Dry Process Crumb Rubber Modification in Warm Mix Asphalt

---

Tezin Türü: Yüksek Lisans

Tezin Yürütüldüğü Kurum: Orta Doğu Teknik Üniversitesi, Fen Bilimleri Enstitüsü, Fen Bilimleri Enstitüsü, Türkiye

Tezin Onay Tarihi: 2018

Öğrenci: Farshad Kamran

Asıl Danışman (Eş Danışmanlı Tezler İçin): HANDE IŞIK ÖZTÜRK

Özet:

Since the last decade, environmentally friendly asphalt production techniques have significantly advanced for savings in natural resources, energy and economy. From these techniques, Warm Mix Asphalt (WMA) provides a reduction in mixing and compaction temperatures and also overcomes various challenges of Hot Mix Asphalt (HMA). Additionally, Crumb rubber (CR) modification of asphalt mixtures helps the disposal of waste tires and also improves the asphalt mixtures properties. Among CR modification methods, dry process (Dry) method has various advantages. Thus, the focus of the study is to overcome the major disadvantages of Dry CR (i.e. high production temperatures) with WMA additive. In this study, the association of WMA and dry process are studied for the first time through a broad laboratory study. Therefore, seven different asphalt mixtures including HMA, dry process CR modified HMA (DryHMA) and five sets of dry process CR modified WMA (DryWMA) are prepared to analyze the compactibility, volumetrics, and low-temperature performance properties of these mixtures. DryWMA mixes are prepared by changing various design parameters (i.e. WMA additive dosage, conditioning time, compaction and mixing temperatures). The results of this study stated that the decrease in the mixing temperatures could not be compensated by extending the conditioning time. However, the compaction temperature could be considerably lowered without compromising the low-temperature performance and strength of the mixes. In addition, use of the WMA additive with the dry CR modified mixtures provides better compactibility and workability. Moreover, the decreases in the cooling rate of DryWMA provides longer compaction frame.