Evaluating the mechanical properties of terminal blend tire rubber mixtures incorporating RAP Munir D. Nazzal a,⇑ , Md. Tanvir Iqbal b , Sang Soo Kim a , Ala Abbas c , Md. Tanvir Quasema b , Walaa Mogawer d a Civil Engineering Department, Ohio University, Athens, OH 45701, United States b Civil Engineering Department, Ohio University, Athens, OH, United States c Civil Engineering Department, University of Akron, Akron, OH 45701, United States d Civil Engineering Department, University of Massachusetts, Fall River, MA, United States highlights  The GTR mixing speed is an important factors that affects the low-temperature properties of the GTR modified binder.  GTR mixtures had similar cracking and rutting resistance to the PG 76-22 polymer modified mixes.  There was no significant difference in the performance of the considered cryogenic and ambient GTR modified binders and mixes. article info Article history: Received 12 August 2016 Received in revised form 23 December 2016 Accepted 25 January 2017 Keywords: Terminal blend GTR RAP Low temperature cracking abstract This paper documents the results of a laboratory testing program that was conducted to evaluate the mechanical properties of mixtures incorporating terminal blend ground tire rubber (GTR) modified asphalt binders and reclaimed asphalt pavement (RAP) and compare them to those produced using poly- mer modified binders. The laboratory testing program included ambient and cryogenic GTR modified asphalt binders as well as two polymer modified asphalt binders meeting specifications for performance grade (PG) 70-22M and PG 76-22M. The laboratory tests results indicated that the GTR mixing speed affects the low-temperature properties of the GTR modified binders. Furthermore, mixtures prepared with GTR modified binders had better tensile properties as well as resistance to low-temperature crack- ing and rutting than those prepared using the polymer modified PG 70-22M but similar to those with PG 76-22M polymer modified binder. In addition, the GTR modified mixes had comparable resistance to moisture-induced damage to those prepared using the considered polymer modified binders. In general, there was no significant difference in the performance of the considered cryogenic and ambient GTR modified binders and mixes. Ó 2017 Elsevier Ltd. All rights reserved. 1. Introduction The increase in the carbon dioxide (CO 2 ) and other greenhouse emissions has contributed to the thinning of the ozone layer, which is thought to be responsible for the global warming and the increased occurrence of natural disasters [8]. Thus, there has been a growing interest to reduce the CO 2 emissions. One way that can be used to achieve that is to increase the use of recycled materials such as reclaimed asphalt pavement (RAP) ground tire rubber (GTR) [4]. GTR has been incorporated in asphalt binders and mix- tures using two method groups, namely the dry method and the wet method [5]. In the dry method, GTR is added to the aggregates before mixing with the binder, while in the wet methods, GTR is blended with the asphalt binder before producing the mix. The lat- ter is expected to provide better blending between the GTR parti- cles and the asphalt binder, resulting in better GTR mixes performance [5]. GTR modified asphalt binders has been produced using the wet method by adding coarse GTR to the asphalt binder and agitating them in a special unit at high temperatures to stimulate the phys- ical and chemical bonding between the two materials. More recently GTR modified binders were produced by adding finer GTR particles to the asphalt liquid material at the binder storage or distribution terminal before transporting it to the asphalt plant. The GTR modified binder produced using this method is commonly referred to as terminal blend GTR or pre-blended GTR. Terminal blend GTR method eliminates the need for the specialized blending http://dx.doi.org/10.1016/j.conbuildmat.2017.01.102 0950-0618/Ó 2017 Elsevier Ltd. All rights reserved. ⇑ Corresponding author. E-mail address: nazzal@ohio.edu (M.D. Nazzal). Construction and Building Materials 138 (2017) 427–433 Contents lists available at ScienceDirect Construction and Building Materials journal homepage: www.elsevier.com/locate/conbuildmat