Rheological characteristics of EVA modified bitumen and their correlations with bitumen concrete properties Claudio Brovelli a , Loic Hilliou b,⇑ , Yacine Hemar c , Jorge Pais d , Paulo Pereira d , Maurizio Crispino a a School of Civil and Environmental Engineering, Politecnico di Milano, Piazza Leonardo da Vinci 32, 20133 Milan, Italy b Institute for Polymers and Composites/I3N, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal c School of Chemical Sciences, The University of Auckland, Private Bag 92019, Auckland, New Zealand d Department of Civil Engineering, University of Minho, Campus de Azurém, 4800-058 Guimarães, Portugal highlights  The rheological modification by EVA depends on the bitumen grade.  The rheology of modified bitumens is not rationalized by emulsion models.  A simplified method is introduced to rationalize the data by the Palierne model.  Palierne model only describes the rheology for a limited range of frequencies.  Power laws relate modified bitumens and bitumen mixtures viscoelastic properties. article info Article history: Received 1 May 2013 Received in revised form 17 July 2013 Accepted 21 July 2013 Available online 28 August 2013 Keywords: Bitumen Rheology Polymer Rut depth Palierne model abstract Polymer modified bitumens (PMBs) were prepared by mixing bitumen from two different sources with an EVA copolymer. The rheological characteristics of the PMBs were analyzed using small amplitude oscillatory shear and steady shear tests. Data were analyzed with rheological models developed for par- ticle suspensions and with Palierne’s model for polymer blends. Results indicate that such models cannot account for the EVA modification of the bitumen in the whole range of temperatures, frequencies and shear rates studied. The effects of EVA on the PMBs viscoelastic properties and morphology depend on the type of bitumen considered. However, power law relationships between the rheological functions of PMBs and the Young complex modulus and the rut depth of corresponding mastics are identified. Ó 2013 Elsevier Ltd. All rights reserved. 1. Introduction The performance of road pavements is mainly due to the visco- elastic properties of bitumen, and varies with the source of the crude petroleum and the method of manufacturing [1–3]. Bitumen viscoelastic behavior is usually characterized with small amplitude oscillatory shear (SAOS) experiments through the determination of rheological functions such as the storage modulus G 0 , the loss mod- ulus G 00 and tan d [4,5]. New rheologically determined indices have been recently proposed to quantify bitumen aging [6,7] and the sta- bility of polymer modified bitumens (PMBs) upon storage [8]. The addition of polymers or recycled polymers to bitumen is a common route to improve their rheological properties and consequently produce better pavements [9]. Bitumen modification is generally carried out during the refining processes of petroleum, by adding the polymer into the refined-bitumen. Another way for producing PMBs is adding polymers in laboratories under controlled conditions using batch mixers with specifically designed spindles (as in the case of modified bitumen emulsions). The quality of PMBs mainly depends on the stability of the components and the affinity between bitumen and polymer. Hence, PMBs are generally sold as ready-to-use finished products, and are inherently expensive. Thus, the addition of polymers directly into ordinary bitumen at the asphalt plant would be more economical and useful. From a rheological view point, bitumen is a complex fluid which can exhibit different behaviors, such as solid-like, viscoelastic or Newtonian behaviors [10], depending on the range of temperatures and pressures. In addition, it is generally agreed that bitumen is bet- ter described as a multidisperse colloidal system due to the com- plexity of its micro-scale and molecular compounds, and its varied composition [1,9]. The first SAOS studies of bitumen showed that it is a thermorheologically simple material [1,4], meaning that the linear viscoelastic response of the bitumen at any given time can 0950-0618/$ - see front matter Ó 2013 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.conbuildmat.2013.07.032 ⇑ Corresponding author. Tel.: +351 253510320; fax: +351 253510339. E-mail address: loic@dep.uminho.pt (L. Hilliou). Construction and Building Materials 48 (2013) 1202–1208 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat