Materials Sciences and Applications, 2013, 4, 312-318 http://dx.doi.org/10.4236/msa.2013.45040 Published Online May 2013 (http://www.scirp.org/journal/msa) Analysis of the Rheological Behavior of Aging Bitumen and Predicting the Risk of Permanent Deformation of Asphalt Samia Saoula 1* , Khedoudja Soudani 1 , Smail Haddadi 1 , Maria Eugenia Munoz 2 , Antxon Santamaria 2 1 Laboratory of Environment, Water Geomechanics and Structures, Faculty of Civil Engineering, University of Sciences and Tech- nology Houari Boumediene, Algiers, Algeria; 2 Department of Science and Technology of Polymers, Faculty of Chemistry, Univer- sity of the Basque Country, San Sebastian, Spain. Email: * ssaoula1@yahoo.fr Received February 27 th , 2013; revised April 2 nd , 2013; accepted April 14 th , 2013 Copyright © 2013 Samia Saoula et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. ABSTRACT The aging of bitumen has a significant impact on the mechanical behavior of asphalt. This aging is carried out at the mixing operation with the aggregates generally at 163˚C in the case of pure mixtures or at temperatures higher than in the case of the modification by polymers or industrial waste. This paper presents experimental results of a study of the rheological behavior of a class of bitumen 40/50 to the artificial aging. Three aging temperatures were selected: 163˚C, 173˚C and 183˚C. From obtained results, a study of the risk of deformation of asphalt is performed, based on the results of correlation between the behavior of the coated and his binder deducted SHRP specifications and technical advice French. These results show that the stiffness of the aged binders increases with aging temperature. Moreover, there is no risk of rutting and fatigue cracking for thermal coated projected. Keywords: Aging; Bitumen; Rheology; Deformation; Rutting 1. Introduction Bituminous binders are widely used for road paving ap- plications [1]. The ageing of the bitumen during storage, mixing, transport and laying on the road, as well as in ser- vice life, are the most important problems presented by the use of bitumen in pavements [2]. Indeed, Bitumen ageing is a very complex process re- sulting in hardening of bitumens and embrittlement, both in application and in service, which contributes greatly to the deterioration of paving applications [3]. Important ageing related modes of failure are traffic and thermally induced cracking, and ravelling and shor- ten the lifespan of pavement [4,5]. In bitumen aging, two types of mechanisms are invo- lved. The main aging mechanism is an irreversible one, characterised by chemical changes of the binder, which in turn has an impact on the rheological properties [6]. The second mechanism is a reversible process called phy- sical hardening [7,8]. Physical hardening may be attrib- uted to molecular structuring [5]. Several methods have been proposed to replicate the effect of aging and, therefore, to foresee bitumen behav- ior during application and service life. To simulate the age hardening occurring during plant mixing and lay- down the most utilised test is Rolling Thin Film Oven Test (RTFOT, ASTM D-2872). The age hardening is evaluated by observing how viscosity, penetration and softening point change with aging [3]. Aging, which oc- curs in asphalt roadway pavements during construction and service life, affect the rheological properties of bitu- men [5,8]. Rheology involves the study and evaluation of the time—temperature dependent response of materials that are stressed or subjected to an applied force. Rheological properties of bitumen consist of age hardening, tempera- ture susceptibility, shear susceptibility, stiffness, penetra- tion, ductility, and viscosity [9]. Over the past few years, rheology has been extensively used in order to classify and evaluate bituminous binders according to their performance properties. This has led to a better knowledge of bitumen behaviour that occurs when subjected to different thermal and mechanical conditions, as seen during road construction and service in the field [3]. One of the key material properties of bitumen is the complex modulus. This property is related to major dis- * Corresponding author. Copyright © 2013 SciRes. MSA