Laboratory Evaluation of Modified Asphalt Mixture Properties and Aggregate Grading by Superpave System | ||
| Journal of University of Babylon | ||
| Article 1, Volume 22, Issue 4, June 2014, Pages 724-731 | ||
| Authors | ||
| Mohammed Aziz Hameed Al-Shaybani; Nahla Yassoub Ahmed | ||
| Abstract | ||
| In Iraq, the using of conventional asphalt cement in mix design causes unnecessary road maintenance. It is necessary to use additive materials in pavement construction as modifiers which could improve the performance of asphalt concrete pavements mixture. The major objective of this research is to evaluate the effects of polymer modification and aggregate gradation for Superpave system on the properties of hot mix asphalt by using asphalt from Al- Daurah refinery with two locally polymers. These polymers are represented by high density polyethylene (HDPE) and styrene butadiene styrene (SBS) with using three aggregate gradations [(Above Restricted Zone) (A), Through Restricted Zone (T), and Under Restricted Zone (U)]. The performance of polymer asphalt mixtures are evaluated using indirect tensile test and wheel track test. The results confirm that the indirect tensile strength and resistance to rutting of polymer asphalt mixtures are largely dependent on polymer type, polymer concentration and aggregate gradation. It is concluded that the addition of polymer to asphalt mixtures shown the permanent deformation are decreased by (189%) at 40°C and by (271%) at 50°C and indirect tensile strength is increased by (42%), after compared with control mixtures. The addition of SBS and HDPE with 3% for each one to asphalt mixtures showed better properties of pavement. Also the gradation above restricted zone give a good tensile strength and high resistance to rutting from other gradations. Increasing the test temperature from (40 to 50)°C, the permanent deformation (rutting depth) also increased by (100%). | ||
| Keywords | ||
| asphalt; pavement; superpave; polymer; aggregate; gradation; performance | ||
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