Optimization of Asphalt Mix Improved by the Addition of Scrap Tires
Falak O.Abass, Mohammed .O.Abass & Raghad.O.Abass

The design of improved asphalt mix is achieved by the use of three major variables , weight of scrap tires replaced by coarse base aggregate , particles size of scrap tires finally the weight of binder used (bitumen).
The improved asphalt mix (IAM) requires a balance between rut resistance and durability to resist cracking and moisture damage (stripping) .Accordingly several factors that influence rut resistance and durability are considered during the design process:
The mix consisted of binder (3.0-6.5) %wt. , scrap tires (10-30) wt% with particle size of (1-5) cm , is achieved by the application of box-Wilson design program.
The improved mix is achieved by the use of both hot (wet) and cold (dry) processes for preparing the standard mix firstly under high temperature 168˚C with a continuous mixing for 2 hours then mould this hot mixture in standard molder found with the replacement of a coarse percent of aggregate by the different sizes of scrap tires (1-5)cm by the use of cold ( dry) technique , finally a compression step is achieved with 52 hut for 20 min for both sides of molder in order to compress the prepared specimens then leaved for 24 hrs from the stability of specimens before any tests applied .
The results of selected variables are studied for prepared specimens to check different important properties (mechanical, physical, chemical, thermomechanical and thermo-physical properties), then applied these result properties data in analytical computer programme software to check its fitting to design model selected and calculated the optimum properties and optimum variables for improved asphalt mix.
After-ward the computerize analysis results shows that an optimum mix No.(11) reached high stability and flexibility, also gave excellent physical and chemical properties as shown in present work below. Also described in this work the application and comparison between standard and improved optimum asphalt mix.
Keywords: asphalt, scrap tires, preparation / properties / and application.