Summer 2009

Connecticut Begins to Usethe Notched Wedge Joint

Longitudinal joints in asphalt pavements are formed between individualpasses of the paver. Ideally, this longitudinal joint is as durable as the rest ofthe asphalt pavement mat and will have a life span comparable to the rest ofthe pavement. The most common longitudinal joint failure occurs from acrack forming in the longitudinal joint, this issometimes referred to as the longitudinal joint“opening up”. All longitudinal joints willeventually crack, but the severity and widthof the cracking dictates whether or not stan-dard pavement maintenance activities such ascrack sealing can be effective in preventingfurther pavement degradation. In some cases,the crack in the longitudinal joint will becomeso large that it becomes a safety hazard, as bicycle and motorcycle wheels canfit into and become wedged in the crack. Even if the crack does not becomelarge enough to present a safety hazard, the crack will allow water to infiltrateinto the pavement structure and ultimately damage it.One of the major causes of asphalt pavement cracking, along with longi-

tudinal failure, is the thermal cycling that all pavements experience virtuallyeveryday. These thermal cycles will slightly increase the overall thickness of

see Notched Wedge on page 3

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Connecticut Begins to Use the 1Notched Wedge Joint

Work Zone Safety Training 2for Law Enforcement

From the T2 Center 2Resource Library

FHWA Urges Road Agencies 4to Consider “Top Nine”Life-Saving Strategies

2008 HMA Paving Awards 6

Technology Transfer Center 2009 6Fall Calendar

2009 Technology Transfer Expo 7

Technology Transfer CenterRequest Form 8

In this Issue

class to be veryhelpful and theinformation to beuseful for their jobs.

We will offer additional sessions of thistraining in the future.For more information about this

training, visit our website at:www.t2center.uconn.edu or contactMary McCarthy at (860) 486-0377This year in Connecticut, several billswere proposed to our state legislature thataddress improving work zone safety andPublic Act 09-187 (S.B. 1081) Section47 was passed and encourages the StatePolice, the Post Officer Standards andTraining Council, and each municipalpolice department to provide work zonesafety training for law enforcement ineach basic and review police trainingprogram.For more details about the new bill,

please visit: www.cga.ct.gov/2009/BA/2009SB-01081-R01-BA.htm

Many local municipal agencies andprivate contractors enlist the assis-tance of local law enforcement tomanage traffic in and around their workzones and to protect the exposed work-ers. State troopers are also regularly usedby the Department of Transportation inwork zones on our highways. This is ahuge responsibility for our law enforce-ment officers and it is very importantthat they receive proper work zone safetytraining. Recognizing proper work zonepractices will help keep our workers andofficers safe.We at the Technology Transfer Center

have long been committed to trainingour State and Local highway employeeson the principles of work zone safety andhave recently added a training specificallyaddressing the role of law enforcement inthe work zone.We held our first two sessions of

Safe and Effective Use of ConnecticutLaw Enforcement in Work Zones inearly May and received very positivefeedback from our participants. Evalua-tions show that participants found the

This publication is published by theConnecticut Transportation InstituteTechnology Transfer Center

Phone: (860) 486-5400Fax: (860) 486-2399Web: www.t2center.uconn.edu

Supported through a cooperative effortof the Connecticut Department ofTransportation and the Federal HighwayAdministration’s Local TechnicalAssistance Program (LTAP) to provideinformation on the latest transportationtechnology to Connecticut’s state andlocal government officials.

Donna SheaPROGRAM DIRECTORshea@engr.uconn.edu

Mary McCarthyTRAINING SPECIALISTmary@engr.uconn.edu

Shelly DesjardinPROGRAM ASSISTANTshelly@engr.uconn.edu

Vivian CastelliPROGRAM AIDEvivianc@engr.uconn.edu. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

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Work Zone Safety Trainingfor Law Enforcement

State and local transportation and publicworks agencies within Connecticutmay request the following resourcesby calling 860-486-5400 or using theonline information request form atwww.t2center.uconn.edu/resourcerequest.php.

Protecting Our Pavements:PREVENTIVE MaintenanceFederal Highway Administration andFoundation for Pavement Preservation,1998, VHS, 15 minutesPresents highway agency decision-

makers with information about the needfor, and benefits of, policies and fundingstrategies in support of preventivemaintenance programs.

Preventive Maintenance ProjectSelection: Right Road, Right Treatment,Right TimeFederal Highway Administration andFoundation for Pavement Preservation,2000, VHS, 30 minutesProvides state and local maintenance

supervisors and highway managers withinformation on selecting the right roadfor the right treatment at the right time.Addresses various pavement groups,environmental effects on pavements,and pavement condition measurements,and presents examples of preventivemaintenance treatments.

From the T2 Center Resource Library

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the pavement; as the asphalt binder ex-pands, it warms and pushes the aggregatesapart slightly. Then as it cools, it is unable topull the aggregates back together as tightlyas they were when the material was placed.As there is only so much asphalt pavementin a road, in order to increase the thickness,the dimensions in the length and widthmust decrease. A prime example of this isthe gap that typically forms between theasphalt in a driveway and a garage floor.More than likely, the asphalt, at the timeof construction, was flush with the garagefloor and over time, it has slowly pulledback. Another place where thisphenomenon is quiteevident is in large parkinglots where there arewide cracks. In many

situations, if you were able to somehowpush the two sides back together, theywould fit back together like two pieces ofa jigsaw puzzle. In these cases, there is nomaterial missing from either side of thecrack, so the overall thickness of thepavement had to increase slightly to formthe crack.One of the keys to ensuring good

performance of longitudinal joints is

achieving a high degree of compaction atthe joint. Achieving a high degree ofcompaction provides adequate material sothat as the thermal cycling begins to slowlychange the pavement’s dimensions, thereis adequate material to minimize theamount that the longitudinal joint“opens up”.The most common method

used to make these longitudinaljoints in Connecticut has beenthe standard butt joint. A longitu-dinal butt joint typically consists oftwo faces that are essentially vertical thatare placed along side of each other from twoseparate paver passes. As indicated above,experience has shown that these jointsmay not last nearly as long as the restof the pavement and may present

safety concerns as well as potential damageto the entire pavement structure.For the 2009 construction season, the

Connecticut Department of Transportation(CTDOT) is allowing the use of a notchedwedge joint to create longitudinal joints inasphalt pavements. There are as manydifferent names for the notched wedge jointas there are different variations of thejoint construction technique.

They all work on the same basic principal—instead of creating two nearly vertical facesfor the longitudinal joint as is done with thebutt joint, during the placement of the first

paver pass, a taper is created thatextends eight to twelve inchesfrom the end of the paverpass. The CTDOT specifica-tion requires a small com-pactor to follow the paverand compact the taper.Many contractors have optedto attach a plate compactor

directly to the paver. Compactingthe taper helps to prevent traffic fromtearing the taper apart and it minimizes theamount of loose aggregate on the roadway.The second paver pass then matches upwith the first pass, covering the taper.

Now instead of two vertical faces compris-ing the longitudinal joint, the interfacebetween the two paver passes involves aconsiderable amount of material; making itmuch more difficult for the longitudinaljoint to open up.Research conducted by the Connecticut

Advanced Pavement Lab at CTI indicatesthat the overall average density of longitudi-nal joints constructed using the notchedwedge joint is higher than the densi-ties achieved using the butt jointconstruction. This results in a moredurable longitudinal joint. This isnot to say that the notched wedgejoint is a cure-all that will eliminatelongitudinal joint failures, but it

should be looked upon as a viableoption to achieve the best possible product.In short, to ensure the best possibleperformance of any longitudinal joint,it is important to make sure that the bestconstruction practices are followed.

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Notched Wedge continued

continued on page 5

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Technology Transfer Center 3

FHWA Urges Road Agenciesto Consider “Top Nine”Life-Saving StrategiesThe FHWA Safety Program urges State andlocal roadway officials to consider imple-mentation of nine safety countermeasuresthat show great potential to reduce highwayfatalities and injuries. As State highwayagencies develop plans to address the safetychallenges identified in their strategic high-way safety plans, they are urged to considerthe benefits of investments in these provenroadway safety tools and techniques.

ROAD SAFETY AUDITS

A road safety audit (RSA) is a formal safetyperformance examination of an existingor future road or intersection. Audit teamsare independent and multidisciplinary.The team reports on potential road safetyissues and identifies opportunities toimprove safety for all road users.

RUMBLE STRIPSAND RUMBLE STRIPES

Rumble strips are raised or grooved patternson the roadway that provide both an audiblewarning (rumbling sound) and a physicalvibration to alert drivers that they areleaving the driving lane. They may beinstalled on the roadway shoulder or on thecenterline of undivided highways. Rumblestripes are rumble strips that are placed atthe centerline or edgeline.

MEDIAN BARRIERS

Median barriers are longitudinal barriersused to separate opposing traffic on adivided highway. They are designed toredirect vehicles striking either side of thebarrier. Median barriers can significantlyreduce the number of cross-mediancrashes and the overall severity ofmedian-related crashes.

SAFETY EDGE

The Safety Edge asphalt paving techniqueminimizes vertical drop-off safety hazards.A Safety Edge shape is created by fittingresurfacing equipment with a device thatextrudes and compacts the shape of thepavement edge at a specific angle as thepaver passes. This mitigates shoulder pave-ment edge drop-offs immediately duringthe construction process and over the lifeof the pavement. Because the techniqueinvolves only a slight modification of pavingequipment, it has a minimal impact onproject cost. Improved compaction of thepavement near the edge is an additionalbenefit of the Safety Edge.

ROUNDABOUTS

A roundabout is a circular intersectionwhere entering traffic yields to vehicles on

the circulatoryroadway.Roundaboutsare designedto channeltraffic atthe entranceand providecollision deflectionaround a center island. Modern round-abouts are geometrically designed to reducespeeds and deflect collision forces, whichsubstantially improves safety, while provid-ing excellent operational performance atthe intersection.

LEFT- AND RIGHT-TURN LANEAT STOP-CONTROLLEDINTERSECTIONS

Left-turn lanes are auxiliary lanes for storageor speed change of left-turning vehicles.Left-turn lanes reduce the likelihood ofintersection crashes. They also make turningeasier for drivers and improve the intersec-tion’s operational efficiency. Right-turnlanes provide a separation at intersectionapproaches between right-turning trafficand adjacent through-traffic. This reducesconflicts and improves intersection safety.

YELLOW CHANGE INTERVALS

Yellow signal lights that are not timedappropriately are a safety hazard. Yellowchange intervals that are not consistent withnormal operating speeds create a “dilemmazone” in which drivers can neither stopsafely, nor reach the intersection before thesignal turns red.

MEDIANS AND PEDESTRIANREFUGE AREAS IN URBANAND SUBURBAN AREAS

Medians reduce traffic conflicts and increasesafety by providing a buffer area betweenopposing lanes of traffic. Medians can beopen (pavement markings only), or channel-ized (raised medians or islands) to separatevarious road users. Pedestrian RefugeAreas—also known as crossing islands,center islands, refuge islands, pedestrian

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Technology Transfer Center 5

islands, or median slow points—are raisedislands placed in the street to separatecrossing pedestrians from vehicles.

WALKWAYS

Appropriately designed walkways increasesafety for all road users. Types of walkwaysinclude:

• Pedestrian Walkway (Walkway) –A continuous way designated forpedestrians and separated from motorvehicle traffic by a space or barrier.

• Shared Use Path – A bikeway orpedestrian walkway physically separafrom motor vehicle traffic by an openspace or barrier, either within a highwayright-of-way, or within an independentright-of-way. Shared use paths may alsobe used by pedestrians, skaters, wheelchair users, joggers, and other non-motorized users. Shared use paths alsoare referred to as “trails” or “multiple-usetrails.”

• Sidewalks – Walkways that are pavedand separated from the street, generallyby curb and gutter.

• Roadway Shoulder – In rural orsuburban areas where sidewalks andpathways are not feasible, gravel orpaved highway shoulders provide a saferarea for pedestrians to walk next to theroadway.

The notched wedge joint hasadditional advantages as well. One ofthese is that traffic can safely traversebetween the freshly- paved lane and theexisting pavement. This does still requireproper signage to ensure the motoringpublic is aware that there is unevenpavement. With traffic being able totraverse on and off of the fresh pave-ment, it is not always necessary to pavecurb-to-curb each day. One note ofcaution with regard to not pavingcurb-to-curb is that the freshly-placedpavement must extend to the crown ofthe road to prevent holding water in theevent of rain—rainwater retention wouldcreate unsafe conditions. Not having toswitch the traffic control pattern andback the paving train up increases theefficiency of the paving operation. Thisreduces the overall duration of the pavingoperation which, in turn, minimizesdisruption to the public. In addition,not having to switch the traffic patternreduces the exposure of constructionworkers.The notched wedge joint is not

appropriate for lift thicknesses less than1.5 inches. For applications less than1.5 inches, it is not possible to form thenotch and the taper as the lift thicknessis not sufficient. The notched wedgejoint may also not be appropriate forareas with excessive amounts of turningtraffic, such as in heavy retail areas.Large amounts of turning traffic havea tendency to severely damage thepartial joint.The notched wedge joint has the

potential to improve the performanceof longitudinal joints in asphaltpavements. In order to realize thisimproved performance, it is importantto follow best construction practices—if a joint is constructed with poorworkmanship, it does not matter whattechnique is used to construct it—its durability will be compromised.

Notched Wedge continued

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TechnologyTransfer Center2009 FallCalendar

September

1 Chainsaw Safety & OperationsDuring Storm Clean-Up, Willington

3 Chainsaw Safety & OperationsDuring Storm Clean-Up, Willington

16 Technology Transfer Expo –University of Connecticut, Storrs

29 Pavement Preservation Management,Manchester

30 Pavement Preservation Management,Glastonbury

October

1 Pavement Preservation Techniques:Asphalt & Chip Seals, Monroe

7 Mechanic’s Roundtable Discussionon the Effect of Winter Operationson Municipal Fleets

20-21 Front-end Loader – Train the Trainer21 Fleet Safety Best Practices,

Burlington22 Fleet Safety Best Practices, Storrs29 Technology Transfer Center

Graduation Ceremony, Storrs

For updates on our trainingprograms, visit us at:www.t2center.uconn.edu

2008 HMA Paving Awards

At the 51st Annual Paving Conference hosted on April 8, 2009 by the CAAPA(Connecticut Asphalt & Aggregate Producer’s Association), the CCIA(Connecticut Construction Industries Association) and the ConnecticutDepartment of Transportation, the following awards were presented:

To recognize a quality HMA Pavement placed on a municipal roadway,the following team exemplified the highest standards of paving excellence.

Location: Old Whitfield Street, Town of GuilfordPrime Contractor: American IndustriesPaving Contractor: American IndustriesInspection Agency: Town of Guilford

To recognize a quality HMA Pavement placed on a limited access roadway,the following team exemplified the highest standards of paving excellence.

Location: Route 9-Newington, New Britain, FarmingtonPrime Contractor: Tilcon Connecticut, Inc.Paving Contractor: Tilcon Connecticut, Inc.Milling Contractor: Costello Industries, Inc.Inspection Agency: ConnDOT – District 1, Maintenance

To recognize a quality HMA Pavement placed on an unlimited access roadway,the following team exemplified the highest standards of paving excellence.

Location: Route 190 – SomersPrime Contractor: Galasso Materials, LLCPaving Contractor: Galasso Materials, LLCMilling Contractor: Costello Industries, Inc.Inspection Agency: ConnDOT – District 1, Maintenance

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Technology Transfer Center 7

UNIVERSITY OF CONNECTICUTTECHNOLOGY TRANSFER CENTER270 MIDDLE TURNPIKE, UNIT 5202STORRS, CT 06269-5202

NON-PROFIT ORG.U.S. POSTAGE

PAIDSTORRS, CT

PERMIT NO.3

Technology Transfer Center Request Form

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Please fax a copy of this form to (860) 486-2399 or mail to:

University of ConnecticutTechnology Transfer Center270 Middle Turnpike, Unit 5202Storrs, CT 06269-5202

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