature of the hard hat by more than 20 degrees. Watch the Video on the Company’s website to see the incredible cooling demonstration. The natural evaporation cooling process helps workers stay cool, fight fatigue and increase productivity. Vented hard hats are now obsolete as the popular cooling option. The hat can run up to 12 hours per charge of the batteries and can be recharged overnight.

The Cool Hard Hat meets all OSHA  and ANSI standards and is Intrinsically Safe.

The LSC portable light tower features a compact platform for jobsite mobility as well as truckload maximization with eleven fully-assembled units on a standard flatbed for cost-effective transportation. The LSC also utilizes up to 20 percent less space during storage and full operational deployment on a jobsite compared to the industry average, while maintaining its wind stability, static roll threshold and 30-foot extension capabilities.

Four 1,000-watt metal-halide floodlights provide a NEMA 6 x 7 beam spread for better light distribution and area coverage. The fixture design with a side-mounted/horizontally positioned bulb in each rectangular floodlight provides broad light distribution of 460 foot-candles. Cast-aluminum fixture housings include a separate reflector that lowers the risk of disruptive light distribution and offers a robust light. The small footprint of the floodlights reduces wind load.

The heavy-duty galvanized steel tower of the LSC extends from 12 to 30 feet and the mast is raised by dual, hand-operated winches and an automatic safety brake. Curly cord protection within the steel shroud along the first section of the tower prevents pinch or puncture damage. At full mast and with all four outrigger/jacks secured, the unit will withstand winds up to 65 mph. The telescoping tower can be rotated 360 degrees and locked into position for precise aiming of floodlights. For traveling and storage, a patented system automatically locks the tower into place when in the horizontal position.

The LSC light tower is equipped with a Mitsubishi L3E 1,800-rpm water-cooled Tier 4 Final engine. The engine, along with a 4.5 kW generator and 27 gallon fuel tank, provides up to

52 hours of continuous operation. The new light tower is backed by an industry-leading factory warranty providing 2-year/2,000-hour bumper-to-bumper coverage.

Superior strength and robustness for towing and operation stability is provided by a 7-gauge steel frame with integrated towbar. Safe towing of the LSC light tower is also ensured with a standard 2-inch ball hitch and a DOT full-running light package. All critical wiring is extended to the drawbar to enable easy hook-up to the tow vehicle. The trailer is also equipped with four tie-downs, zinc-coated chains, a license plate holder with light and VIN number for towing safety and compliance.

Options available for the LSC include dual electric winches with an automatic safety stop, a low fuel shutdown with indicator light and a block heater. Two optional hitches are also available — a combination hitch with a 2 ½-inch pintle eye and a 2-inch ball or a hitch with a 3-inch pintle eye.

By John Latta

The “donor” or “donee” debate still ignites controversy when it comes to the Highway Trust Fund. Did your state ‘donate” (give more in fuel and other highway user taxes and fees) to Washington than it got back, or did you state get back more than it gave?

The big and rich states have complained that they are subsidizing other states to the detriment of their own roads, and Senator Kay Bailey Hutchison (R-Tex) has pushed legislation to allow states to opt out of the HTF.

But a new study by the Government Accountability Office (GAO) shows that nearly all states have gotten back at least as much money from the HTF as they contributed since 2005.

Ironically, the lone exception was Texas which received slightly less than a dollar – 99.7 cents – for every dollar its highway users paid into the system. Other states’ returns per dollar ranged from $1.02 for Arizona to $5.63 for D.C. Of the remaining states, only Alaska at $4.92 topped the $4 mark and five states received between $2 and $3 for every dollar of input.

“In addition, all states, including Texas, received more funding than their highway users’ contributed during both fiscal years 2007 and 2008,” said the report. “In effect, almost every state was a donee state during the first fours years of the current transportation law “(SAFEYTEA-LU).

This was possible because more funding was authorized and apportioned than was collected from the states. The reference is to the almost $30 billion of general revenue channeled to the HTF by Congress since 2008 as the fund staved off bankruptcy largely because more funding was authorized than collected.

Current transportation law includes an equity bonus designed to guarantee states a minimum return. The Equity Bonus Program was used to address rate-of-return issues. It guaranteed about $44 billion. Nearly all states received Equity Bonus funding and about half received a significant increase, at least 25 percent, over their core funding. In effect, the bonus balances donor/donee status by disproportionately using the fund to lift donor states up to equity.

If the percentage of funds states contributed to the total is compared with the percentage of funds states received (i.e., relative share), then 28 states received a relatively lower share and 22 states received a relatively higher share than they contributed. Thus, depending on the method of calculation, the same state can appear to be either a donor or donee state, said the report.

But the report also highlights some of the problems that come with general fund infusions and with the requirement that the HTF be tied to a rate of return.

The report notes that the infusion of general revenues into the Highway Trust Fund affects the relationship between funding and contributions. “Using rate of return as a major factor in determining highway funding poses challenges to introducing a performance and accountability orientation into the highway program; rate-of-return calculations in effect override other considerations to yield a largely predetermined outcome – that of returning revenues to their state of origin. Because of these and other challenges, funding surface transportation programs remains on GAO’s High-Risk list.”

The report bluntly highlights a problem: “Adding general revenues into the trust fund and other challenges raise questions about relying on states’ rate-of-return to distribute federal highway funds.”

In addition to outside (general fund) funding, the report identifies two other wild cards that influence the amount and percentage of funds received: One is “the challenge of factoring performance and accountability for results into transportation investment decisions;” and two is “the long-term sustainability of existing mechanisms and the challenges associated with developing new approaches to funding the nation’s transportation system.”

The key to the problem is not hard to find; in fact, the report states it quite succinctly: “… the infusion of significant amounts of general revenues into the Highway Trust Fund Highway Account breaks the link between highway taxes and highway funding.” This is the problem that is worrying lobbyists and associations pushing hard for reauthorization. They fear that if an infusion from the general fund comes to be considered a common practice, then opponents of the HTF will claim the need for it has passed.

There is another problem: “The infusion of a significant amount of general fund revenues complicates rate-of-return analysis because the current method of calculating contributions does not account for states’ general revenue contributions. For many states, the share of Highway Trust Fund contributions and general revenue contributions are different, therefore state-based contributions to all the funding in the Trust Fund are no longer clear.”

The rate-of-return formula poses yet another problem when it comes to trying to factor performance and accountability into transportation investment decisions.

Incorporating performance and accountability for results into transportation funding decisions is critical to improving results. However the current approach presents challenges. Says the report, “…incorporating performance and accountability for results into transportation funding decisions is critical to improving results. However the current approach presents challenges. The Federal-Aid Highway program, in particular, distributes funding through a complicated process in which the underlying data and factors are ultimately not meaningful because they are overridden by other provisions designed to yield a largely predetermined outcome – that of returning revenues to their state of origin.”

In other words, trying to meet the rate of return criteria leaves little or no room to allow for performance and accountability factors. The Washington complaint as the GAO sees it in this report is that once the money is out of their hands they have previous little control over when, where and how it is spent.

So, how do you change that?

Well, the GAO says it’s trying: “For three highway programs that were designed to meet national and regional transportation priorities, we have recommended that Congress consider a competitive, criteria-based process for distributing federal funds.”

The report notes that with, “many surface transportation programs, goals are numerous and conflicting, and the federal role in achieving the goals is not clear. Many of these programs have no relationship to the performance of either the transportation system or of the grantees receiving federal funds, and do not use the best tools and approaches to ensure effective investment decisions.”

Performance and accountability for results must be considered in transportation funding standards. But according to the GAO, the need to return revenues to their state of origin overwhelms that process.

In the end, the report recognizes the inevitable: “A fund that relies on increasing the use of motor fuels to remain solvent might not be compatible with the strategies that may be required to address these challenges.” This of course raised a sequential question: If not the HTF, what? The GAO argues that in the near future policy discussions will need to consider what the most adequate and appropriate transportation financing systems will be and “whether or not the current system continues to make sense.” v

Let’s Treat Infrastructure Maintenance Like Debt Service (DIGITAL EXTRA)

By Eugene W. Harper, Jr.

THE BOND BUYER (www.bondbuyer.com)

We decry the decrepit state of our “crumbling” infrastructure, but we have yet to adopt legal rules needed to provide for its ongoing maintenance and repair.

A glance at the law governing enforcement of municipal bond obligations suggests a possible strategy for solving the maintenance problem, one that could be developed by state and local officials, bond lawyers, and other financial professionals.

Despite the drift of political and editorial rhetoric, the solution here is probably not to increase federal spending. Rather, it probably lies in the more tedious exercise of changing state and local finance laws nationwide to give maintenance spending the same priority, the same legal protection from political plunder, as debt service. This, even though maintenance spending is usually considered part of the annual operating budget separate and distinct from payments to bondholders.

Typically, bondholders are a “permanent” minority. In James Madison’s terms, they are a “faction” of lenders, always outnumbered by the (debtor) faction of voters. If bondholders had to rely for payment on the annual budget log-roll, they would, like any other permanent minority, almost always lose. They would need constitutional safeguards or other effective protection. Indeed, it’s precisely the existence of constitutional protection — or in some cases, an equivalently sturdy economic incentive — that permits states and localities to attract long-term lenders to finance capital projects.

Throughout the late 19th and most of the 20th centuries, bondholders relied largely on the non-impairment provision of the contract clause of the Constitution (and similar interpretations of state constitutions) for protection of their interests. Courts would generally enforce debt-service payment obligations against states and localities, even in the face of periodic political decisions to the contrary.

In the late 19th century, for instance, the docket of the U.S. Supreme Court was crowded with municipal bond enforcement cases. And not too long ago, in 1977, the contract clause protected covenants barring mass transit spending by the Port Authority of New York and New Jersey in the U. S. Trust case.

For more than a century, legal enforceability induced lenders to bear political risks that could result not only in payment default but also in a covenant breach. The muni bond market flourished and grew.

More recently, as shown by the explosive growth of “subject-to-appropriation” or “back-door” credits — where a legal obligation to pay arises only after an appropriation has been made in the fiscal period when payment is due — bondholders have come to rely on the expected draconian consequences of “repudiation” by a (sovereign) state.

If a state should fail to appropriate debt service for an authorized subject-to-appropriation credit, then, for all practical purposes, the market would consider that to be a repudiation of the state’s own debt. As a result, the state would lose access to credit markets, at least until the repudiation itself was repudiated by full payment. Loss of access is an altogether unacceptable risk, one imposing essentially the same payment discipline as legal enforceability.

For locals, markets generally don’t accept repudiation risk as an effective safeguard for long-term lending, in part because locals are in no relevant sense sovereign in our federal system, and in part because no one can confidently predict what they may do. After all, Los Angeles is now boycotting Arizona, and the West 67th Street Block Association in New York City once had its own foreign policy.

Those factors raise two questions about infrastructure maintenance:

Are supporters of current maintenance those who oppose “deferred maintenance,” a permanent minority in need of constitutional protection in our political system, just like bondholders themselves?

Are special projects like limited-access highways and toll bridges — which produce cash revenue to pay bondholders and where that cash is not normally required to be spent only in the budget appropriation process — in a different analytical position from ordinary infrastructure projects like local roads, bridges, schools, and parks, which produce no cash revenue and where general obligation or other tax-supported bondholders get paid even if the project falls apart?

As to the first question, deferred maintenance is hardly a laudable public-policy goal, despite the pledge of one desperate candidate to be the veritable champion of deferred maintenance. Rather, deferred maintenance is to be avoided if all that crumbling infrastructure is to be avoided.

No one can tell when maintenance is deferred, without granular expertise in capital and operating budgets. As a result, the repudiation risk has no bite. Everyone wants infrastructure to be maintained, but everyone also has multiple higher priorities. No special interest groups or political action committees organize around pro-maintenance slogans. Indeed, interest groups frequently target funds otherwise earmarked for maintenance as a funding source for their own wages, benefits, or transfer payments. Also, few ribbon-cutting photo-ops are held to herald maintenance programs.

So, yes, proponents of current maintenance and opponents of deferred maintenance constitute a permanent minority in need of constitutional protection in the normal budget process.

For the second question, comparing how we finance revenue-generating projects with how we finance ordinary infrastructure suggests a fix. Revenue bond indentures effectively protect maintenance requirements as if they were debt-service requirements by building the former into coverage ratios for the latter. Investors fear projects that are not maintained will fail to generate the requisite revenue to pay debt service.

Generally, no money is released from the lien of a revenue bond indenture unless debt service is paid and operations and maintenance requirements are met. Enforceable covenants require issuers to raise tolls, fares or other charges sufficiently to meet both those requirements.

By contrast, GO and other tax-supported debt instruments are not generally issued with enforceable claims for current maintenance. Ordinary infrastructure projects produce returns in the form of public goods, not cash — public goods that benefit taxpayers, not bondholders. Those projects’ bonds are paid for by taxpayers, not direct users, and taxing and spending for payment are part of the annual budget process, where any pro-maintenance lobby is a perpetual minority.

So, yes, we should consider reconfiguring state and local finance laws, jurisdiction by jurisdiction, to provide the equivalent of debt service protection for maintenance requirements, by authorizing financing mechanisms for ordinary infrastructure that recognize enforceable claims for current maintenance and repair. This would entail authorizing a parallel structure to a revenue-bond financing structure.

The aim here would be for budget-makers to provide for maintenance spending, along with debt service spending, before recognizing other claims on annual revenue. A one-size-fits-all model or uniform law would probably not work for 50 states.

This is not to suggest that maintenance claims are more important than the compelling and competing claims of teachers, police, or sick children. It is, however, to suggest that maintenance claims — like the claims of bondholders — are unlikely ever to be met in the normal political process without structural fiscal safeguards. So, unless we change the rules of the game, we’ll probably have to live with our “crumbling” infrastructure.

Editor’s Note: Eugene W. Harper Jr., a retired New York bond lawyer, teaches infrastructure finance at the Baruch College, City University of New York, School of Public Affairs. This article ran originally in The Bond Buyer newspaper. Bond Buyer is a SourceMedia publication. SourceMedia is owned by Investcorp, which also owns Randall-Reilly, the parent company of Better Roads.

Field tests show that the Next Generation Concrete Surface is competitive with the quietest pavements available.

In the past decade or so, environmental noise has become a major issue in many parts of the world, including the United States. Stakeholders ranging from the general public to the roadbuilding industry have expressed concerns over highway noise. Recognizing that highways are a factor in urban noise, the concrete pavement industry set out to research and develop quieter pavements without compromising performance, durability, safety or other inherent benefits of concrete.

NGCS pavements have been placed with either a single-pass or double-pass operation by the grinder, and both work equally well.

In recent years, the concrete pavement industry has developed a Next Generation Concrete Surface (NGCS). With field tests indicating sound levels of 99 to 101 decibels, these diamond-ground surfaces are producing results that are very competitive with the quietest pavements available, says Larry Scofield, P.E., Director of Pavement Innovation for the American Concrete Pavement Association (ACPA).

Sound testing is conducted using the On Board Sound Intensity (OBSI) method, which allows assessments of acoustic performance of pavements over time. The method was developed by General Motors and introduced to the highway community by the California Department of Transportation. More about the NGCS follows:

The background

Research showed that much of the perceived problem with concrete pavement’s noise results from a pure tone, or “whine” that occurs when noise with a certain discrete frequency emanates from the tire/pavement interface. Almost always, those frequencies were set with concrete pavement by uniformly-spaced transverse tining.

In an effort to improve pavement safety, the FHWA in the late 1970s had mandated transverse tining, and many states complied. Then in 2005, FHWA dropped the requirement for transverse tining, and opened the door to other concrete pavement texture treatments. California, for example, had used longitudinal tining for more than 30 years and reported few if any problems with it.

Recognizing the worldwide interest in quiet pavements, in 2004 ACPA, with support from the cement industry, developed a program to research the noise characteristics of concrete pavements. A primary objective was the evaluation and development of a quieter concrete pavement surface. Also providing support for the program were the International Grooving and Grinding Association (IGGA) and several of its members.

Purdue University’s Ray W. Herrick Laboratories conducted the research using its Tire Pavement Test Apparatus (TPTA). The machine consists of a 38,000-pound, 12-foot-diameter drum that makes it possible to test numerous pavement textures and compositions in combination with various tire designs. Six curved test sections of pavement fit together to form a circle around the vertical edge of the drum. Two tires, mounted on opposite ends of a beam, are then rolled over the test samples while microphones and other sensors record data. The TPTA has been described as a “noise microscope” for tire-pavement noise. Tire speeds of up to 30 mph can be tested.

Scofield says the Purdue diamond grinding research was based on theories that the blade- and/or spacer-widths might be the keys to a more quiet pavement surface. But after evaluating the range of blade and spacer widths requested by the industry, Purdue reported that no unique relationship could be found between sound levels and spacer width, blade width and spacer/blade configuration. Instead, it appeared that the controlling variable – where sound was concerned – was the variability in the fin profile height resulting from the grinding process. The fins are the tiny vertical ridges that appear on a diamond-ground concrete surface.

Textures with low variability were quieter than textures with high variability. In conventional diamond grinding, the resulting fin variability is influenced by the blade/spacer configuration, the concrete mixture, aggregate type, pavement condition, equipment set-up and more. Because the fin variability occurs in the field, it is difficult to adjust in a laboratory setting. Researchers decided to grind a pavement smooth, then impart additional texture by grooving, which provided an exact fin profile that could be controlled and predicted.

An epiphany

A conventional diamond-ground surface produces texture in the upward or positive direction, while the texture tested at Purdue produces texture in the downward or negative direction. “The texture, which later was called the Next Generation Concrete Surface (NGCS), was desirable from the standpoint that it was more of a ‘manufactured surface’ and thus could be controlled as necessary on an experimental basis,” says Scofield.

The Next Generation Concrete Surface is competitive with the quietest pavements available.

“When these new textures were tested on the TPTA, they produced the quietest diamond ground surfaces,” Scofield says. “This was an epiphany in the research because it verified, for the first time, what the controlling factor was for tire-pavement noise generation of diamond-ground surfaces.

“The point of the NGCS surface is to limit positive or upward texture,” Scofield explains. “The NGCS texture is designed to develop good macro-texture through ‘negative’ or downward texture (grooves). We want to have both good microtexture (the texture on top of the lands), and good macrotexture, which is developed primarily through the grooves.

“The NGCS is quieter because it relies on negative texture and not positive texture,” Scofield continues. “Since it is more of a manufactured surface, it can control the fin profile to a greater degree than previously possible. Purdue University determined that the fin profile is the critical element in noise generation.”

A new reality

The epiphany in research was soon confronted by reality, Scofield says. Research showed that the flush-ground-then-grooved texture could produce a quieter pavement. But the research could not verify whether such a texture could be constructed with conventional equipment in the field.

Next, in response to industry representatives, researchers developed two methods of reproducing the NGCS. The first was a grinding head configuration that used three smaller blades stacked between two taller blades. That pattern was repeated across the grinding head. That way, in one pass the head could grind the surface smooth and also groove it on approximately ½-inch centers in one pass of the machine. The smaller blades would flush grind the specimen and provide microtexture while the taller blades created grooves.

The second grinding configuration used the same smaller blades to flush grind the pavement in one pass. Next a second pass using taller blades with spacers created the grooves, similar to what was constructed with the single-pass operation.

That way, contractors could choose either option – the single pass or the double pass – in field construction. Some industry representatives thought the single-pass operation would cause excessive blade wear and have the potential for ruining the head and blades. Many believed the two-stage process would be required. Today, this is not a concern. NGCS pavements have been placed with a single-pass or double-pass operation, and both work equally well.

Field trials

The opportunity to construct field test sections became a reality when the Minnesota DOT allowed construction of test sections at the MnROAD Low Volume Road Test Cell Number 37 as part of an FHWA pooled fund effort. The two Purdue surfaces were to be compared to a conventional diamond grinding surface to assist in determining the benefit achieved by controlling the fin profile. So, there was a need to build three test surfaces.

This first-pass, flush-ground surface on I-355 in the Chicago area shows up as the whiter strip on the pavement.

Findings validated that the newly-developed surface was quieter, at the time of construction, than the conventional diamond ground texture. And, findings showed that the Purdue TPTA results could be reproduced in the field using conventional equipment. But because those were not full-width text sections, the next step was to construct a full-width test section using a conventional diamond grinding machine.

The first opportunity to construct a full lane-width test section occurred on Interstate 355 in the Chicago area. In October 2007, both a conventional diamond-ground test section and an NGCS were built on the I-355 tollway. The sections were 1,200 feet long and one lane wide.

Scott Eilken is the owner of Quality Saw and Seal, the diamond grinding contractor for the NGCS section at I-355. He is an ACPA member, a board member of IGGA, and was instrumental in writing the specifications for NGCS.

“On I-355 we did one pass to flush grind the surface, and the second pass as surface grooving,” Eilken recalls. “When we first tested it, the surface produced just 99 dB(A). We were one of the first concrete pavements in the nation to get below 100 dB(A), so it worked pretty well.”

The next opportunity to build test sections occurred at MnROAD’s Interstate 94. A two-lane wide by 500-foot-long section of NGCS was constructed in a single-pass operation on a 14-year-old random transverse-tined pavement in October 2007.

With the successful placement and performance of the two mainline sections, the ACPA officially named the texture as the Next Generation Concrete Surface (NGCS). The name describes a category of textures that evolve for both new construction and rehabilitation of existing surfaces.

“The desirable characteristics of such textures will be predominately negative texture coupled with good microtexture and excellent macrotexture,” says Scofield. NCGS can now be found at seven sites in five states. There are three test sections near MnROAD; one in suburban Chicago; one in Norman Okla.; one near Abilene, Kansas; and one near Omro, Wis.

Other test sections have been established this year in Washington state and in Arizona.

All surfaces are still performing as intended. As of 2009, ACPA’s figures show that OBSI testing was conducted on 288 pavement sections consisting of 126,720 lineal feet (24 miles) of concrete pavements across North America. The surfaces were evaluated with two goals in mind; first, to benchmark current surface texturing practices, and second, to develop insight into the acoustic longevity of textures. The acoustic longevity will become increasingly important as quiet pavement technology becomes integrated into noise mitigation.

Recent sound results from the MnROAD test sections indicate that NGCS pavements are running in the range of 99 dB(A) to 101 dB(A). By comparison, conventional diamond ground sections ranged up to 104 dB(A).

One test section in Kansas shows that an NGCS surfaces has produced 99 dB(A) and 100 dB(A) in two different tests. By comparison, an Astro-Turf drag surface ranges up to 102.5 dB(A) and an exposed aggregate surface ranges up to 104.5 dB(A).

A renewable surface

At MnROAD, Diamond Surface Inc. constructed a surface casually called NGCS LITE, which was designed as a renewable surface. It was developed to provide additional microtexture on existing NGCS surfaces if the need arose to do so. With the large land size (between the grooves) of the NGCS surface, the texture wear has been assumed to be less than for a conventional diamond-ground surface. So, NGCS is expected to have a long life by comparison. v

by Daniel C. Brown, Contributing Editor

In association with ACPA

(American Concrete Pavement Association)

How the Mechanistic-Empirical Pavement Design Guide Helps Optimize Concrete Pavements

The M-E PDG can account for numerous variables in concrete pavement design

In its simplest terms, concrete pavement design optimization considers the performance benefits of various components versus their cost.

Design optimization can be thought of in various ways, says Michael Ayers, PhD, Director of Education for Design and Construction at the American Concrete Pavement Association (ACPA). Those include:

Achieving long life;

Lowering initial cost;

Minimizing maintenance and rehabilitation costs; and

Developing a sustainable, environmentally-sound pavement system.

Until recently, pavement designers were mostly limited to the 1993 AASHTO Pavement Design Procedure. Although many agencies are still using the 1993 protocol, it has limited inputs and is not ideal for optimizing pavement design.

Concrete pavement design optimization considers the performance benefits of various components versus their cost.

By contrast, the current AASHTO Interim Mechanistic-Empirical Pavement Design Guide (M-E PDG) has many more input parameters, which allow designers greater influence over pavement performance. The M-E PDG combines empirical or observed pavement performance data from a number of sources – primarily the Long-Term Pavement Performance Studies done under the Strategic Highway Research Program, and mechanistically-calculated pavement response parameters.

“When you combine those two elements, it gives you the flexibility to account for various types of design optimization,” says Ayers. The variables to be considered depend on the design method used in the analysis. The M-E PDG has the capacity to consider support conditions (including subbases for concrete pavement), concrete materials and properties, load transfer (both longitudinal and transverse), and numerous other criteria.

ACPA provides training programs in which designs are generated using the AASHTO 1993 guide, M-E PDG and StreetPave software, and are optimized for performance. Ayers says slab thickness is often used as a basis for comparison between design elements. However, says Ayers, it is preferable to compare estimated costs for the overall pavement structure including the subbase, load transfer, slab configuration, etc.

To establish a baseline design using AASHTO 1993, Ayers established the following inputs for an example:

Traffic: 20 million 18-kip rigid Equivalent Single Axle Loadings

Reliability: 90 percent

Concrete Modulus of Rupture: 600 psi

Concrete Modulus of Elasticity: 4.050 million psi

Load transfer coefficient: 3.2

Drainage coefficient: 1.0

Initial serviceability: 4.5

Terminal Serviceability: 2.5

Initial and final serviceability reflect the initial construction quality (primarily smoothness) and the end of the design life of the roadway (the point at which major rehabilitation or reconstruction is required).

With those inputs, AASHTO 1993 produces a calculated slab thickness of 11.5 inches. With AASHTO 1993, concrete strength and load transfer are important parameters. However, specific guidance as to the configuration of load transfer is not provided. Concrete durability and dimensional stability issues are also not addressed.

Many important design elements cannot be accounted for using AASHTO 1993. Simply altering traffic levels, reliability, support conditions, and levels of serviceability is not a true design optimization strategy, Ayers says.

Inside the M-E PDG

In 2008, the M-E PDG was adopted as an Interim Design Procedure by AASHTO. Full implementation by the states will take a number of years, and some states may not adopt it. The “final” version of the program, referred to as DARWin ME, is currently under development. However, the research grade software is available as a free download at (http://trb.org/mepdg/home.htm).

Ideally, optimization should be conducted based on a state or regional calibration of the M-E PDG. State or regional calibrations take into account such factors as climate and locally available materials.

The bases for comparison among the various design features are the three failure criteria for concrete pavements in the M-E PDG. The three criteria include transverse slab cracking, joint faulting and smoothness as determined by the International Roughness Index (IRI).

In his example of how M-E PDG works, Ayers includes the following variables:

Concrete strength;

Coefficient of thermal expansion of the concrete;

Subbase type and thickness;

Dowel bar size;

Edge support; and

Joint spacing.

30-year design

Failure criteria was set to the default values for cracking, faulting and IRI. Slab cracking was set at 15 percent; a faulting threshold of 0.12 inches was used; and terminal IRI was set at 172 inches per mile.

Those values, Ayers emphasizes, can have a significant effect on your final design. Establishing realistic failure values for a specific project is a key to successful use of the M-E PDG software.

Two primary climatic zones were analyzed in the example: Wet/freeze in Chicago, Illinois; and dry/no freeze in Phoenix, Arizona. Traffic was based on 5,000 AADT, and M-E PDG default values were used for traffic variables. Fully 100 percent of the design traffic was allocated to the design lane. The compound annual growth rate was fixed at 2 percent, and the design period was 30 years.

Next, Ayers chose suitable values for: soil type; granular subbases; concrete properties (modulus of rupture and coefficient of thermal expansion); dowel bar diameters and spacing according to ACPA guidelines; and edge support. A number of pavement configurations were evaluated, including the following: a 12-foot lane with no shoulder; a 13-foot widened lane; a 14-foot widened lane, and a tied concrete shoulder.

Graphs were developed illustrating the climatic effects on estimated transverse cracking, estimated faulting, and estimated IRI. In each case, the independent variable is shown as the slab thickness, and the failure mode is plotted as the dependent variable.

Similarly, the effects of base type on estimated transverse cracking, faulting, and IRI were plotted for various base types. Again, the independent variable is the slab thickness and the failure mode is shown on the vertical axis. For example, at a slab thickness of 10 inches, using a granular base in Chicago with 50-percent reliability, cracked slabs go to zero.

The effects of various modulus of rupture values, coefficients of thermal expansion, dowel diameters and spacing, and edge support were plotted to show what happens to the various failure modes for varying slab thicknesses.

Ayers says the next steps are to establish unit costs for the most likely design elements such as dowels, widened lane, treated versus untreated subbase type, and so forth. Designs that meet specified criteria – specifications, design standards for the type of pavement structure being constructed, materials availability, etc. – are selected. An economic analysis is then conducted to select the “best” designs. The final step is to select the least-cost, best-performing option, and rerun the analysis on the selected design for verification.

The results

In Ayers’ trial runs of the ME-PDG, design thicknesses ranging from 8 inches to 12 inches met the established criteria depending on the design elements selected. An economic analysis would determine the optimal design elements to specify in the final design. For instance, the use of a 13-foot widened lane significantly improved performance and thereby lowered the required slab thickness. The economic analysis would then determine if the added cost of the widened lane was offset by the decrease in slab thickness and difference in anticipated performance. A similar analysis would be performed for each critical design element. The process can become somewhat complex when multiple variables are analyzed simultaneously, according to Ayers.

Conclusions

Design optimization can lead to cost savings and enhanced performance if correctly applied. In order to generate realistic design options, a relatively sophisticated design procedure such as the ME-PDG should be used. Although it is possible to generate comparable designs with the AASHTO 93 Guide, the limited number of variables and sensitivities make comparing options difficult.

Implementation of the ME-PDG is an important step in developing realistic comparisons between design options.v

by Daniel C. Brown, Contributing Editor

In association with ACPA

(American Concrete Pavement Association)

jlatta@rrpub.com

Politics, ah politics. You can smell it.

Members of Congress, or least the vast majority of them, won’t consider a higher fuel tax to fund a new surface transportation bill. Without it, any bill would be inadequate.

But what about after the election?

The President’s 18-member bi-partisan Deficit Commission set up in February is to deliver its recommendations by December 1, a few weeks after the polls close. We will have a new Congress and perhaps a new majority party, at least in the Senate. Some dismiss the commission with faint praise, but the word deficit might be a game changer. It will be a massive issue for Congress whoever has won.

Quite recently politicians have had Eureka! moments and discovered fuel taxes can be raised without making then look bad. You use them for deficit reduction AND roads.

It happened in 1990 and again in 1993. Under President George H. W. Bush the gas tax was upped by five cents, half of that amount going to the HTF and half to deficit reduction. President Bill Clinton raised the gas tax another 4.3 cents, all of it for deficit reduction. The deficit’s 2.5 cents from the Bush administration was legislatively re-directed to HTF in October 1995. In 1997, Congress redirected Clinton’s 4.3 cents to the HTF.

One advantage of this approach is that the user fee principle (those who use the roads pay for them with taxes used only for roads) remains enshrined. The potential loss of that link seriously worries industry groups. Another advantage is that the final formula is not set in stone, allowing a lot of horse trading and posturing. How much is raised and how it is distributed and when all or some of it reverts to the HTF is open to debate. Of course that can also lead to gridlock, and possibly, as the industry would fear, possibly too little funding in the deal for the HTF. Oh, and the deficit is being attacked.

This is still not the simplest answer. That comes from another president. Ronald Reagan initially said no to raising the fuel tax, just as Barack Obama has done. But he was convinced otherwise by the inherent common sense of the non-deficit raising ‘user pays’ model, evidence that willingness to change one’s mind in public can be a political strength. Reagan raised the gas tax – without using the deficit option – a nickel in 1983 because, “The cost to the average motorist will be small, but the benefit to our transportation system will be immense.” He meant jobs, safety, less congestion and a stronger infrastructure. In other words, déjà vu all over again.

The Reagan model is needed. Period. But, if politics is the art of the possible …v