Determination of asphalt mixture creep compliance at low temperatures by using thin beam specimens

Adam Zofka, Mihai O. Marasteanu, Mugurel Turos

Research output: Contribution to journalArticlepeer-review

31 Scopus citations


The thermal cracking (TC) module (TCMODEL) of the recently developed Guide for Mechanistic-Empirical Design of New and Rehabilitated Pavement Structures (referred to as MEPDG) is used to predict thermally induced cracking in asphalt pavements over their service lives. The primary input to this model is the asphalt mixture creep compliance. The current standard test for determination of the creep compliance of asphalt mixtures is the indirect tensile test (IDT). This paper investigates the feasibility of using the bending beam rheometer (BBR) device to determine the low-temperature creep compliance of thin asphalt mixture beams (127 times; 12.7 times; 6.35 mm). The BBR device was used to evaluate 20 different asphalt mixtures, and the results were compared with the standard IDT results. Direct comparison of the BBR and the IDT results indicated that both methods produce slightly different creep compliance curves and that the relative ratio between the BBR and the IDT results varies with time and temperature. A simple phenomenological relation that gives good predictions of the IDT results on the basis of BBR creep compliance is proposed. The measured and predicted creep compliance curves were input into the MEPDG TC module, and the predicted depth of cracks and the amount of cracking were compared. The comparison showed that predicted creep compliance determined on the basis of the BBR results can be successfully used to estimate thermal cracking by use of the TCMODEL. It was concluded that the BBR device can be used for the practical and surrogate estimation of the creep compliance of mixtures. The proposed equation relating BBR and IDT creep compliances should be further validated with different types of mixtures.

Original languageEnglish (US)
Pages (from-to)134-139
Number of pages6
JournalTransportation Research Record
Issue number2057
StatePublished - Dec 1 2008

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