Asphalt binder modified with recycled tyre rubber

Abstract

In the last few decades, tyre rubber waste has been considered a risky issue to the ecosystem. A huge amount of used and deformed tyres is disposed of in landfill or recycled into other products. The main goal is to modify 60/70 bitumen grade to achieve 40/50 bitumen results. In this work, tyre rubber waste was added at different weights from 5 to 20% after cutting into small particles to use in the modification process of 60/70 asphalt binder. The modified asphalt was tested to meet the Iraqi standard specifications of roads and bridges. In the experimental work, Central Composite Design was applied to attain mathematical models that describes binder consistency by relating three operating parameters: tyre rubber ratio, mixing temperature and time. The predicted models relate to the penetration and softening point of the modified binder achieved R 2 of 97 and 99%, respectively. The obtained results indicated that the penetration and softening point improved after adding 20% recycled tyre rubber at 170°C and 20 min of mixing time.

Keywords

• tyre waste
• crumb rubber
• modified bitumen
• design of experiments