Effect of Wide-Base Super Single Tires on Pavements

David Huft, SDDOT Research Program ManagerAASHTO Research Advisory Committee Meeting

Madison, WI July 22, 2014

Connecting South Dakota and the Nation

SD2012-01 Effect of Wide-Base Super-Single Tires on Pavements• Suggested by SD

Trucking Association• Hoped to lift 500

lb/in restriction on 445/455 mm tires

• 5-month project• Work by Hao Wang

From Priest & Trimm, TRR 1949

Wide-Base Tire Characteristics

• Introduced to North America in 1982 to replace dual tires

• Design for high-speed long-distance carrier

• Reduced fuel consumption

• Reduced tire recycling• Increased payload• Better ride comfort

and vehicle handling

1980 198220002002

2000

385 425 445/455 495

Dual/ 275

Early & Recent Wide-Base TiresEarly Generation• 385/65R22.5,

425/65R22.5)• High inflation

pressure (790-890kPa)• Small contact area• High contact stress• High damage ratios

• 1.5-2.0 for rutting• 2.0-4.0 for fatigue

cracking

New Generation• 445/50R22.5, 455/55R22.5• New crown architecture• 15-18% wider than 1st gen• Reduced tire pressure• Damage ratios vary by:

• pavement structure• damage type• climate condition

(Virginia Smart Road 2000; Europe COST334 2001; Canada 2004; NCAT 2006; ILDOT 2008; FLDOT 2010)

Problem Statement

• In South Dakota, wide-base tires may be generally substituted for standard duals, but the legally allowed weight on single axles is reduced• 17,500 lb for 445mm tires, 18,000 lb for 455 mm tires• 20,000 lb for dual-tire configurations

• Previous studies involving laboratory tests, field tests, and modeling have generated mixed results

• It was unclear whether results are applicable to the full range of road surfaces (including unpaved) that exist on state and local highways in South Dakota

Objectives• Based on others’ research, assess effects of allowing

20,000 pound loads on single axles equipped with 445mm and 455mm wide-base tires on state and local roads in South Dakota

• Assess need for additional research involving physical testing or modeling

Major Research Tasks• Extensive Literature

Review• State Survey and

Interview• Select Most Pertinent

Studies

• Calculate Damage Ratios

• Assess Impact of Policy Change

• Assess Additional Research Needs

Selection of Most Pertinent Studies

Studies on wide-base tires Similar Pavement Design in South Dakota

Quebec Ministry of Transportation (Pascale et al. 2004) TonS

(Thin on Strong: 2 to 5 in. ACP on > 8 in. granular base)UTC/Nextrans Study (Al-Qadi and Wang

2010; Wang and Al-Qadi 2011)

NCAT Study (Priest and Timm, 2006)THK

(Thick: 5 to 10 in. ACP w/ granular base)

Ontario Ministry of Transportation (Ponniah et al. 2006)

Florida DOT Study (Greene et al. 2010)

Illinois DOT Study (Al-Qadi and Wang 2009)

FD(full-depth: > 10 in. ACP w/no

granular base)

Tire-PavementContact Area and Stress

0

500

1000

1500

0 1 2 3 4 5 6 7 8 9 10 11Tire ribs

Ver

tical

Con

tact

Str

ess

(kP

a)

Dual-tire Assembly

Wide-base 455

0

100

200

300

400

0 1 2 3 4 5 6 7 8 9 10 11Tire ribs

Tra

nsve

rse

Con

tact

Str

ess

(kP

a)

Dual-tire Assembly

Wide-base 455

(Wang and Al-Qadi 2009; 2011)

Damage Ratioson Thin & Thick Asphalt Pavement

Distress Thin Asphalt Thick Asphalt

Fatigue Cracking 1.68-2.82 0.86-1.26

Top-Down Cracking N/A 0.16-0.67

Primary Rutting 1.35-1.77 1.05-1.27*

Subgrade Rutting 1.31-2.35 N/A

ReferencesWang and Al-Qadi, 2011

Pascale et al. 2004Greene et al. 2010Ponniah et al. 2006

Combined Damage Ratios

Pavement Type

Wide-base 455 vs. Dual tires

Wide-base 445 vs. Dual tires

Range Average Range Average

Full-depth (FD) 0.85-1.32 1.08 NA NA

Thick asphalt (THK) 0.69-1.07 0.88 0.76-1.41 1.08

Thin asphalt on strong base

(TonS)1.45-2.31 1.88 NA NA

SB154: Allows 445/455 mm Tireson Major SD Highways

and “any locally designated highway within the corporate limits of any municipality

adjacent to the Interstate highway system”

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Future Work

• Analyze impact on fullrange of road surfaces(including unpaved) in SD

• Quantify possible increase of life-cycle agency cost by allowing equal load limit on wide-base single tires and dual tires on other state and local roads

• Consider three important contributing factors to pavement damage ignored in previous studies: unbalanced loads between dual tires, wheelpath wandering, and dynamic loading

Keys to Project Success

• Active support of SD trucking industry• Political urgency• Multi-disciplinary technical panel• Relevant research by done others• Availability of experienced researcher

Questions?

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Please contactDavid HuftSDDOT Research Program Manager605.773.3358dave.huft@state.sd.us