A SCRANTON GILLETTE COMMUNICATIONS PUBLICATION A SUPPLEMENT TO

A SCRANTON GILLETTE COMMUNICATIONS PUBLICATIONA SUPPLEMENT TO ROADS & BRIDGES

VIEWPOINT

It’s no secret these

are trying economic

times in which we

are now living. Many

people have called

this prolonged and

persistent reces-

sionary cycle the

worst economic cri-

sis since the Great

Depression. “Do

more with less” is the reality that we are all fac-

ing on a daily basis. Despite these sometimes

difficult current realities, it is important to guard

against the unintended consequence of pulling

in the reins so much that customers and suppli-

ers of products and services become isolated

and even polarized. Businesses need each

other in any industry community. No one does

business alone. A loss of institutional knowl-

edge and expertise, and even a breakdown

in the faith and confi dence that exists among

stakeholders, would take years to overcome.

There are no simple answers to these chal-

lenges, but we humbly offer three solutions that

we hope will preserve, and possibly strengthen,

your bottom line and your business relation-

ships while you navigate your way through

these times:

Keep the lines of communication open. Let’s •

face it, it is not just you. Everyone is busy

these days, and chances are they are not

only working hard at their jobs, but each per-

son also is carrying the extra weight of hav-

ing to tackle more issues. It is important to

stay in contact and to share information with

people who have similar interests and likely

are facing similar challenges. They may very

well provide the idea or solution you need.

Chances are they (and you) will benefi t from

a well-timed phone call, e-mail or visit, espe-

cially if that contact is aimed at some problem

solving;

Invest in continuing education and training. •

Often one of the fi rst business expenses

cut in tough times is employee training, but

this is a practice that defi nitely costs a busi-

ness more in the long run and may affect the

short term too. It is common experience that

well-trained employees improve a business’

efficiency and effectiveness. The benefi ts of

training may even be greater in tough times

when each decision carries more impact.

While no technology-based training can beat

forums where experts can personally transfer

the latest technology and share best prac-

tices, they can give your employees valuable

information at a fraction of the cost of tradi-

tional training courses. One- or two-hour we-

binar formats and self-directed online training

allow participants to fi t training into their busy

daily work requirements without the time or

expense of traveling to a training venue; and

Put your industry association to good use. •

As an association professional for more than

20 years, I realize that the value a business

derives from an association is in direct pro-

portion to its level of participation in the or-

ganization’s activities. Trade and professional

associations unite companies and organiza-

tions that have common interests and needs.

Especially now when the economic climate

limits business opportunities, we encourage

you to increase your involvement, not step

back. We encourage you to be well repre-

sented in actions that will directly infl uence

the paving materials, equipment, specifi ca-

tions, design requirements and construction

best practices that defi ne your opportunities

for new business.

No economic cycle lasts forever, and the

challenging times of today will give way to a

cycle of growth.

While we all anxiously await more signs of

recovery, let’s not forget that now, more than

ever before, we need each other in this industry

community. •

Voigt is president and chief executive offi cer of the American Concrete Pavement Association, Skokie, Ill.

Applying anecdotes could help you through the tough times

Turn three solutions

By Gerald F. Voigt, P.E.

A SCRANTON GILLETTE COMMUNICATIONS PUBLICATIONA SUPPLEMENT TO ROADS& BRIDGES

On the cover: Workers check progress during the con-struction of the Lewisville Lake Toll Bridge.

Features3 WITHOUT

THE RIPPLES Crews work

through chal-lenges on the lake with the right design, equipment

8 CONNECT FOURTH

A closer look at what went into the Illinois Toll-way’s extra lane on the Tri-State

11 FIXING AIR HOLES

Latest research presents method-ology to prevent climate change

15 FIXING FAULT Pavement resto-

ration helps cure faulted pavement on I-44

18 URBANOUTFITTING

Contractor speeds through heart of St. Louis behind design-build schedule

S2 / CONCRETE PROGRESS www.ROADSBRIDGES.com

CONCRETE PROGRESS / S3

Don Talend

LL ewisville Lake, a 23,280-acre lake located just

northwest of Dallas, is a favorite of area sailboaters

and fi shermen, but in recent years, it hasn’t done

much for drivers.

Two major north-south arterials that stretch north of Dallas,

I-35E and the Dallas North Tollway, straddle the lake and cur-

rently no east-west connecting route exists between the two.

Circumventing the lake to get from one arterial to the other

takes drivers half an hour or more.

Part of the solution to this problem will be a 2.03-mile-long

toll bridge which opened to vehicular traffic in August 2009.

Combine a high-profi le bridge project, a fast-track schedule

and a big lake, and the contractor needs the most high-tech

tools it can fi nd to survey the structure with pinpoint accuracy

amid strong wave action.

The North Texas Tollway Authority (NTTA) awarded Des

Moines, Iowa-based Jensen Construction Co. a $93 million

contract to erect a bridge over the lake. The company began

work on a 1,000-ft-long fl ow-easement bridge on the west side

of the lake in late 2006 and then started constructing the lake

bridge in February 2007. This contract is the centerpiece of

roughly $220 million in congestion-easing road improvements

to be made to a surrounding 13.7-mile corridor.

The center of the bridge has a tied-arch span that supports

the bridge deck with cable hangers. This segment also features

a 370-ft-long center span with the bents, i.e., piers, spaced to

allow plenty of room for boat traffic to pass under the bridge.

Two arch bents supporting the center span, combined with an

arched steel-truss structure, give the structure a distinctive ar-

chitectural appearance as the arch bents themselves resemble

sails. Adding to the nautical appearance of the structure are

four more pairs of “light bents,” which resemble lighthouses and

shine light to the north and south of the bridge.

The majority of the spans were designed to utilize pre-

stressed concrete beams, which have a typical length of 120 ft.

Bexar Concrete, San Antonio, precast the beams, deck panels

and skirt panels and trucked them to the jobsite. At a dock in

Lake Dallas on the west side of the lake, the precast elements

were unloaded onto barges, shipped and erected.

The time frame on Jensen’s contract was only 30 months,

meaning productivity was king. Ryan Cheeseman, P.E., the

project engineer for Jensen Construction, fully recognized that

Without theripplesCrews work through challenges on lake with the right design, equipment

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time was money on this project. “It’s the most work in the least

amount of time that we’ve done,” Cheeseman noted.

As a result of the tight schedule, Jensen Construction used

equipment and practices that increase construction efficiency as

much as possible while maintaining adherence to design toler-

ances. Two examples were the use of special light-bent and arch-

bent footing forms that also worked as temporary cofferdams,

and Global Navigation Satellite System (GNSS) receivers for sur-

veying most of the bridge substructure and superstructure.

The use of these items had gone a long way toward keeping

the project on schedule as of just before Memorial Day 2008,

when the building team reached the halfway point. The bridge

had remained on schedule to that point despite challenges

such as an unusually wet May in 2007 in which an 8.34-in.

rainfall total was recorded at Dallas/Fort Worth International

Airport. The area saw even more rainfall in June 2007: more

than 11 in.

Bent on footingsThe most unique design and construction aspects of the

Lewisville Lake Toll Bridge are the arch bents, light bents and

the footings supporting these bridge bents.

These bent footing forms also are temporary cofferdams.

While conventional cofferdams are constructed by driving

sheet piling into the bed of a body of water, building a seal

around the base of the sheet piling and pumping out the enclo-

sure, the footings on this project have replaced the sheet piling

with a concrete footing cast above the surface.

“Conventional cofferdams are very, very tedious and time

consuming and they cost a lot of money,” Cheeseman noted.

“With this type of footing, we were able to complete that whole

footing in about a week and a half, which kept things mov-

ing really quickly. It’s just like a temporary cofferdam using the

formwork of the footing as the cofferdam.”

Drilled-shaft casings—which are 60, 72, 84 or 96 in. in diam-

eter—were driven into the lake bed by ATS Drilling, Fort Worth,

Texas. A 1-ft-thick footing bottom slab was cast on a barge and

the footing forms were set on the bottom slab. The forms and

slab were then set on top of the drilled shafts and supported

by steel hangers welded to the drilled-shaft casing. Workers

pumped out water, installed the rebar and placed concrete for

the footing. Divers stripped the footing,

and skirt panels were hung on the sides

of the footing. Finally, a footing cap was

placed to get the footing to grade.

The arch bents are hollow and have a

thickness of 2 ft 6 in. Each bent required

fi ve concrete placements prior to con-

struction of the bent caps. A vertical sec-

tion facing the center of the lake was cast.

Then a sloped section facing the shore-

line was formed and cast. At the top of

these two sections, a slab was cast that

formed the fl oor of utility rooms. Another

vertical section that forms the utility room

walls was cast on top of the slab, and the

fi fth placement was the roof of the utility

rooms. The caps were then constructed on top of the bents

and supported the beam seats. All columns and caps on the

project were mass-concrete placements and required temper-

ature-controlled concrete. The concrete supplier, Dallas-based

TXI, used liquid nitrogen in the batching concrete to reduce

the heat of hydration in the cement paste—one of the most

extreme measures available for reducing concrete tempera-

ture in massive concrete structures. Temperature-monitoring

devices were being used to check core temperatures vs. ex-

ternal temperatures and safeguard against the potential for

structural cracking.

Teaming Russia with U.S.Jensen Construction used Topcon HiPer Lite+ GNSS re-

ceivers to survey the bridge substructure all the way up to the

beam seats. Cheeseman pointed out that GNSS was used

where possible to address productivity and logistical issues.

A Topcon GTS-235W total station was used for profi ling each

of the girders for setting the decking, he noted, and on the su-

perstructure, the total station was used for deck and paving

grades. In these areas, he explained, maximum pinpoint ac-

curacy was essential. Still, the GNSS equipment is normally

accurate to within roughly fi ve-eighths of an inch of target on

a typical day.

In recent years, surveyors have begun to rely on GNSS

equipment for more and more topographical surveying work

once control is defi ned on a work site. These systems use a

“rover”—a rugged GNSS receiver/antenna that the surveyor

moves from one location to another—and a base station, the

latter of which is located at a known stationary point on the site.

Satellites send positioning data to the base station and to the

rover. The stationary base and mobile rover work together to

provide accurate topographical data. Recently, these systems

have become even more reliable and accurate as they have

added compatibility with the Russian GLONASS satellite con-

stellation as well as the U.S. Global Positioning System satellite

constellation. This dual-constellation capability roughly doubles

the number of signals available to the GNSS antenna/receivers

and provides a high degree of positioning accuracy.

Working on water with strong winds and currents does make

the use of GNSS surveying equipment a benefi cial option

The most unique design and construction aspects of the Lewisville Lake Toll Bridge are the arch bents, light bents and the footings supporting these bridge bents.


where feasible, Cheeseman said. A professional surveying fi rm

was fi rst brought in to defi ne control, and as the fi rst footings

and bents were being constructed, Cheeseman and Jensen’s

surveying team had several “crow’s nests” constructed along

the shoreline. These used 24-in. pipe pile-driven into the lake

bed and small iron work platforms welded to the top of the pipe.

But the wave action on the lake caused slight movement of the

crow’s nests and compromised surveying accuracy.

“We used the crow’s nests just enough to get the control

traversed from one side to the other and got coordinates de-

fi ned, and from that point we just kind of abandoned them

because they weren’t doing us any good,” said Cheeseman.

“They moved so much with the wave action that we couldn’t

set up an instrument and be confi dent that every day we were

going to repeat our locations.”

Cheeseman, along with Jensen Construction surveyors

Laine Buller and Marcus Marion, had already spearheaded ef-

forts to start incorporating the use of GNSS surveying equip-

ment into the company’s bridge work. Before work began on

the Lewisville bridge project, Jensen Construction purchased

the HiPer Lite+ unit from Griner & Schmitz, a distributor of sur-

veying and construction equipment in Kansas City.

“From a productivity and constructability standpoint, we went

to the [GNSS] knowing we could get to within a tenth of a foot

or better every day, so we just ran with it,” Cheeseman said.

The total station maintained its place where ultra-pinpoint

accuracy was necessary on this project, but the location of the

GNSS receiver was less dependent on a level, stable surface

than the total station, so Jensen Construction’s surveying crew

could spend more time surveying from a wider range of loca-

tions without devoting as much time to equipment setup. Signal

reliability was not much of an issue on this project, Cheeseman

added. Noting that the receiver got signals from the base sta-

tion located on high ground all the way to the other side of the

lake—a distance of about 10,000 ft—he pointed out that signal

loss was rare.

The learning curve on the GNSS equipment was short,

the surveyors said. Terry Gammill, sales manager at Griner &

Schmitz, trained Jensen Construction’s surveying crew on the

equipment for a few days following delivery.

“We had a few issues a couple of times and Terry has dealt

with another one of our surveyor engineers and was extreme-

ly helpful,” said Buller, who has been a surveyor for about 10

years and joined Jensen Construction for her second stint at

the start of the Lewisville Lake Bridge project. “He could talk us

through how to fi x it over the phone and that helped a whole

bunch in the beginning.”

The technology was admittedly a bit intimidating at fi rst in that

the crew double-checked the accuracy of the readings with the

total station. As the total station verifi ed the accuracy of the GNSS

equipment, the confi dence grew. Buller noted that she checked

two control points every morning to ensure accurate references.

“We would go out on the lake and then when we came back,

we checked the point as we got on land every time just to make

sure it didn’t get switched around,” she added.

The leap in productivity from using the GNSS equipment

was noticeably signifi cant, Buller said. “I think it would have

taken two other surveyors” to maintain the level of productivity

that Jensen Construction enjoyed without the use of the equip-

ment, she said. “We love this [GNSS] because you carry it out

there and there’s no setting it up and going back to shoot your

backsight. It’s excellent, especially on this water.”

25,000 cars a dayThe structure is expected to handle 25,000 cars a day and

drastically reduce commute times for many. Drivers with elec-

tronic-collection-capable toll tags pay $1, and others pay $1.25.

Undoubtedly, many drivers will gladly pay tolls in exchange for

less “windshield time.” For example, the NTTA estimated that

the bridge will reduce the driving time from Lake Dallas, the

location of the overfl ow bridge on the lake’s west side, to Little

Elm on the east side from 45 to 10 minutes. Thanks to inno-

vation and technology, the Lewisville Lake Toll Bridge itself is

joining drivers on a fast track. •

Talend of Write Results, West Dundee, Ill., is a publicity and communica-tions project manager specializing in the construction industry.

LearnMore! For more information related to this article, go to:

www.roadsbridges.com/lm.cfm/rb110901

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Paul D. Kovacs and Steve Gillen

SS ince it fi rst opened in 1958, the Tri-State Tollway

(I-94/I-294/I-80) has stimulated economic growth

and development in the northern Illinois region.

But after nearly 50 years of service to ever-increas-

ing traffic, much of the Tri-State’s pavement was reaching the

end of its life cycle, and a major overhaul was needed to re-

duce congestion and improve service and road conditions for

tollway customers.

In 2004, the Illinois State Toll Highway Authority approved

a comprehensive $6.3 billion capital program including road

improvements on the North/Central Tri-State from Balmoral

Avenue near O’Hare International Airport to the Wisconsin

state line.

Budgeted at $1.3 billion, the North/Central Tri-State Rebuild

& Widen Project ranks as the largest construction project in

Illinois Tollway history.

CONNECTfourth

A closer look at what went into the Illinois Tollway’s

extra lane on the Tri-State

Heavily numberedThe entire 83-mile Tri-State Tollway func-

tions as a bypass around the metropolitan

Chicago area and serves as a commuter link

between Milwaukee and Chicago. Stretching

from just west of Indiana north to the Wiscon-

sin state line, it serves hundreds of thousands

of northern Illinois commuters, commercial

truck drivers and thousands more local busi-

nesses daily, as well as a multitude of visitors

who arrive in Chicago each day at O’Hare In-

ternational Airport.

Traffic in this corridor has grown dramatical-

ly in the past several decades, as more com-

mercial, residential and retail developments

have emerged. In 1959, there were an esti-

mated 43,000 vehicles a day traveling on the

Tri-State. In the 1970s, when a third lane was

added in each direction, average daily traffic

skyrocketed to about 275,000 vehicles a day.

Today, there are nearly 564,000 vehicles a day

traveling on the Tri-State Tollway.

To address current and future needs, the

scope of work on the North/Central Tri-State

Project included reconstructing and widening

to four lanes in each direction between Bal-

moral Avenue and Rte. 173 near the Wiscon-

sin border.

Work also included reconstructing the road-

way in the 2½-mile segment north of Rte. 173

to Russell Road and resurfacing pavement in the 1½-mile

stretch from Russell to the Wisconsin state line.

The project also widened and reconstructed nearly 60 bridg-

es, rebuilt about a dozen interchanges and reconstructed two

mainline toll plazas—all while maintaining efforts to minimize

disruptions to tollway customers.

Over the course of the project, the Tollway Authority recon-

structed more than 270 lane-miles of pavement, moved 8 mil-

lion cu yd of earth, used more than 1 million tons of steel and

poured more than 1.4 million cu yd of concrete. On any given

day, as many as 3,500 full- and part-time professional and con-

struction staff worked on this project.

What’s old is newThe original roadway was built with a 10-in. jointed reinforced

portland cement concrete (PCC) pavement, which was standard

at the time, and a porous granular material on top of a select

dense-graded aggregate sub-base. But higher-than-anticipated

traffic took its toll on the road, accelerating its deterioration over

time. And after three rehabilitation/overlay projects, it was time

for a complete reconstruction.


Plans for the rebuild and widen project entailed referencing

the American Association of State Highway & Transportation

Officials design guide in order to design the roadway in ac-

cordance with materials standards. Material specifi cations,

as well as quality control and quality assurance, were in line

with Illinois Department of Transportation (IDOT) standards for

pavement and any reinforcements.

From the start, the Tollway planned to recycle 100% of the

existing roadway concrete and asphalt during reconstruction

work. It also recycled concrete from the old Culligan Inter-

national Co. office building in Northbrook and miscellaneous

other sources as well. In total, the Tollway recycled nearly 1.6

million tons of concrete and asphalt as new pavement base ag-

gregates on the Tri-State Tollway, including more than an addi-

tional 200,000 tons of reclaimed asphalt pavement (RAP) from

other sources in the new hot-mix asphalt (HMA) mixtures used

for the HMA stabilized sub-base and new bituminous shoul-

ders of the Tri-State.

Reusing existing roadway materials was not only an envi-

ronmentally sensitive construction method, it also saved con-

tractors and the Tollway money in hauling fees and allowed

better quality control of materials. The extensive recycling ef-

forts required the contractors and the Tollway to apply extra

quality-control and quality-assurance practices to confi rm that

consistent and acceptable materials were being produced.

Work began in 2006, with the 3-in. HMA overlay being milled

off and stockpiled on-site to be used later in the stabilized sub-

base and HMA shoulders. Existing PCC was removed and

crushed, often onsite with portable crushers or mobile crush-

ers, for use as the porous granular embankment (PGE) base

for the new roadway. The existing or remaining base-course

aggregate was then classifi ed as an embankment material and

was removed or thickened to the proposed subgrade elevation.

In areas that did not meet compaction or proof-rolling require-

ments, the subgrade was undercut and backfi lled with extra

quantities of the recycled PGE aggregate.

The common use of mobile milling and crushing equipment

allowed for the recycled and reprocessed asphalt and concrete

materials to be windrowed along the reconstructed right-of-way

to reduce or eliminate the need for truck transportation.

The new roadway was built with a new 12-in. subgrade aggre-

gate consisting of 9 in. of PGE and 3 in. of capping aggregate

that consisted of RAP grindings of a CA-6 gradation placed on

the compacted subgrade/embankment. A 3-in. HMA-stabilized

sub-base was used on top of the 12-in. subgrade aggregate. A

12-in. jointed plain PCC pavement with 15-ft joint spacing was

then paved over the HMA-stabilized sub-base. The Tollway used

a standard IDOT Class PV concrete mix for all pavements.

Ultimate compressive strength was achieved in three to

four days, utilizing a liquid curing compound. The pavement

Circle 805


was fi nished with variable-width tining slightly askew for bet-

ter control of tire noise. Pavement markings are recessed with

slow-cure multipolymer paint for improved refl ectivity and bet-

ter durability.

Double-lane slipform pavers, which measure 30 ft end to

end, were used for most of the mainline paving operations. Sin-

gle-lane slipform pavers were used mainly for paving ramps.

A standard paving train was used consisting of a spreader, a

paver and a tining machine.

Mainline shoulders were paved with bituminous asphalt uti-

lizing either a standard asphalt paver or a road widener. Both

machines used two rollers.

Work also included extensive amounts of noise wall and re-

construction of dozens of bridges. Bridge materials also fol-

lowed IDOT standards, pouring a 7½-in. concrete deck over

steel or precast prestressed concrete beams, with a seven-day

wet cure. Concrete conveyors or pumps were used to disperse

concrete onto the deck, followed by a bridge-deck fi nishing

machine. A series of work bridges were then used to apply

curing materials.

Trying not to disturbSome bridges, including Willow Road and Belvidere Road

(Illinois Rte. 120) also were lengthened to accommodate fu-

ture widening and reconstruction of local roads, and the Toll-

way worked closely with state and local agencies to develop

cost-sharing plans to minimize future traffic impacts.

As an example, the Willow Road Bridge was both lengthened

and widened to provide a six-lane pavement section with dual

left-turn lanes on Willow Road. This bridge expansion allowed

the reconstruction and widening of Willow Road from Sanders

Road to Landwehr Road, which not only helped reduce con-

gestion for the ramps to and from the Tri-State Tollway, but also

reduced travel times for local traffic.

Southbound construction was completed in 2008, and north-

bound work is expected to be completed by the end of 2009.

When construction began on the north end of the corridor in

2007, design engineers were busy at work designing plans for

2008 construction contracts. By performing construction while

designing work for the following year, the Tollway was able to

rebuild and widen the vast majority of the 45-mile stretch of

roadway in three years.

In order to rebuild and widen the roadway while maintaining

capacity, the Tollway adopted a maintenance of traffic (MOT)

plan that provided the same number of lanes during construc-

tion that were available before construction. As a result, lane

widths were reduced and traffic shifted into a counterfl ow con-

fi guration with express and local lanes. By shifting one lane

of traffic onto the other side of the road as an express lane,

the Tollway maintained three lanes of traffic during construc-

tion with work zones in place behind a temporary concrete

barrier wall.

The MOT plan reduced the impact of construction on drivers

while providing contractors the space they needed to work for

extended periods of time without frequent changes in the work

zone.

Additionally, the Tollway coordinated bridge reconstruction

by staggering construction schedules, thus providing alterna-

tive routes for the local drivers who relied upon the east-west

routes crossing over or under the Tri-State Tollway throughout

the region. Nearly all bridges were kept open during construc-

tion with staged traffic and reduced lanes. The Tollway coordi-

nated work with IDOT, Cook County, Lake County and local

government leaders to minimize the impact to local roads.

Farther to the north of the project, the Tollway continues to

work with the Wisconsin Department of Transportation on its

recently launched reconstruction plan for I-94 from Milwaukee

to the Illinois state line. In fact, the Tollway had extended its

widening project from Grand Avenue to Rte. 173 in part to coor-

dinate with Wisconsin’s I-94 reconstruction project. The Tollway

also is working with IDOT on its plans to widen the roadway

between Rte. 173 and the Wisconsin state line.

Kovacs is chief engineer and Gillen is materials manager at the Illinois Tollway, Downers Grove, Ill.



Southbound construction on the Tri-State was completed in 2008, and northbound work is expected to be completed by the end of 2009.


Kamil Kaloush, Krishna P. Biligiri, Philip White and Jay Golden

TT he 21st century is the century of urbanization. Along

with rapid urbanization, the century is observing

the biggest increase in the world’s population in hu-

man history. As of 2006, the world population had

reached 6.5 billion. Urbanization is quickly transitioning com-

munities from native vegetation to an engineered infrastruc-

ture. The result is an increased thermal-storage capacity of the

urban infrastructure from the use of the materials. This regional

impact is known as the urban heat island effect where urban

temperatures are elevated in comparison with their adjacent

rural surroundings.

Rapid global urbanization and explosive overall population

increases are generating high demand for new road networks.

Paved surfaces can comprise up to 45% of an urban region

fabric in the U.S. and are designed with energy-intensive prod-

ucts composed of either portland cement or petroleum-based

asphalt. Both of these products contribute to greenhouse-gas

emissions and climate change at both the urban and global

scales. There is a need for quantifying the impacts of pavement

materials on climate change.

Climate change can be defi ned as the variation in meteo-

rological patterns that can range from a local to a much larger

multinational scale. The Intergovernmental Panel on Climate

Change (IPCC) developed the Global Warming Potential

(GWP) protocol to compare the ability of each greenhouse

gas to trap heat in the atmosphere relative to another gas. The

GWP of a greenhouse gas is defi ned as the ratio of the time-

integrated radiative forcing from the instantaneous release of

1 kg of a trace substance relative to that of 1 kg of a refer-

ence gas. Direct radiative effects occur when the gas itself is a

greenhouse gas. The reference gas used is CO2, and therefore

GWP-weighted emissions are measured in teragrams of CO2

equivalent (Tg CO2 Eq.).

The total U.S. emissions have risen by 16.3% from 1990

to 2005. In 2005, total U.S. greenhouse-gas emissions were

7,260.4 Tg CO2 Eq. Two of the top three categories for CO

2

emissions are related to pavements. This includes asphalt as

well as cement manufacturing.

This article is aimed at presenting a methodology for road

designers and transportation officials to model the impact of

Latest research presents

methodology to prevent climate change

FIXINGair holes

Figure 1. Major elements needed to model the annual CO2 Eq. per length of roadway section.

Layer Thickness of Different Materials in Pavement System Roadway Width

Roadway Service Life

kg CO2 Eq./kg ofMaterial Production

kg CO2 Eq./kg ofMaterial Mixing

kg CO2 Eq./kg ofMaterial Transportation

Total Annual CO 2 Equivalent per Lengthof Roadway Section

Density of Materials in a Pavement System


different pavement types on climate change potentials in terms

of CO2-equivalent emissions. The process presented employs

variables that can be modifi ed by the designer to customize for

their specifi c road confi guration and materials type.

What’s the equivalent?Figure 1 shows some of the major elements needed to mod-

el the annual CO2 Eq. per length of roadway section. These

specifi c elements were selected because they provide a quan-

tifi able input to perform an analytical comparison. Other ele-

ments, such as rolling resistance, were found to be difficult and

challenging to consider in the modeling approach.

Table 1 provides a summary of components used to model

estimates of Kg CO2 Eq. produced per kilogram of the two

pavement types: portland cement concrete (PCC) and hot-mix

asphalt (HMA). The CO2 Eq. data came from high-quality in-

ventory output data of European origin. This data was used

because of its availability and considerable details. In addition,

it is noted that this assessment is limited to the fi rst life cycle of

the pavement. It does not take into consideration the resources

for emissions or lifetime created by secondary operations to

recycle the respective types of roads.

Figure 2 shows typical proportions of pavement materials

and their respective CO2 Eq. values per kg for production (Pn).

The transportation (Tp) values for these pavements, including

sand and gravel, are kept the same for simplicity. They were

calculated based on a 20-ton diesel truck (0.2821 Kg CO2 Eq. /

ton-km or 0.0002821 Kg CO2 Eq. / kg – km). Figure 3 shows the

mixing values (Mn), which were calculated utilizing CO2 Eq. for

the fuels utilized for each of the pavement structures. The CO2

Eq. impacts from mixing the concrete assume a 355-kilowatt

diesel truck running 36 minutes/batch, with 0.76 cu m/batch,

which is equivalent to 18,420 kg/batch. Based on interviews

Figure 3. Mixing values for PCC and HMA.

Figure 2. Kg CO2 Eq. values for the production of PCC and HMA.

GlobalWarming Gas

Portlandcement per Kg

Gravel per Kg Sand per Kg

Asphalt

Cement per Kg

Electricity,

US averagePer kW-hr

Transportper ton-km

Carbon dioxide, fossil 0.8048 0.0027 0.0023 0.3817 0.7155 0.2713

Carbon dioxide, fossil 0.0151 0.0001 0.0001 0.0410 0.0308 0.0084

Methane,fossil

0.0008 0 0 0.0010 0.0004 0.0011

Carbon monoxide, fossil

0 0 0 0.0023 0.0055 0.0012

Total Kg CO2 Eq. /kg

substance0.8207 0.0028 0.0025 0.4260 0.7468 0.2821

Table 1. A summary of components used to model estimates of Kg CO2 Eq. produced per kg of the two pavement types: portland cement concrete and hot-mix asphalt.

Figure 4. The total annual kg CO2 Eq./km with different pavement designs.

Total kg CO2 Eq./kg of Pavement Material during Production Process

Total kg CO2 Eq./kg of Pavement Material during Mixing Process

1.0

0.9

0.8

0.7

0.6

0.5

0.4

0.3

0.2

0.1

0.0

0.07

0.06

0.05

0.04

0.03PCC, 0.0065

HMA, 0.0663

0.02

0.01

0.00

Gravel (PCC) Sand (PCC) Portland Cement (PCC) Aggregate (HMA) Asphalt Cement (HMA)

% weight

40% 39%

13%

95%

5%0.0011% 0.001%

0.1034%

0.0025% 0.0213%

Kg CO2 Eq./kg

Transportation kg An. CO2 Bq./km

HMA 4", Base 6"

3,722 4,268 3,232 2,526 3,956

11,210 13,079 1,161 4,124 7,732

4,517 5,242 19,105 7,951 14,620

HMA 7", Base 10" PCC 10", Base 8" UTW 2", HMA 2", Base 6”

TW 5", HMA 5", Base 8”

30,000

25,000

20,000

15,000

10,000

5,000

0

Mixing kg An. CO2 Eq./km

Production An. CO2 Eq./km


with regional companies, the process-

ing data for a 2-ton asphalt/hr-capac-

ity system was determined to require

24.6 L of No. 2 fuel oil and 0.269 cu m

of natural gas per hour. The electric-

ity process inventory data source is a

North American average.

Table 2 summarizes the density and

CO2 equivalents for the production,

transportation and mixing stages for

both pavement types.

Pavement changeClimate change values are modeled

with IPCC 2007 CO2 characterization

values. Five pavement design scenar-

ios are created as shown in Table 3.

Note that these pavement designs are

presented for demonstration purpos-

es, and obviously they are the user’s

specifi c input. The thicknesses were

selected to represent common designs

practiced by transportation agencies.

Two designs are designated with mod-

erate traffic volume, whereas the other

three were designated as high traffic

volume designs. The estimated life for

each pavement was selected based

on practical pavement performance

experience of the authors (again, this

is a user input). UTW is an ultrathin

whitetopping PCC pavement; whereas

TW is a thin whitetopping PCC pave-

ment design.

A functional unit of 1/km-year and

a damage score unit of kg CO2 Eq./

km-year are used. Pavement width is

assumed to be two 12-ft-wide lanes

for all case scenarios. The distance

from material production site to ap-

plication site (Di) for aggregates was

assumed to be 25 km. The distance

from material production site to place-

ment site (Di) for HMA or PCC was

assumed to be 50 km. The values of

total CO2/km were calculated for each

Circle 802

Pavement CO2

equivalency valuesDn

Kg / m3

PnKg CO

2 Eq./kg

Tp

Kg CO2 Eq./kg - km

Mn

Kg CO2 Eq./kg

Sand 1600 0.0028 0.0002821 0

Gravel 1800 0.0025 0.0002821 0

Aggregate 1700 0.0026 0.0002821 0

PCC 2403 0.1055 0.0002821 0.00650

HMA 2275 0.0238 0.0002821 0.06630

Table 2. Density and total CO2 equivalents for production, transport and the mixing of pavement.

Upper layer Middle layer Aggregate Base Traffic

volume

Estimated

Life, yearsType inch meter Type inch meter inch meter

HMA 4 0.1016 6 0.1524 moderate 10

HMA 7 0.1778 10 0.2540 high 15

PCC 10 0.2540 8 0.2032 high 25

UTW 2 0.0508 HMA 2 0.0508 6 0.2032 moderate 15

TW 5 0.1270 HMA 5 0.1270 8 0.2032 high 20

Table 3. Alternative pavement design case studies.

pavement layer individually, top surface layer, middle layer (if

any) and a bottom layer, which is normally an aggregate base.

Figure 4 presents the results for the fi ve pavement design sce-

narios. The results show that this approach provides a distinc-

tion of the total annual kg CO2 Eq. for each lifecycle component

and pavement structure type.

Climate designRapid urbanization will continue to place increased demands

for transportation infrastructure requiring additional pavement

construction. This article introduced a process on how pave-

ment construction contributes to climate change in terms of an-

nual kg CO2 Eq. emissions. The methodology should prove to

be a useful tool for engineers and planners to examine the di-

rect CO2 emissions related to the selection of alternative pave-

ment designs. By adjusting the model parameters, users can

optimize a pavement design based on organizational needs as

well as regionally different climatic conditions, traffic volumes,

road maintenance and energy needs. •

Kaloush is an associate professor, Department of Civil, Environmental and Sustainable Engineering and director of the National Center of Excellence for SMART Innovations at Arizona State University. Biligiri is a research scientist, Department of Civil, Environmental and Sustainable Engineering at ASU. White is an assistant professor, Industrial Design Unit, College of Design Innovation and Sustainability at ASU. Golden is an associate pro-fessor, School of Sustainability and co-director of the National Center for SMART Innovations at ASU.

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Kimberly Kaylor

WW hile much has been written about the use of

stimulus funds and the state of our nation’s in-

frastructure, one project that has been in the

works for years was recently completed, high-

lighting the effectiveness of the concrete pavement restoration

(CPR) process.

In August, the last 22.4-lane-mile section on I-44—a high-

way that runs from the southern border of Texas to the Mis-

souri border in the northeast corner of the state—was fi nally

completed. This is the rehabilitated area between I-40 and I-35

in Oklahoma City, located 0.6 miles north of Reno Avenue and

extending north 2.9 miles to 0.5 miles north of Northwest 36th

Street. It is the culmination of fi ve projects on the roadway since

repairs began in 2004. Penhall Co. (Division 40) has served as

the prime contractor for all fi ve projects.

The highway is signifi cant because it connects three of Okla-

homa’s largest cities and is a primary corridor through the Mid-

west. The Oklahoma City section of the highway ranges from six

to eight lanes and overlaps I-35 for a short time. Approximately

125,000 to 135,000 vehicles travel this roadway each day.

According to Tom Hubbard, P.E., resident engineer, Okla-

homa Department of Transportation (ODOT), a physical

survey revealed severe panel damage and faulted pavement.

The road was in desperate need of repair as the transverse

joint faulting was in the ¼-in. to 3⁄8-in. range with isolated ½-in.

to 5⁄8-in. faults and variable ¼-in. to ¾-in. faulting at the longitu-

dinal joints. Pavement replacement areas were quantifi ed us-

ing a vehicle-mounted digital image collection system.

Given the high level of traffic and poor road conditions, a

fast-track yet long-term solution was needed. As such, ODOT

selected CPR because of previous success with this method.

By selecting CPR, the state was able to extend the life of

existing pavement and minimize disruption to the traveling

public at a fraction of the cost of doing an asphalt overlay or

total reconstruction.

CPR is a nonoverlay option used to repair areas of distress

in concrete pavement without changing its grade. This pre-

ventive procedure restores the pavement to a like-new condi-

tion and reduces the need for major and more costly repairs.

Furthermore, CPR also addresses the causes of pavement

distress, minimizing further deterioration. In contrast, cov-

ering the area with an asphalt overlay does not correct the

cause, and the problem will eventually appear again, resulting

in a much more expensive solution. In fact, reports from the

Concrete pavement restoration helps cure faulted pavement on I-44

faultFixing


Transportation Research Board state that for every dollar in-

vested in appropriately timed preventive pavement mainte-

nance, $3 to $4 in future rehabilitation costs are saved.

Benefi ts of CPR include:

It addresses the causes of pavement distress, minimizing •

further deterioration;

It costs less and lasts longer. The California Department of •

Transportation (Caltrans) has shown that diamond grinding,

when used as a CPR strategy, typically lasts 16 to 17 years;

It is quicker and causes less traffic disruption. Because CPR •

maintains the existing grade, features such as curbs, gut-

ters, bridge clearances, approach slabs and roadside appur-

tenances do not need adjustment. In addition, CPR repairs

only those areas that need improvement, such as the driving

lane or the keel section of a runway;

It preserves the safety of concrete pavement. Concrete does •

not ravel, washboard or shove. These defects can cause seri-

ous safety problems for asphalt pavements at intersections or

other locations where traffic is starting, stopping and turning;

It preserves the environmental benefi ts of concrete pave-•

ment. Concrete’s light color reduces the number of street-

lights needed to achieve the same illumination on a dark as-

phalt pavement. The light surface also can keep urban areas

cool. Additionally, the hard concrete surface makes vehicles

more fuel efficient. Given the fact that concrete pavements do

not defl ect like asphalt pavements, studies have shown that

they can reduce truck fuel consumption signifi cantly; and

It can be used to repair a concrete pavement that has been •

previously overlaid with asphalt.

The tricky approachIn 2004, ODOT initiated repairs for all eastbound and west-

bound lanes, including auxiliary and ramp lanes, on I-44,

broken into the following fi ve phases:

In 2004, from the junction of S.H. 74 extending east to the •

Burlington Northern Santa Fe Railroad, just west of I-235;

In 2005, from west of Western Avenue, extending east to Lin-•

coln Blvd.;

In 2007, beginning at Lincoln Blvd., extending east to I-35; •

In 2008, beginning at the Oklahoma River, extending north •

to the Burlington Northern Santa Fe Bridge; and

In 2009, repair of four lanes, eastbound and westbound, be-•

ginning at the Burlington Northern Santa Fe Bridge to the

Junction of S.H. 74.

Dowel-bar retrofi t (DBR), diamond grinding, joint sealing,

selective panel replacement and base repair were used on

the project for all lanes in both directions. DBR restores load

transfer across the pavement joints to prevent future rough-

ness from occurring, and then the entire surface is diamond

ground, which produces a smooth and quiet ride. According to

Hubbard, DBR and diamond-grinding projects are extremely

effective in extending pavement service lives.

“In the past decade, many dowel-bar retrofi t and diamond-

grinding projects have been completed in the Oklahoma City

metro area. In each case, user costs were minimized by per-

forming the work during nighttime hours. The cost-effective na-

ture and minimized user costs are key in the success of pave-

ment restoration,” said Hubbard.

According to Mike Miller, the Penhall superintendent re-

sponsible for the bridge approach work, the 10th Street bridge

portion of the project, which consisted of 24 bridge approach

panels, presented many challenges. Specifi cally, it was diffi-

cult to remove the approach, perform subgrade repair, as well

as place the double-mat rebar reinforcement and high-early-

strength concrete during a single night shift during live traffic

even though it was diverted.

“Although we had done work like this before, we were very

concerned because we had never completed it in a single

night,” said Miller. “We used all the tools in our toolbox. We

had the best crew members, as well as extra equipment and

In 2004, ODOT initiated repairs for all eastbound and westbound lanes, including auxiliary and ramp lanes, on I-44. The work was broken down into fi ve phases and was com-pleted in 2009. The total value of this fi nal phase of the project was approximately $2.9 million, and the repair is expected to offer another 15 years of service life.


materials staged in case we had any problems. The removal

went well, but we learned some lessons regarding the steel

placement. The key to our success was being able to batch

our own ready-mix. With the help of General Resource Tech-

nology, we were able to

manufacture and place

a high-strength con-

crete that kept us on

schedule.”

Safety also was a

daily concern. Accord-

ing to Miller, Action

Safety Supply did an

outstanding job mov-

ing the traveling public

though such a compli-

cated area. The com-

pany had crews on the

project during all hours

of the work. The work

area extended from

three to fi ve lanes with

right-hand and left-

hand on and off ramps.

“Action Safety Supply

played a critical part in

the success of the over-

all project,” said Miller.

Brent Burwell, execu-

tive director of the Okla-

homa/Arkansas Chapter of the American Concrete Pavement

Association, noted that it was excellent to see this section of

I-44 being restored using CPR instead of a costly asphalt over-

lay method.

“The original pavement, built in 1976, has served the public

well over the years, and with the improvements made to the

roadway through this project, we may see another decade or two

of service,” said Burwell. “The concrete pavement preservation

techniques used in this project do more than just cover the prob-

lem for a few years. Combined with the long life of the original

pavement, the work performed by the contractor, Penhall Co., will

give the taxpayers of Oklahoma a great value for their money.”

The total value of this fi nal phase of the project was approxi-

mately $2.9 million, and the repair is expected to offer another

15 years of service life. The total cost of all fi ve projects since

2004 was $11.3 million.

Pete Lewis, Penhall’s

regional manager re-

sponsible for its CPR

Division, said that his

fi rm has been involved

with the CPR industry

through its Highway

Services Division in

Rogers, Minn., for ap-

proximately 20 years.

He noted that they were

pleased when ODOT

started to ask ques-

tions regarding CPR.

“We are pleased to

have been a part of the

reconstruction of the

I-44 corridor in Okla-

homa City,” said Lewis.

“ODOT has always had

the best interest of the

traveling public and the

taxpayers of Oklahoma

in mind during this com-

plicated process. It was

with everyone’s hard work and honest considerations that CPR

had a chance to prove its value. CPR has proven that concrete

pavements are renewable.”

Kaylor is president of Constructive Communications Inc., Dublin, Ohio.



CPR techniques include:Soil stabilization to support concrete slabs; •

Full-depth repairs that include removing a portion of the existing slab and replacing it with new concrete; •

Partial-depth repairs to correct surface distress and joint-crack deterioration in the upper third of the concrete slab; •

Dowel-bar retrofi t (DBR) that consists of cutting slots in the pavement across the joint or crack, cleaning the slots, placing • the dowel bars and backfi lling the slots with new concrete. This provides load transfer at the joints, allowing for a longer life for plain-jointed concrete pavements;

Cross-stitching longitudinal cracks or joints to add reinforcing steel to hold the crack together tightly; •

Diamond grinding, which removes faulting, slab warping, studded tire wear and unevenness resulting from patches. • Diamond grinding also reduces noise and provides proper skid numbers to ensure safe travel; and

Joint and crack resealing, which minimizes surface water and incompressible material infi ltration into the joint system, • minimizing long-term maintenance costs.

On the I-44 project user costs were minimized by performing the work during nighttime hours.The cost-effective nature and minimized user costs are key in the success of pavement restoration.



AAunique project in Missouri is currently in its sec-

ond phase on I-64 through St. Louis. The design-

build project, the city’s fi rst, is a complete replace-

ment of approximately 10 miles of the interstate

right through the heart of the city. One-half of the 10 miles is

completely shut down to traffic while work takes place. The un-

precedented move is taking years off the completion date and

creating a safer environment for the construction workers.

The project is being built by a consortium called Gateway

Contractors, which involves contractors Granite Construction,

Fred Weber Inc. and Millstone Bangert Inc. The two-year proj-

ect involves 200,000 cu yd of concrete. All of the concrete will

be slipformed.

Fred Weber and Millstone Bangert have brought their fl eet of

equipment onto the project. That fl eet includes three GOMACO

9500 trimmer/placers, an RTP-500 placer, four Commander III

four-tracks and a GHP-2800 paver. It is a lot of equipment, but the

variety of applications the equipment is slipforming is impressive.

The Commander IIIs are slipforming shoulders, medians,

variable-width ramps, inside median barrier walls, outside bar-

rier walls, retaining walls, roundabouts, bridge parapets, truck

lanes, half-shaped barrier walls against mechanically stabilized

earth (MSE) walls and moment slabs for the sound wall.

10-12 on the smoothness scaleAll of the material on the project was recycled. The con-

crete was crushed and used again for the base material. The

base for the I-64 project consists of 10 in. of 6-in.-minus rock,

capped with 2 in. of Type 5 rock. The top layer is trimmed to the

accurate, fi nal grade with a GOMACO 9500 with an 18-ft-wide

trimmerhead.

Millstone Bangert is responsible for all of the mainline paving

on the project and is using its four-track GHP-2800 paver. Proj-

ect smoothness specifi cations require a reading of less than

30, and Millstone Bangert is consistently running between 10

and 12 on the zero-blanking band. Smoothness, according to

Ron Dibler, Millstone Bangert’s paving superintendent, begins

with the base.

“Good ride is a process that begins from the ground up,”

Dibler said. “You have to have good string, consistent mix and

try to keep the paver moving with minimum stops. Most impor-

tant, though, is a good, solid trimmed base to pave on and run

the paver’s tracks.”

Each paving pass is 9 or 10 in. thick and 25 ft wide. They are

building four new lanes of interstate for both the eastbound and

westbound sides. Paving production averages between 2,500

and 3,000 cu yd per day.

URBAN OUTFITTINGContractor speeds through heart of St. Louis behind design-build schedule

All of the concrete for the project is being supplied by two

onsite batch plants. Concrete is delivered to the paving site by

tandem-axle dump trucks. The concrete is a Missouri Depart-

ment of Transportation (MoDOT)-approved mix with an aver-

age slump of 1.5 in.

Putting up wallsThe profi les for the inside and outside barrier walls are very

similar, but the outside barrier has sound wall mounted to the

top of it. A Commander III is used to slipform a moment slab

with a rebar grid. The steel for the wall is tied to the rebar grid

in the moment slab. With the steel in place, the spacing for the

sound wall is meticulously plotted, and the anchoring bolts for

each post are carefully set.

“The sound wall posts have to be put in the exact location,

because each panel is made to fi t a certain area,” Dibler said.

“After the cages are built, we dry run the steel to make sure

everything is going to work and it’s all set to the right height.”

The concrete trucks dump their loads into an RTP-500,

which then feeds the belt on the Commander III. The cen-

tral mix concrete, according to Dibler, gives their concrete

more consistency and allows them to run a drier mix for their

barrier work.

Behind the Commander III, workers have to locate the an-

choring bolts for the sound wall, dig them out and expose them

so the posts can be installed after the concrete has cured.

A 9500 placer feeds another four-track Commander III as it

slipforms the variable-height center median barrier. The height

of the wall varies from 4 to 7.25 ft.

The non-variable-height barrier has 10 longitudinal bars fed

into the front of the mold for wall reinforcement. The variable-

height barrier is slipformed over a steel cage in the lower half

of the wall. They are inserting six longitudinal bars into the front

of the mold for the top section of the wall.

The consortium engineered a cost-saving measure on the

project by stacking two slipformed walls on top of each other

instead of putting in MSE wall. The fi rst retaining wall varies in

height between 3 and 6 ft. Two rebars are hydraulically inserted

vertically into the 24-in.-wide top of the wall, and vibration is

applied to the rebar during insertion. The wall is allowed to

cure and then backfi lled. The roadway is brought up to grade,

and then another section of wall is slipformed on top of the

existing wall.

“The slipformed retaining wall replaces MSE walls shorter

than 9 ft in areas that would retain dirt,” Dibler explained. “Rath-

er than building a costly MSE wall, we were able to slipform

retaining walls.”

All of the shoulders and medians on the project are slip-

formed with a side-mounted mold on the Commander III. Me-

dians are slipformed 6 ft wide. Shoulders vary from 4 to 10

ft, or 8.5 ft if there is a barrier wall on it. Zero-clearance pav-

ing against the MSE wall was accomplished after modifying

the mold.

“We had an idea of moving the sideform cylinders and

mounting structure from the outside of the mold to the inside of

the mold and minimizing the thickness of the sideform,” Dibler

said. “We were able to get that down to about 2 in., which

allows us to slipform closer to the walls, and that’s been a big

help on this job.”

Width changes on the ramps include transitions from 15 ft

down to 12 ft wide and 18 ft down to 12 ft wide. The transi-

tions are made on the go, with no need to stop and adjust the

paver width.

Another cost-saving measure on the project included build-

ing two roundabouts instead of entrance and exit ramps. The

20-ft-wide, 8-in.-thick roundabouts, with integral curb on one

side, had to be built around a 45-ft radius. Fred Weber decided

to pave the fi rst roundabout in two separate pours. The fi rst

was 10 ft wide and the second was the same width with a 3-in.

mountable curb.

“The tight radius intimidated us a bit on the fi rst roundabout,”

Jackson said. “The second one, though, we decided to pour

the full 20 ft with the curb on it. It worked out just fi ne, and we

accomplished it all in one pour, instead of two.”

To fi nish out the roundabout, a lane was slipformed inside

of its radius. The lane, which is used to assist trucks through

the roundabout, was 9 in. thick and 10 ft wide with a 6-in.

vertical curb.

The I-64 project is scheduled to have traffic back on the fi n-

ished second phase by the end of this year. It is a deadline the

consortium is confi dent they will make.

Information for this article provided by GOMACO Corp.




Another cost-saving measure on the project included building two roundabouts instead of entrance and exit ramps. The 20-ft-wide, 8-in.-thick roundabouts, with integral curb on one side, had to be built around a 45-ft radius.

Hig

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