Evaluation of I-FIT Results and Machine Variability using MnRoad Test Track Mixtures

Ozer, Hasan; Al-Qadi, Imad L.; Barber, Edoardo; Okte, Egemen; Zhu, Zehui; Wu, Shenghua

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https://hdl.handle.net/2142/96284 Copy

Description

Title

Evaluation of I-FIT Results and Machine Variability using MnRoad Test Track Mixtures

Author(s)

• Ozer, Hasan
• Al-Qadi, Imad L.
• Barber, Edoardo
• Okte, Egemen
• Zhu, Zehui
• Wu, Shenghua

Issue Date

2017-06

Keyword(s)

Asphalt mixture, fracture, machine, Illinois Flexibility Index (I-FIT)

Abstract

The Illinois Flexibility Index Test (I-FIT) was developed to distinguish between different mixtures in terms of potential cracking. Several machines were manufactured and are currently available to perform the I-FIT. This report presents the results and findings from an experimental program developed to compare various I-FIT configurations. Three different I-FIT devices were compared in collaboration with Illinois Department of Transportation (IDOT). The main focus of the study was the comparison of the two custom designs: an InstroTek screwdriven device with a spring rollers support system and a TestQuip servo hydraulic system with both spring and bearing rollers support systems. In addition, the Interlaken 100 kN servo-hydraulic universal testing frame equipped with an I-FIT fixture with spring roller support system was also evaluated. In total, eight asphalt concrete (AC) mixtures with varying design characteristics were analyzed by evaluating the difference in the mean values of fracture energy, slope, and overall patterns of load-displacement curves in addition to the statistical analysis. According to the results obtained, the various machines did not significantly affect the flexibility index (FI) calculated for each mixture in this study. In all cases, the results were within approximately one unit of FI for each machine and mixture. Statistical analysis conducted using the ANOVA analysis and t-test also supported the conclusion that the device configurations were found to have no significant effect on the FI results for the AC mixtures evaluated in this study, regardless of the loading system (hydraulic or screw-driven) and the configuration of the support system (spring or bearing rollers).

Publisher

Illinois Center for Transportation/Illinois Department of Transportation

Series/Report Name or Number

FHWA-ICT-17-012

Type of Resource

text

Language

en

Permalink

http://hdl.handle.net/2142/96284

DOI

ISSN 0197-9191

Sponsor(s)/Grant Number(s)

IDOT-R27-SP31

Copyright and License Information

No restrictions. This document is available through the National Technical Information Service, Springfield, VA 22161.

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