Making sure the numbers add up is the first step to a successful job

That mill-and-fill job up for bid may seem the exact boost your company needs right now.

The biggest benefit for milling contractors today is flexibility of machine application, says Wirtgen America Senior Vice President Jeff Wiley. “Every job is different,” he says, “and the operator today has the opportunity to select the type of grade control system he wants to use.”

It may very well be, says Terex Roadbuilding’s John West, but there’s work to do before – or even if – you submit.

“Priority number one for the milling contractor,” he says, “you have to know what that aggregate is, in order to be able to envision what it’s going to cost you in carbide consumables and what you can project your daily production numbers to be.” A milling machine has 200-250 carbide tools, valued at about $4 apiece, he explains. “Now, are you changing those hourly or are you changing them daily? That’s a $1,000 to $10,000 variance daily. You can bid yourself right out of business here, just depending on what the severity of the aggregate is. You want to know what you’re up against before you get up against it.

“Normally, you’ll spend more on carbide tools in three years of ownership than you pay for the machine itself. It’s nothing for a contractor to spend $200,000 or $250,000 seasonally on a milling machine, just on carbide tools alone. If you can decrease that annual cost by 10 to 15 percent, that’s a huge number, particularly if you run a fleet of 10, 12 or 15 machines.”

Milling or cold planing generates recyclable or reclaimed asphalt pavement (RAP), which in turn can be used as aggregate base, stabilized aggregate base, cold-mix asphalt or new hot-mix asphalt, says Eric Baker, marketing manager with equipment manufacturer Roadtec.

On the milling side, says West, also to be considered before bidding are requirements for smoothness and pattern increasingly obligated by agencies to be tested and approved as prerequisites for project completion and contractor payment.

This will lead directly to the contractor’s cost-variable cutter pattern requirement, determined by the number of carbide teeth placed on the milling machine’s mandrel. Roadtec’s Baker explains from coarse to fine:

Excavating Pattern provides coarse 3/4-inch spacing, allowing a significant increase in production. This technique of “strip milling” is used where full-depth removal, up to 12 inches, is desired.

Traditional Pattern, with grooves spaced 5/8th of an inch apart, is the industry standard for asphalt overlay. Suitable for milling up to 8 inches in depth, it allows production with an acceptable temporary driving surface.

Profiling Pattern, described as a fine-textured version of the traditional pattern, requires more teeth on the drum for reduced spacing of 3/8th of an inch. Best used on cuts no deeper than 2 inches, the result is a surface suitable for driving, with or without fresh asphalt overlay.

And Micro-Milling, sometimes referred to as “carbide grinding,” is performed prior to a seal coat to re-establish profile, grade and skid-resistance or to “de-slick” flushed pavements. The typical pattern of 1/5th of an inch is best used on thin cuts of no more than an inch deep.

A smooth milled surface with the correct profile provides two major benefits for paving contractors, Caterpillar Paving Products reported in a recent New Hampshire and Vermont case study: the crew would be able to pave both lifts using grade control on both sides of the paver, thus avoiding smoothness-losing profile built with slope control; and total smoothness improvement would not confined to just the leveling and wear courses.

“Milling contractors are entering an era now where the word ‘milling’ needs to be thought more of as ‘profiling,’” says West, Terex Roadbuilding product support specialist. “Regardless, you have to have weight, horsepower and grade control in order to maintain a productive balance. You just can’t take an undersized machine, place it on an oversized task, and expect a happy result.”

Half or Full

So, does this mean bigger is better? That depends on where you’re working, says West.

“Some jurisdictions, if you’re going to do mill-and-fill, will not accept half-lane cuts. You either cut the entire lane or you’re not going to not get the project.” This, he says, is often an agency’s reaction to past problems with contractors not being able to maintain cross-slope. One match between two lanes is easier to hold than mid-lane breaks.

Having said that, “there’s still merit” for a half-lane machine working on roadways squeezed between the need for rehab and the demand to keep traffic flowing, says West. “The motoring public does not have a problem with us giving them a smooth, new surface to drive on. They just don’t want you to get in their way while you do it,” he says. “If we ever find that magic formula to do both at once, we’re all going to be very rich and famous people.

“They’re asking us to do more work in less time in less space, basically.

An answer, among advice offered by roadbuilding equipment manufacturer Wirtgen America, lies in the contractor’s use of manpower. “It’s important that an owner keep his crew with a machine as long as he can,” recommends Jeff Wiley, senior vice president. “It’s not a good idea to send the crew back to the union hall at the end of the year, and get a new operator and crew the next year that has to be trained all over again on that machine. When crews stay on a machine month after month, year after year, they understand it; they know what to do on the machine to keep it up and running.

“The best crews are those that have been with the machine for the life of the machine.”

This approach works particularly well today, when cash-tightened agencies are increasingly looking to “near-term remedies” such as mill-and-fill, says West, closing in on 30 years with Terex Roadbuilding and its predecessor companies. “Our Rotomill did for the milling industry in the 1970s what our RS500 did for the reclamation/stabilization world in the late ‘80s,” he says. “It revolutionized it into a full-blown subcontractor-oriented marketplace.”

Say What? Smooth Operators

“The highway system that we have in place today is second to none. In fact, over the last two decades, I’ve watched industry have to incorporate rumble strips – which we did not use to do routinely – because we’re falling asleep at the wheel because the roads are so smooth. We’re putting rumble strips by mandate out there to wake you back up.”

John West

Product Support Specialist

Terex Roadbuilding

The 5

Echoing the words of its fellow milling machine manufacturers, Atlas Copco’s Dynapac offers tips to contractors to get the most out of their planers. According to Tom Chastain, product manager, pavers/planers:

Doing a visual walk-around allows a person to see areas of concern, such as loose or damaged tracks, worn or torn belts, and hydraulic leaks.

Proper daily drum maintenance should be done either before or at the end of the machine’s working shift. Specific attention should be paid for inspection and replacement of milling teeth and holders. Depending on the cutting system, holders may need to be tightened down according to the manufacturer’s specifications.

Washing of the machine is vital. This not only allows the machine to run more smoothly, but this can also prevent premature wear. A clean machine also allows potential issues to be more visible while doing the walk-around inspection.

Daily lubricating of all necessary components prolongs the life of the components and prevents premature failures. Use manufacturer-recommended lubricants, or at least lubricants that have been approved by the manufacturer and/or vendor.

Understanding and communication amongst the crew is critical. The most vital part of a milling operation is a quality crew. If the crew understands the job requirements and has done the proper maintenance on the milling machine itself, the program should go according to plan . . .

Well, adds Chastain, as much as it can, that is: Job scenarios do change seemingly every minute.

Nanotech era draws closer

By Tom Kuennen, Contributing Editor

Nanotechnology offers long-term promise to boost performance of our highway, road and bridge infrastructure. New research is expanding and new applications are materializing. More recently, the long-term environmental impacts of nanomaterials are being studied. But implementation is going to take a long time.

The impact of nanotechnology on highway, road and bridge transportation infrastructure is just beginning. Nanotechnology involves the characterization, engineering and fabrication of matter at the molecular nanoscale, to improve existing products and to make feasible new materials and processes.

Nanoscale crystal seeds speed up concrete hardening. BASF’s X-Seed hardening accelerator makes additional heat superfluous and the concrete is particularly strong and durable. Magnification 960:1 (by 12 cm in width).

Nanotechnology embraces the nanoscale; that is, the range of dimensions from approximately 1 nanometer to 100 nanometers (1 to 100 billionths of a meter). One nanometer is 100,000 times smaller than the width of a human hair. That’s a molecular domain in which devices and systems exhibit properties that aren’t seen at larger scales. In that domain of quantum physics, clusters of atoms and molecules exhibit properties quite different from those found at larger scales. These properties have applications for pavement and bridge infrastructure.

“Nanotechnology should not be implemented in the pavement engineering arena merely because it is a new technology,” states Wynand Jacobus van der Merwe Steyn, Department of Civil Engineering, Tshwane University of Technology, Pretoria, in his paper, Development of Auto-Luminsecent Surfacings for Concrete Pavements. “[T]he application of nanotechnology should allow the engineer to deliver a better product to the client. This may, for instance, be a more cost-effective product, a more technologically suitable product or a safer product.”

Nanotechnology can focus on improving the general properties (e.g., strength, durability) of current materials, the ability to use marginal materials, or the novel application of nanotechnology to enable a safer transportation environment, Steyn says.

Nanomaterials and Construction

Nanomaterials offer significant advantages for the construction industry at large, from making more durable concrete to self-cleaning signs or windows. “The advantages of using nanomaterials in construction are enormous,” says Pedro Alvarez, chair of the Department of Civil and Environmental Engineering at Houston’s Rice University. “When you consider that 41 percent of all energy use in the U.S. is consumed by commercial and residential buildings, the potential benefits of energy-saving materials alone are vast.”

But widespread use in building materials comes with potential environmental and health risks when those materials are thrown away. Those are the conclusions of a study published by Rice University engineering researchers in the July 2010 issue of ACS Nano.

“[T]here are reasonable concerns about unintended consequences,” Alvarez says. “The time for responsible lifecycle engineering of man-made nanomaterials in the construction industry is now, before they are introduced in environmentally relevant concentrations.”

In fact, in a 2010 report, Nanomaterials in the Construction Industry: A Review of Their Applications and Environmental Health and Safety Considerations, Alvarez and co-authors Jaesang Lee, a postdoctoral researcher at Rice, and Shaily Mahendra, an assistant professor at UCLA, find that nanomaterials will likely have a greater impact on the construction industry than any other sector of the economy, following biomedical and electronics applications.

Nanomaterials, they find, can strengthen both steel and concrete, keep dirt from sticking to windows, kill bacteria on hospital walls, make materials fire-resistant, drastically improve the efficiency of solar panels, boost the efficiency of indoor lighting and even allow bridges and buildings to “feel“ the cracks, corrosion and stress that will eventually cause structural failures.

But the authors warn of potential adverse health and environmental effects of widespread use of nanomaterials. In some cases, the very properties that make the nanomaterials useful can cause potential problems if the material is not disposed of properly. For example, titanium dioxide particles exposed to ultraviolet light can generate molecules called “reactive oxygen species“ that prevent bacterial films from forming on windows or solar panels. This same property could endanger beneficial bacteria in the environment.

FHWA Coordinates Research

The Federal Highway Administration (FHWA) has been studying applications of nanotechnology to highway infrastructure for more than a decade.

In 2009, FHWA’s Exploratory Advanced Research (EAR) program hosted a workshop to identify interests and capabilities for nanoscale research that can be applied to highways. The workshop attracted experts from FHWA, university transportation research centers, federal labs and other organizations that are conducting nanoscale research.

The workshop helped shape the scope of FHWA’s further investment in nanoscale research, and supported the development of strategic roadmaps that could outline funding needs for future nanoscale research for highway infrastructure.

“We expect the nanoscale workshop to lead to an overall increase in research targeted at highway program needs,” says David Kuehn, EAR program team director at FHWA. “The workshop was an ideal opportunity to collaborate and leverage nanoscale technology that is being developed for other industries and to accelerate our ability to solve long-term highway research questions.”

“There are multiple potential nanoscale applications in highways,” FHWA says in a 2010 report on the workshop, Nanoscale Approaches for Highway Research. “For example, concrete is a material containing pores on a nanoscale, a result of the chemical reaction between cement and water. Repeated exposure to deicing chemicals causes oxidation, cracks and long-term deterioration to occur in the structure. Utilizing nanotechnology to create smart self-healing materials and structures could lead to less-frequent and faster construction, as well as to increased durability and improved performance, all helping to prevent catastrophic failure.”

Nanotechnology’s ability to produce minuscule MEMS, or microelectronic and mechanical systems, would permit stakeholders to constantly monitor materials, and also could offer improved predictive performance models. “During construction, nanotechnology can allow for embedding increasingly smaller sensors throughout a structure or pavement,” FHWA says. “These sensors could be used for long-term monitoring of corrosion and could offer an invaluable tool in monitoring bridges. By using a car-mounted data reader, information from the embedded sensors could then easily and safely be collected as the vehicle passes.”

As Alvarez, Lee and Mahendra observe, some of this research should be aimed at the environmental aspects of widespread use of nanotechnology, FHWA says. There is concern that unleashing these products on a widespread basis could have unanticipated consequences like something out of a science fiction novel.

Yet nanotechnology in transportation infrastructure also offers environmental benefits, FHWA observes. “[Nanomaterials have the] ability to monitor mobile source pollutants during construction and operations by using nanoscale devices to bind with road-based pollutants,” FHWA says. “Low-cost environmental sensors could monitor the air, water and soil quality, and the technology could allow large-scale monitoring of the operation to continually map pollution levels.”

In a new line of research, nanomaterials such as thin-film technologies may boost use of recycled concrete aggregate (RCA) and reclaimed asphalt pavement (RAP), in addition to reducing alkali-silica reactivity (ASR) in concrete.

“Nanoscale research could lead to an increased use of recycled materials in pavements through a better understanding of bonding at the boundaries of different materials and the design of very thin coatings to improve the workability and durability of recycled materials, which would also help to reduce costs,” FHWA says. “Nanoscale research also could result in the development of smaller, lower-cost sensors, which would use substantially less energy. Self-powered sensors also would contribute to the efficiency and reduced environmental impact of the highway network.”

Concrete Leads Nanoresearch

By far, the most activity in nanotechnology research for pavement and bridge infrastructure has taken place in the concrete industry. There, research is aimed at optimizing concrete strength and durability using nanomaterials, and condition monitoring via MEMS imbedded in the concrete matrix.

For years, the minuscule size of a particle of microsilica admixture has benefited concrete, as the smaller the silica particle size, the greater the surface area that is presented for reaction within the curing concrete. The much smaller size of nanoparticles now makes possible a geometric increase in performance, and that’s one of the areas of research.

Research in concrete nanotechnology has been well-organized. A workshop at the University of Florida in August 2006 was attended by more than 70 participants, with more than 30 presentations, and focused on the development of a Roadmap for [Nanotechnology] Research for Concrete-Based Materials. The roadmap is destination-oriented, with clearly defined outcomes that will greatly enhance concrete technology and the uses of concrete in structures, including housing, bridges, tunnels and pavements.

That 2006 roadmap identifies research needs such as:

• development of high-performance cement and concrete materials as measured by their mechanical, durability and shrinkage properties;

• development of sustainable and safe concrete materials and structures through engineering concrete for different adverse environments, reducing energy consumption during cement production, and enhancing safety with nanoengineering of concrete materials;

• development of intelligent concrete materials through the integration of nanotechnology-based, self-sensing and self-powered materials and cyber infrastructure technologies;

• development of novel concrete materials through nanotechnology-based innovative processing of cement and cement paste; and

• development of fundamental multiscale model(s) for concrete through advanced characterization and modeling of concrete at the nano-, micro-, meso- and macroscales.

The workshop was followed with a September 2007 conference in Arlington, Va. And, in 2008. a Center for Nanotechnology in Cementitious Systems (CNCS) was created at Iowa State University. The CNCS uses nanotechnology to improve sustainability and performance of concrete roads and structures. The cross-disciplinary nature of the center opens the door to exciting research in this new area, including nano devices that could one day monitor and report on the state of hydration in a mixture and correlate that with the risk of cracking, or predict when traffic can be placed on a pavement.

Other nano-based materials or devices could be used to modify or control the rate of hydration to allow for changes in construction practices or prevent weather-related damage during construction, CNCS says.

In the future, CNCS researchers hope to support 10 graduate students through research projects. Initial projects are being developed, including analysis of the effects of shrinkage-reducing admixtures on the morphology of hydrated cement paste and the properties of air voids entrained in the mixture.

Finally, in May 2010, the First International Conference on Nanotechnology in Cement and Concrete was held in Irvine, Calif. More than 100 delegates from 17 countries and 27 states heard 37 technical papers covering nanotechology in concrete.

Concrete Nanoscale

Nanomaterials can boost strength and resistance to permeability in concrete, according to Celik Ozyildirim, P.E., Ph.D., principal research scientist, and Caroline Zegetosky, graduate research assistant, Virginia Transportation Research Center (now Virginia Center for Transportation Innovation and Research), in their paper Exploratory Investigation of Nanomaterials to Improve Strength and Permeability of Concrete.

“Concrete containing various supplementary cementitious materials (SCMs) such as silica fume, fly ash and slag has improved properties,” they write. “Nanomaterials, new SCMs with possible applications in concrete, have the smallest particle size (less than 100 nm). Nanomaterials are reactive because of the small size and large surface area of the particles, and they have great potential in improving concrete properties such as compressive strength and permeability.”

Ozyildirim and Zegetosky studied a variety of nanomaterials in concrete and compared them to conventional concrete, and concrete containing common SCMs. “The potential benefits of using nanomaterials over other SCMs are high reactivity and cost-effectiveness; in addition, smaller amounts are necessary, resulting in less cement replacement,” they write.

Concretes containing nanosilica and nanoclay were prepared in the laboratory, and compared to concretes containing conventional silica fume, fly ash, slag or only Portland cement. Specimens were tested for compressive strength and permeability. The microstructure of selected concretes with improved compressive strength and permeability was analyzed to explain the improvements.

“The results of this study indicate that some of the nanomaterials tested have potential in concrete applications,” Ozyildirim and Zegetosky write. “The microstructure of the nanosilica concrete was denser and more uniform than the conventional concrete microstructure. In addition, the nanosilica had the largest improvement in both compressive strength and permeability among the nanomaterials tested.”

Download their study from the Virginia DOT at virginiadot.org/vtrc/main/online_reports/pdf/10-r18.pdf

Nanocrystals and Concrete

The private sector has been quick to lead the way to nano-enhanced concretes. For example, a new product, X-Seed crystals from BASF, makes concrete cure faster and reduces carbon emissions.

X-Seed has innovated production of precast-concrete components by serving as a curing accelerator, which the company says not only allows precast concrete units to be produced more rapidly and in better quality, but considerably reduces energy consumption and the associated emission of carbon dioxide (CO2) greenhouse gas.

Cement is produced by pyroprocessing limestone, clay and minerals at high temperatures to produce cement clinker. Pyroprocessing consumes enormous amounts of energy, and releases large amounts of CO2 from combusting the fuel (principally coal or natural gas) and from the chemical reaction the combustion enables. Finally, the coarse-grained clinker is ground into a fine, gray cement powder that hydrates after mixing with water. Calcium silicate hydrate and other compounds crystallize out of the cement during this process to form a compact stone matrix in which aggregates and sand are embedded.

Concrete products are manufactured by placing the uncured concrete mix into forms. Only when the concrete has cured sufficiently can the mold be opened and the component removed. At ambient temperatures (68 degrees F) it can take up to 12 hours to cure, which is valuable production time, during which the formwork cannot be reused. To speed production, the mold often is heated with steam. Although this accelerates production, it also demands much additional energy. Moreover, this treatment can lead to internal thermal stresses, discolorations and a coarser surface of the finished concrete part.

“X-Seed makes heat curing, with all its disadvantages, largely superfluous,” says Dr. Michael Kompatscher, responsible for BASF’s European precast concrete component market. “With this additive, concrete hardens just as fast at 20 degrees C (68 degrees F) as it otherwise does at 60 degrees C (140 degrees F), by a adding something that’s already present in the concrete anyway – calcium silicate hydrate (CSH).”

Countless millions of tiny CSH crystals with a diameter of several nanometers are suspended in liquid in X-Seed, BASF says. Because of their nanosize, more very homogeneously distributed crystallization seeds can be accommodated in the same mass, and thereby promote faster growth. When the concrete cures, further molecules from the cement can attach themselves to these CSH “seeds.” The resulting crystals grow more densely and finally interlock to form the compact cement stone.

When conventional cement hydrates, the CSH seeds first have to form spontaneously from several molecules released from the cement, which accidentally come into contact with each other. X-Seed negates this first barrier to crystallization by providing an excess of these tiny crystal seeds. Another factor is that the CSH crystals form in a more homogeneously distributed manner.

Both these effects of the synthetic crystal seeds halve the time to formwork removal at 68 degrees F from about 12 to six hours, without any detectable differences in the final product, BASF says.

Zeolites and WMA

Warm-mix asphalt (WMA) technologies are a family of processes that produce low-energy asphalt mixes that can be placed at significantly lower temperatures than conventional hot-mix asphalt. At least one additive for warm-mix asphalt operates at the nanoscale, Aspha-Min.

Zeolites are nanoporous crystalline alumino-silicates with important attributes. A zeolite is a constituent of a group of commercially valuable minerals – metamorphosed crystals of hydrated aluminum silicates – of interest to industry for a variety of applications. Zeolites have large vacant spaces or cages in their structures that allow space for large, positively charged ions such as sodium and potassium, and even entire molecules such as water.

Aspha-Min is a synthetic zeolite compound, which releases water (H20) into the asphalt mix to improve workability at lower temperatures. Aspha-Min is available as a very fine, white-powdered form in bags or in bulk for silos. The percentage of water held by the zeolite is 21 percent by mass and is released in the temperature range of 212 to 392 degrees F.

By adding 0.3-percent Aspha-Min to the preheated mixture of sand and stone at the same time liquid asphalt is being introduced, a water-based vapor is created. The water released from the crystal causes the binder to expand to a kind of foam, permitting better workability and coating of aggregates at lower temperatures. Tests indicate that 54 degrees F reduction in temperature equates to a 30-percent reduction in fuel energy consumption.

Thanks for the MEMS

Nanotechnology for transportation infrastructure goes beyond engineered materials, into appliances manufactured at the nanoscale. These nanotechnology-driven sensors and instruments – microelectronic and mechanical systems, also called microelectromechanical systems (MEMS) – have the ability to detect motion and monitor corrosion, cracking and performance of structures and pavements under service loads and conditions.

In their 2008 paper, Applicability of Microelectronic and Mechanical Systems (MEMS) for Transportation Infrastructure Management, investigators Kelvin C.P. Wang and Qiang Li, Department of Civil Engineering, University of Arkansas-Fayetteville, describe the application of MEMS for pavements and bridges.

“With the tremendous advancement in technology, it is possible to employ devices embedded in structural members for real-time monitoring of infrastructure health,” they say. “Micro-electromechanical systems are miniature sensing or actuating devices [that] can interact with their environment to either obtain information or alter it. With remote query capability, it appears such devices can therefore be embedded in structures to monitor distresses such as cracking.”

MEMS merge the functions of sensing and actuating with computation and communication to locally control physical parameter at the micro-scale, yet cause effects at much grander scales, they observe. MEMS as devices have static or movable components with some dimensions on the scale of a micrometer, and can be either sensors, actuators or passive structures.

“Sensors are transducers that convert mechanical, thermal or other forms of energy into electrical energy; actuators do the exact opposite,” Wang and Li write. “Passive structures are devices in which no transducing occurs. A fourth classification, hybrid systems, is used for specialized applications. Micromachining and integrated circuit technologies are the foundation of sensors and actuators as well as of MEMS or microsystems.”

MEMS produce smart materials and structures technology, and their applications include structural control, condition or health monitoring, damage assessment, structural repair, integrity assessment and more recently in asset management, preservation and operation of civil infrastructure, they write. “The potential benefit here is improved system reliability, longevity, enhanced system performance, improved safety against natural hazards and vibrations, and a reduction in lifecycle cost in operating and managing the infrastructure. There is no doubt MEMS can . . . assist engineers in infrastructure management to have real-time or quasi-real-time information on the health of the infrastructure.”

In bridges, MEMS technologies are well-suited to improve the performance, size and cost of sensing systems, they say. “MEMS can be used in both monitoring and testing of transportation infrastructure systems,” they write, adding applications in bridge engineering are underway.

In pavements, MEMS have the capability of supplementing, if not replacing, nondestructive testing of pavement condition, they suggest. “Recently, vigorous efforts have been devoted into developing sensing technologies and nano-technology in infrastructure condition monitoring,” write Wang and Li. For crack monitoring purposes, a MEMS transducer has been developed for an ultrasonic flaw detection system, which can be used to detect the initiation of a crack.

Geometrically smaller size of nanoparticles increases the relative surface area available to react with cement in concrete.

Also, networks of nanosensors embedded in roadways could provide real-time information to better manage congestion and incidents, or to detect and warn drivers about fast-changing environmental conditions such as fog and ice. “In recent years, more and more attention has been paid to MEMS-based moisture sensors,” they write. It’s clear that MEMS will play a big role in the intelligent highway systems of the future.

Nanotechnology is leading to self-cleansing signs. The so-called “lotus effect” – which describes the self-cleansing surface of the lotus leaf, which takes place at the molecular level – is being replicated in lotus effect-based self-cleansing nano materials into traffic and work zone signage, and in particular traffic-control devices, which require labor-intensive periodic washing to remove road grime and enhance visibility.

Cleaner air from pavements: Titanium dioxide nanoparticles in both concrete and asphalt pavement surfaces have the ability to remove – via photocatalytic reaction – nitrogen oxides and sulfur dioxide from the atmosphere.

“On a hydrophobic, easy-clean surface, particles of dirt are just moved around by moving water, but on a lotus-effect surface, dirt and grime are collected by water drops and rinse off,” Wang and Li write. “Coatings that mimic the properties of the lotus leaf may well lead to signs that shed dirt and never need washing.”

Thin Film Technologies

Nanoscale research could lead to an increased use of recycled materials in pavements through a better understanding of bonding of different materials, and the design of very thin coatings to optimize use of reclaimed materials.

In their 2010 Transportation Research Board paper, New Possibilities and Future Pathways of Nanoporous Thin Film Technology to Improve Concrete Performance, Jose F. Muñoz of the Department of Material Science and Engineering, University of Wisconsin–Madison, and Richard C. Meininger and Jack Youtcheff of the Pavement Materials and Construction Team at FHWA’s Turner-Fairbank Highway Research Center, find that nanoporous thin films (NPTFs) may improve the interfaces between aggregate and cement paste.

“Aggregates are often considered as inexpensive inert filler material in concrete,” the authors write. “However, the mixture of the aggregate with the cement paste creates one of the most vulnerable areas of concrete, the interface of aggregate and cement paste. The judicious application of nanoporous thin films on the aggregate’s surface is an effective way to improve those interfaces.”

The most recent work on concrete shows that the use of different types of NPTF can induce changes in different properties of concrete or in an aggregate’s mineralogy, the researchers say. The observed improvements in mechanical properties such as compressive, flexural and tensile strengths, modulus of elasticity and drying shrinkage can ameliorate longitudinal and transverse cracking, corner breaks, punchouts and D-cracking, they write.

Improving Traffic Safety

Nanotechnology also has a role in improving transportation safety, according to Satish V. Ukkusuri, Ph.D., assistant professor, and Gitakrishnan Ramadurai, graduate student, Rensselaer Polytechnic Institute, in their 2009 TRB paper, A Comprehensive Review of Emerging Technologies for Congestion Reduction and Safety.

Looking ahead 20 years, the researchers identified future technologies, and focused on nanotechnology, as well as other emerging fields. “Nanosensors have potential to track bioterror agents, stress in materials and detect polluting agents in the atmosphere and tailpipes,” they say. “Nanosensors could be used in transportation to monitor pavement conditions, bridge conditions, pollution deduction, bioterror agent detection and air-quality monitoring.”

The feasibility of “cyberliths,” or “smart aggregates,” as wireless sensors embedded in concrete or soil is being studied. Researchers at Johns Hopkins University’s Applied Physics Laboratory have developed a robust wireless-embedded sensor, suitable for long-term field monitoring of corrosion in rebar, particularly in bridge decks, they say.

“Nanomaterials that are of interest in transportation include carbon fibers that are 100 times stronger than steel, nanocoating of metallic surfaces to prevent corrosion, and nano reinforcements in vehicle bodies, pavements and other transportation infrastructure,” Ukkusuri and Ramadurai write. “Automatic healing materials have potential to be used in guardrails that heal themselves, or concrete or asphalt that heal their own cracking.”

Road Science Tutorial

Nanotechnology Will Transform Infrastructure Will Impact Materials, Monitoring, Maintenance, Safety and Durability

Thin Open-Graded Surfacings Drive Market

By Tom Kuennen, Contributing Editor

Now, more than ever, thin open-graded friction courses (OGFCs) are driving the market for drainable, high-friction, noise-attenuating asphalt mixes.

A thin crumb, rubber-modified, open-graded wearing course is placed on California Highway 1 near Fort Bragg; the mix incorporated a warm-mix additive to ensure workability, following the two-hour drive to the Pacific Coast from the plant.

This new generation of OGFCs is being bolstered by the advent of high-performance “spray” pavers that place thin, polymer-modified OGFCs quickly and with great consistency, and by new materials that halt the potential “draindown” of liquid asphalt within an open-graded mix.

The use of these new OGFCs also is expanding as a result of the general trend toward pavement preservation, as cash-strapped road agencies realize that it’s a lot cheaper to extend pavement life by spending limited funds on preservation techniques at the right time, rather than allow a road to deteriorate to the point of failure, with costly reconstruction the only option.

A conventional OGFC is a layer of asphalt that incorporates a skeleton of uniform aggregate size with a minimum of fines. It features an open aggregate structure in which larger-sized aggregate is held in place by polymer-modified and fiber-modified Superpave performance-graded liquid asphalts. Most OGFCs are 3/4-inch thick, and never thicker than 2 inches.

The OGFC’s open structure of 15 percent or more voids allows water to drain right through the driving or friction course to an impervious intermediate course below, and out into roadside ditches. The result is the near-complete elimination of tire spray and hydroplaning, making a safer pavement and saving lives. It also results in a quieter pavement as noise is attenuated within the gaps between the aggregate. OGFCs should be elevated above the shoulder, as the water drains onto the shoulder and hence to a roadside ditch.

A Variety of Names

Today’s spray-applied OGFCs are known by a variety of names. Oklahoma DOT has expanded the use of what it calls spray-applied ultra-thin bonded wearing courses. In Nevada, they’re known as ultra-thin asphalt concrete surfacings (UTACS, pronounced “you-tacks”), which are gap-graded wearing courses, bonded to the surface by a warm polymer-modified membrane, followed immediately by the hot, gap-graded, ultra-thin asphalt concrete friction layer.

UTACS are similar to Caltrans’ bonded wearing course, “a gap- or open-graded, ultra-thin hot-mix asphalt mixture applied over a thick polymer-modified asphalt emulsion membrane,” to quote the agency. “The emulsion membrane seals the existing surface and produces high binder content at the interface of the existing roadway surface and the gap- or open-graded mix, all in one pass.” Recently, Caltrans has been increasing its use of crumb rubber-modified emulsion for these OGFCs in lieu of polymer modifier.

Such bonded wearing courses are primarily used in high-traffic areas as a surface treatment over hot-mix asphalt or Portland cement concrete pavements. They are placed over structurally-sound pavements as a maintenance treatment, but may also be used in new construction and rehabilitation projects as the final wearing course.

In a bonded-wearing course such as those specified by Caltrans, a polymer-modified asphalt emulsion membrane seals the existing pavement while bonding the gap-graded or open-graded mix to the surface. The thicker nature of the membrane allows it to wick upwards into the mix, filling voids in the aggregate and creating an interlayer of high cohesion that does not delaminate or bleed, if applied correctly.

A predecessor of today’s thin, open-graded wearing course designs is NovaChip, an ultra-thin, bonded, gap-graded wearing course placed by a specialized paver in one pass. This exclusive pavement process applies an ultra-thin hot-mix wearing course over a polymer-rich asphalt emulsion. The process rapidly secures the lift to the existing surface and allows for minimal traffic delays. Originally developed by a French contractor, the patent for NovaChip is currently owned by Colas S.A. and is licensed for use in the United States by Road Science LLC of Tulsa.

But what’s not happening today is an increase in deeper-lift OGFCs. While most states that use them place OGFCs as thin asphalt lifts at 3/4-inch depth or less, the Oregon DOT has been placing 3/4-inch open-graded mixes in structural layers of 2 inches or more for about 30 years, reports Dr. Steve Muench, et. al., at the University of Washington-Seattle, in a June 2011 report for the Oregon DOT. He adds the Washington State DOT has used similar mixes since the early 1990s, although more sparingly. Due in part to the damage done to OGFCs by studded tires used in Oregon, the report recommends that use of 3/4-inch OGFCs be discontinued in the state (see below).

OGFCs for Cold Weather?

Typically, OGFCs tend to be confined to states without severe winters, as it’s perceived that water trapped within the drainable layer can expand and cause the open-graded layer to ravel, or create dangerous icing, leading to accidents.

One cold weather state, Wisconsin, recently looked at OGFCs as used and discontinued by northern-tier states and provinces, and received a recommendation that it not proceed.

“OGFC has historically not been used in Wisconsin due to concerns about its performance in a climate with a large number of freeze-thaw cycles,” says Richard E. Root, P.E., Root Pavement Technology, in his 2009 Wisconsin Highway Research Program report, Investigation of the use of Open-Graded Friction Courses in Wisconsin. “Questions also exist about the cost/benefit of these mixtures.”

The study’s primary objectives were to determine if the OGFC mixture could be successfully used in the Wisconsin climate. After a literature review that listed many northern-tier states that had started “new generation” OGFCs, but had since discontinued them, Root concluded that Wisconsin should avoid them.

“While the use of OGFC mixtures in warm southern climates has been successful, this pavement has not proven to have the same successes in the northern freeze/thaw environment,” Root says. “None of the states or Canadian provinces with climates that duplicate Wisconsin’s use OGFC mixtures. On a routine basis, it is recommended that Wisconsin should not currently build pavements with an OGFC surface.”

This summer, Oregon had reason to abandon OGFCs altogether. In June, a technical report – Open-Graded Wearing Courses in the Pacific Northwest: Final Report by Stephen T. Muench, Ph.D.; Craig Weiland; Joshua Hatfield and Logan K. Wallace of the Department of Civil and Environmental Engineering, University of Washington – suggested that use of the 3/4-inch open-graded hot-mix asphalt (previously referred to as “F-Mix”) be curtailed.

“The best estimated service life of [Oregon] DOT 3/4-inch open-graded HMA ranges from 14 years (< 5,000 ADT) down to seven years (> 100,000 ADT), which is less than comparable dense-graded mixes,” Muench and researchers wrote in June. “The primary mode of distress is raveling and studded tire wear. Reduced service life, along with uncertain and unquantified safety benefits and a possible greater risk of early failure lead to a recommendation to discontinue use of 3/4-inch open-graded HMA in Oregon as a standard surface mix.”

Open-graded wearing courses used elsewhere in this country are not likely suited for use by Oregon DOT, due to their susceptibility to studded tire wear, they say, and the writers don’t recommend their adoption. “If 3/4-inch open-graded HMA does continue in use,” the writers say, “recommendations are [to] quantify its benefits, restrict its use to low-traffic routes (< 30,000 ADT), recalibrate the state’s pavement management system’s expected life to be more in line with observed historical life, and require the use of a windrow pick-up machine or end-dump transfer machine when paving OGFCs.”

Download the new research at http://ntl.bts.gov/lib/41000/41300/41329/SPR680.pdf

Binder Modification Key

Open-graded friction courses have been used since 1950 in the United States to improve the frictional resistance of asphalt pavements, promote drainage of water from pavement and thus reduce tire spray, and reduce noise from the tire/pavement interface.

Spaces within the “open-graded” or “gap-graded” mix — and amounting to as much as 20 percent of the mix or more in some European mixes — help drain water and attenuate tire noise.

OGFCs are attaining a new popularity as states take a look at refined mix designs incorporating additives like polymer modifiers, rubber asphalt, fibers and hydrated lime. But it wasn’t always this way.

Prithvi S. “Ken” Kandhal and Rajib B. Mallick of the National Center for Asphalt Technology (NCAT) at Auburn University published a 1998 survey, Open-Graded Asphalt Friction Course: State of the Practice. The survey showed that, when these pavements were introduced in the 1950s, some states had problems with them. Improvements in OGFCs have made a vast difference. “These improvements have been achieved with the help of good design and construction practices,” they write.

The secret is modification of the asphalt binder. “A vast majority of agencies report good experience using modified asphalt binders,” Kandhal and Mallick say.

Georgia’s experience reflects the OGFC survey. “Early mixes used were very susceptible to premature failure due to weathering,” state Georgia DOT researchers in the DOT’s Progress in Open-Graded Friction Course Development, presented at the Transportation Research Board annual meeting in 1998.

Because of early problems, Georgia put a moratorium on OGFCs in 1982. Likewise, Washington State DOT tried smaller stone-sized (3/8-inch) mixes as thin (0.15-foot) wearing courses in the 1980s and early 1990s, but discontinued their use because of excessive studded tire wear problems.

Porous asphalt pavement is similar to open-graded friction courses (OGFC) but is meant for static loads and environmentally-sustainable stormwater drainage. A mix for the parade ground at U.S. Marine Corps Recruit Depot at Parris Island, S.C., contained Evotherm warm-mix additive instead of fibers.

But in the 1990s, Georgia developed a mix that incorporates a high degree of single-sized coarse aggregate, polymer-modified asphalt binder, stabilizing fibers and hydrated lime.

“This mix has been used extensively statewide since 1993,” the DOT reports. Now Georgia, pleased with its success, is urging other state DOTs to reassess OGFCs. “[Agencies] should reconsider the possibility of using this modified OGFC on high-volume-traffic facilities,” they say. “It is now Georgia DOT policy to use modified OGFC as the final ride surface on all Interstates and on state route projects that have daily traffic volumes exceeding 20,000 and are not in a reduced speed zone area.”

Modified vs. Standard Binders

After Georgia, use of polymer-modified — and more recently, rubber-modified — binders for OGFCs has become common. But the use of polymer or crumb rubber modifiers in OGFC binder may come at a cost: the ability of the pavement to drain water, at least in 4.75-mm nominal maximum aggregate size (NMAS) mixes.

That’s what Qing Lu, assistant professor, Department of Civil and Environmental Engineering, University of South Florida, and John T. Harvey, professor, Department of Civil and Environmental Engineering, University of California-Davis, say in their 2011 Transportation Research Board paper, Laboratory Evaluation of Open-Graded Asphalt Mixes with Small Aggregates and Various Binders and Additives.

Their paper is part of ongoing research to develop alternative asphalt surface mixtures that are quieter and durable without much sacrifice of safety, they say.

Five binder types (PG 64-16, PG 58-34PM, PG 76-22PM, asphalt rubber and PG 76-22TR) and two additives (hydrated lime and cellulose fiber) were selected for a 4.75-mm NMAS gradation, they write. A series of laboratory tests were conducted to evaluate their pavement surface performance-related properties, including acoustic absorption, texture, resistance to raveling, moisture sensitivity, permeability, friction, resistance to permanent deformation and resistance to reflective cracking.

“Results show that using polymer-modified or rubberized binders instead of unmodified binder in the 4.75-mm NMAS open-graded mixture reduces permeability,” they write, “but increases acoustic absorption, with the mixture containing asphalt rubber binder showing the most acoustic absorption improvement.”

Using asphalt rubber also can enhance the mix’s resistance to moisture damage or premature failure, raveling, rutting and potential resistance to reflective cracking. “There are also preliminary indications of friction improvement by replacement of conventional binder with asphalt rubber binder in the small-size aggregate open-graded asphalt mix,” Lu and Harvey say.

Rubber-Modified OGFC Binders

Rubber-modified binders for OGFCs now are seen on the west coast (California) and the east coast (South Carolina), as well as in the epicenter in Arizona.

On Napa Valley’s Silverado Trail, a specialized paver places tack coat at the rate of 0.17 to 0.20 gallons per square yard in advance of rubber-modified open-graded friction course.

Modified asphalt cement binder is required in OGFCs to prevent draindown of the binder and achieve the necessary level of adhesion and mix stability, reports the Asphalt Rubber Technology Service (ARTS) at Clemson University. “Although typically a polymer is used as the modifying additive to the asphalt cement binder, crumb rubber made from scrap tires may also be used as an alternative modifier,” according to the university.

The South Carolina rubber-modified open-graded friction course is placed 3/4- to 1-inch deep, with a crumb rubber content of 12 percent by weight of the liquid asphalt, or 0.85 percent by weight of the mix.

There, OGFC can be placed on either asphalt or concrete pavements, and it consists of roughly 93-percent crushed stone, 7-percent modified asphalt binder and a small amount of stabilizing fibers, Clemson’s ARTS says.

A next-generation polymer-modified open-graded friction course is placed on a Clark County, Nev., street.

“Rubber-modified open-graded friction course has all the same advantages as polymer-modified OGFC,” ARTS says. “Compared to concrete and standard asphalt dense-graded pavements, it has significantly lower noise levels, it has less surface water in wet weather, and it is generally safer in wet weather due to the better visibility and decreased hydroplaning, resulting from the lack of surface water on the pavement surface.”

In addition to sharing all the advantages of OGFC with its polymer-modified counterpart, rubber-modified OGFC also costs slightly less than conventional polymer-modified OGFC, ARTS says, adding when used in OGFC, scrap tires can be used at a rate of approximately 1,000 tires per mile of two-lane pavement.

Fighting Draindown with Fibers

While modifiers will help keep liquid asphalt binder from moving within an open-graded mix, it still may puddle at the bottom of a haul truck, or settle lower in the lift of mix just placed. This “draindown” of asphalt seriously compromises the durability of OGFCs.

The problem of draindown of liquid asphalt is solved by use of fibers – typically cellulose, but also mineral filler – which are used to hold the binder in place.

Tack coat eliminated: Movable bars spray polymer-modified emulsion tack coat in advance of thin-lift open-graded UTACS friction course in Clark County, Nev.

While cellulose fibers are most often used, new research indicates that polyethylene fibers may do the same thing in OGFCs. In the technical paper Characterization of OGFC Mixtures Containing Reclaimed Polyethylene Fibers written by V.S. Punith, of the Asphalt Rubber Technology Service at Clemson University, and A. Veeraragavan, Department of Civil Engineering, Indian Institute of Technology, Madras, and published last year in the Journal of Materials in Civil Engineering, it was reported that polyethylene fibers derived from recycled low-density polyethylene (LDPE) tote bags performed in OGFC mixes.

Polyethylene fibers recycled from LDPE bags collected from domestic waste improved OGFC mixes without fibers, they say. “Draindown test results indicated that OGFC mixtures with polyethylene fibers can be effectively used to retard draindown of the binder and mineral filler,” they write. “[T]est results indicated that OGFC mixtures with reclaimed PE fibers showed improvement in tensile strength and improved resistance to permanent deformation, fatigue-induced damage, and moisture susceptibility, when compared with mixtures without fibers.”

Draindown in Porous Mixes

While porous asphalt pavements are open-graded to encourage water drainage, they differ from open-graded friction or wearing courses by structure and function. Yet, they pose many of the same challenges as OGFCs, including binder draindown.

Porous asphalt pavement is an environmentally-sustainable infrastructure design that helps property owners manage stormwater effectively and inexpensively. They are specified for static traffic areas such as parking lots, and aren’t suitable for wearing courses.

Typically, a porous asphalt pavement will be composed of, from the bottom, an uncompacted soil subgrade that will optimize infiltration of water into the aquifer; a geotextile fabric that will permit water to pass but preclude movement of fines up into the structure; a stone recharge bed with same-sized aggregate and 40 percent voids; an optional stabilizing or “choker” course of single-size crushed stone smaller than that in the recharge bed; and an open-graded asphalt surface with 20-percent voids that permit stormwater to flow through the pavement into the stone recharge bed.

While OGFCs shoot for voids of 15 percent to control spray and noise, porous asphalt pavements let water drain directly into a recharge layer below, and the air-void target is 20 percent. The porous asphalt “green grinder,” or parade ground, constructed at the U.S. Marine Corps Recruit Depot at Parris Island, S.C., in May 2011 was not intended to reduce spray, hydroplaning or noise, but simply to provide the most efficient means of draining water from the paved surface and into the soil, while avoiding conventional detention ponds.

While fibers conventionally are used to stabilize porous asphalt mixes, an innovative warm-mix asphalt design for Parris Island saved money by eliminating fibers required for stability of the open-graded mix. The porous asphalt design also eliminated the expense of creating a detention pond and associated environmental requirements.

The elimination of fibers from the Parris Island mix was achieved by use of a warm-mix asphalt additive, Evotherm 3G from MWV Asphalt Innovations, which adds lubricity to individual microscopic asphalt particles, permitting production of asphalt at significantly lower temperatures than conventional mixes.

Evotherm stops the draindown of liquid asphalt by virtue of the lower mixing temperature it enables. “We were able to make the mix at 285 degrees F, instead of 350 degrees, which completely eliminates the problem of draindown,” says Dean Frailey, business development manager, MWV Asphalt Innovations. The mix was emerging from the truck at approximately 275 degrees and from the screed at about 245 degrees. No liquid asphalt was visible in the truck bed as mix was fed to a material transfer vehicle ahead of the paver.

CRM Binder in California

Crumb rubber-modified binder was used recently for an ultra-thin, open-graded wearing course in California’s Napa Valley. In the town of Napa, a 10-year-old asphalt overlay on the Silverado Trail was showing signs of wear over a 2.9-mile section. There was minor cracking, some raveling and a few areas required full-depth asphalt patching. But for the most part, the road was in good shape; it was structurally sound.

To preserve the road and extend its life, Caltrans turned to an ultra-thin bonded wearing course. In this process, a Roadtec SP-200 paver sprays a tack coat down just in front of the spreading augers, and the screed levels off a 3/4- to 1-inch-thick layer of open-graded hot mix.

On California Highway 50 between Placerville and South Lake Tahoe, an ultra-thin bonded wearing course lasted seven years, says Brian D. Toepfer, maintenance engineer, Caltrans. “I think it [performs] better than a mill-and-fill, and it is a lot less expensive.”

On the Silverado Trail, the Construction Division of Telfer Oil, Martinez, Calif., used the specially-equipped paver to spray down a heavily polymer-modified emulsion at a rate of 0.17 to 0.20 gallons per square yard. “The emulsion is similar to a PMCRS-2H emulsion, which is a standard chip sealing emulsion,” says Karl Meyers, general manager of Telfer’s Construction Division.

The paver immediately followed the emulsion with a 7/8-inch-thick layer of open-graded hot mix made with PG 64-16 liquid asphalt that was modified with crumb rubber. The target value for binder content was 8.5 percent, and the top-size aggregate in the mix was 3/8 inch. It also contained a small amount of sand.

Static compaction with two double-drum rollers followed the paver. “You have to run two rollers because you need to hit the temperature range on compaction, which is 180 to 280 degrees,” Meyers says. “That thin lift behind the screed is cooling fast, and you want to release the road to traffic quickly. Plus, the paver is moving at 70 to 100 feet per minute, so you need to run two rollers behind.”

The process has a number of advantages, Meyers says. “You are not getting any tack coat dragged around the city, you get an outstanding bond with the hot mix, you are forming a waterproof membrane, there is no water splash, and you can release the road quickly to traffic,” he says.

Polymer-Modified UTACS

In the meantime, a specialized paver has given a Las Vegas asphalt contractor entry into the growing market of ultra-thin asphalt concrete surfacings in Nevada and throughout the Southwest.

However, to correctly place UTACS or other bonded wearing courses, the right kind of paver is needed: One that has the ability to spray asphalt emulsion onto a pavement, and then immediately place a thin overlay on top. Las Vegas Paving found the Super 1800-2 with optional SprayJet module from Vögele fit the bill.

With its new Super 1800-2 SprayJet paver, Las Vegas Paving now is able to undertake pavement preservation contracts as agencies like Clark County, Nev., use available funds to prolong the life of pavement structures in its desert locale.

Las Vegas Paving acquired its Super 1800-2 SprayJet in early 2010, and has been using it for UTACS ever since. “We were the new kids on the block with this process,” says Clark Webster, general superintendent. “2010 was our first year paving UTACS, and we were concerned that interest would not last, but agencies are still interested.”

Late in 2010, Las Vegas Paving was applying a UTACS to busy Jones Avenue between Tropicana Avenue and Russell Road for the Clark County Department of Public Works. This 2,700-ton job involved three lanes each way, including shoulders and turn pockets. “Jones Avenue is a piece of a larger contract we have with the county, with each piece being anywhere from 15,000 to 20,000 square yards of UTACS,” Webster says. “Jones was a 1-inch deep UTACS, with almost 100-percent passing 1/2-inch with some fines.”

On Jones, warm polymer-modified emulsion was being sprayed directly ahead of the screed via spray bars on each side of the Super 1800-2 SprayJet at a rate of 13/100-gallon per square yard. “It’s not unlike a prime or tack coat, but it provides much more coverage,” Webster says. “And no one can run on it. The Super 1800-2 places the coat behind the wheels but ahead of the material, so cars or our haul vehicles can’t drive over it and pick up the sticky, polymer-modified emulsion. It gives us the best of both worlds – we are able to use a polymer-modified emulsion without having the mess of tires tracking it everywhere.”

Ward Nye, president and CEO of Martin Marietta Materials, says in the MMM earnings report that “despite a continuing difficult operating environment,” he is pleased with the company’s performance.

“That we were able to increase prices and control costs is a credit to our operating teams and our disciplined approach to managing our business,” Nye says in a written statement about the earnings. “Specifically, in the quarter, aggregates pricing momentum continued with a 2.6% increase in the average selling price of our heritage aggregates product line. The quarter was, unfortunately, challenged by erratic weather as well as reduced spending on infrastructure projects. Therefore, as has been the case in the recent past, volumes were significantly lower, and that had an attendant negative effect on our operating profits. Our Specialty Products business continued its exceptional performance and established new quarterly records for both net sales and earnings from operations.”

NOTABLE ITEMS (ALL COMPARISONS, UNLESS NOTED, ARE WITH THE PRIOR-YEAR QUARTER)

– Earnings per diluted share of $0.78 compared with $1.18.

– Consolidated net sales of $426.7 million compared with $442.8 million.

– Heritage aggregates product line pricing up 2.6 percent.

– Heritage aggregates product line volume down 9.3 percent.

– Heritage aggregates product line direct production costs down 2.5%, despite a 13 percent increase in energy costs.

– Specialty Products record quarterly net sales of $49.6 million and earnings from operations of $19.3 million with a 380-basis-point improvement in operating margin (excluding freight and delivery revenues).

– Consolidated selling, general and administrative expenses down $1.9 million, or 20 basis points as a percentage of net sales.

– Consolidated earnings from operations of $63.0 million compared with $b90.7 million.

– Acquired an aggregates, asphalt and ready mixed concrete business in San Antonio.

Sales in the second quarter of 2010 were 344,000 tons generating revenue of $4.72 million, compared to sales of 487,000 tons and revenue of $6.22 million in the comparable prior year quarter. Sales for the first six months of 2010 increased by 3.9 percent to 720,000 tons compared with sales of 693,000 tons for the prior year with revenue increasing by 5 percent to $9.61 million from $9.14 million in 2009.

Underlying prices for the company’s construction aggregates products, net of fuel cost adjustments, remain stable.

For the news release and more details on the financial results from Polaris Minerals, click here.

Both reclaimed asphalt and roofing shingles contain some of the same liquid asphalt and crushed stone content used in virgin asphalt pavement. INDOT previously allowed a limited amount of reclaimed asphalt pavement and new roofing shingles discarded at the factory to be included in hot-mix asphalt. Starting this April, INDOT contractors can use an increased amount of these materials, as well as post-consumer shingles torn off existing roofs.

Recycled materials are tested to make sure the overall asphalt mix meets or exceeds standards for safety, durability and longevity set by the American Society of Testing Materials and the American Association of State Highway and Transportation Officials. Because liquid asphalt is a petroleum-based product, the change also reduces Indiana’s dependency upon imported crude oil.

Reclaimed asphalt pavement and post-consumer roofing shingles are on a growing list of recycled materials finding their way into Hoosier roadways. Most of the concrete and asphalt pavement removed during Indiana road resurfacing and rebuilding projects is reused for the roadway infrastructure, rather than being hauled to a landfill.

For example, old concrete can be crushed up and used to build a new road’s sub-base while asphalt millings are often compacted along the pavement edge to form the soft shoulder. Waste byproducts from Indiana’s steel and coal industries, known as slag, have been used within asphalt mixes for a number of years to provide structural support. These materials take the place of aggregate that would otherwise be mined out of the ground at a nearby quarry and then trucked in to the construction site.

“Indiana is one of the leading states in the country in using recycled materials in its highways,” said Ron Walker, manager of INDOT’s Office of Materials Management. “Recycling existing concrete and asphalt pavement makes use of a valuable resource previously financed by Indiana’s taxpayers.”

As research in this field continues, INDOT hopes to make increasing use of recycled paving materials in the future.

For the full press release, including tables and a breakdown of earnings, click here: Vulcan_4Q2009PressRelease.

The following are the fourth quarter summary and comparisons with the prior year:

· Net earnings from continuing operations were a loss of $13 million, or $0.10 per diluted share.

· Cash earnings from continuing operations were $67 million.

· Aggregates shipments declined 23 percent, reducing earnings $0.57 per diluted share.

· Aggregates pricing increased 5 percent.

· Aggregates cash fixed costs decreased 8 percent.

· Selling, administrative and general expenses decreased 7 percent.

· Total contract awards for highways increased 13 percent in Vulcan-served states

Don James, Vulcan’s chairman and CEO, said in a written statement, “Our employees continue to run the business in a cost-efficient manner, maximizing our cash generation during the economic downturn. Their efforts in the fourth quarter contributed to further reductions in cash fixed costs in our operations as well as reductions in overhead expenses.”

James noted that continued weakness in private construction activity, uncertainty surrounding the timing and amount of either a formal extension or reauthorization of the multi-year federal highway program, and extremely wet weather suppressed momentum gained from stimulus-related construction.

However, he said that Vulcan finished the year with strong cash generation.

For the full year 2009, free cash flow was $343 million, an increase of $261 million from the prior year, and cash earnings per ton of aggregates remained in-line with the prior year.

“We continue to believe that 2010 will be the biggest year for stimulus-related highway construction,” James said in a written statement. “Economic stimulus funds of $27.5 billion designated for highway projects under the American Recovery and Reinvestment Act of 2009 buoyed contract awards for highways in the second half of 2009.

“Despite the failure of Congress to pass a fully-funded extension of SAFETEA-LU, the previous highway authorization that expired on September 30, 2009, contract awards for highways in the fourth quarter increased 9 percent from the prior year,” James continued. “Vulcan-served states, which were apportioned 55 percent more funds than other states, generally have lagged the rest of the country in awarding contracts and starting stimulus-related construction. In the fourth quarter, however, contract awards for highway projects in our states increased 13 percent from the prior year versus a 2 percent increase in other states. We are encouraged by the increased award activity and are optimistic that stimulus-related highway projects in Vulcan-served states, after a slow start, are now moving forward and will benefit demand for our products in 2010.”