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Title:

Factors Affecting the IRI of Asphalt Overlays

Accession Number:

01514876

Record Type:

Component

Availability:

Transportation Research Board Business Office

500 Fifth Street, NW
Washington, DC 20001 United States

Abstract:

Smooth roads provide a more comfortable ride and increased fuel efficiency for the traveling public and can also benefit state highway agencies by increasing the pavement service life. Many agencies ensure a smooth pavement is built by applying quality assurance rideability specifications for asphalt pavements with incentive or disincentive pay adjustments to new construction, rehabilitation, and maintenance overlay projects using the International Roughness Index (IRI). This paper considers some of the key project factors that can influence the IRI of construction or maintenance project. Data from South Carolina Department of Transportation projects completed during 2010 and 2011 in which rideability testing was applied was used to evaluate as the basis for this evaluation. It was found that a greater number of asphalt lifts placed related to an improved IRI value for the project for up to 3-lifts. The pre-overlay rideability proved to be an important factor in the rideability of 1-lift overlay projects (rougher pavements initially are more likely to be rougher after overlay) exhibiting a logarithmic type relationship with the percent improvement. The thickness of the 1-lift overlays did not appear to be a critical factor after the pre-overlay IRI values were taken into account, however 2-lift overlays with an intermediate asphalt lift less than one inch thick did not show the same rideability improvement as a layer that was approximately 2 inches thick.

Supplemental Notes:

This paper was sponsored by TRB committee AFD90 Surface Properties - Vehicle Interaction. Alternate title: Factors Affecting International Roughness Index of Asphalt Overlays.

Monograph Accession #:

01503729

Report/Paper Numbers:

14-1743

Language:

English

Corporate Authors:

Transportation Research Board

500 Fifth Street, NW
Washington, DC 20001 United States

Authors:

Smith, Bryan

Pagination:

18p

Publication Date:

2014

Conference:

Transportation Research Board 93rd Annual Meeting

Location: Washington DC
Date: 2014-1-12 to 2014-1-16
Sponsors: Transportation Research Board

Media Type:

Digital/other

Features:

Figures; References; Tables

Identifier Terms:

International Roughness Index

Uncontrolled Terms:

Pay adjustment

Geographic Terms:

South Carolina

Subject Areas:

Highways; Pavements; I22: Design of Pavements, Railways and Guideways

Source Data:

Transportation Research Board Annual Meeting 2014 Paper #14-1743

Files:

TRIS, TRB, ATRI

Created Date:

Jan 27 2014 2:38PM