How Old Tires Are Turned Into Asphalt
Every year, millions of old car tires end up in giant landfills, creating an environmental crisis. They take thousands of years to decompose, and attempts to burn or bury them pollute the soil, air, and oceans. In this documentary study of waste recycling, we'll explore how modern engineering and technology are transforming toxic tires into durable, long-lasting road surfaces. You'll see the complete transformation journey from hazardous waste to innovative rubber-bitumen asphalt.
The primary stage begins in factories, where worn tires are shredded into high-powered machines. Tires contain an armored carcass: steel cord, textile, and dense rubber. Conventional blades become dull on the rubber within hours, so engineers developed knives made of superhard alloys with a special tooth profile. The discs clamp onto the wheel and tear it apart along its internal bonds, shredding the tires without continuously overheating the equipment.
Next, the material passes through neodymium magnetic separators. A powerful magnetic field captures tons of steel wire, separating the metal from the rubber to prevent corrosion and the formation of voids within the future road surface. Cryogenic grinding is used to produce the finest rubber dust: the raw material is cooled with liquid nitrogen to minus 196 degrees Celsius. Frozen rubber loses its elasticity, becomes brittle as glass, and easily crumbles into powder under the blows of hammer mills.
The main technological challenge lies in the incompatibility of bitumen and rubber. Under normal conditions, the rubber floats and chars. To activate the material, special oils and modifiers are added to the mixture. In high-speed rotary mixers and colloid mills, synthesis occurs under high pressure at a temperature of 170 degrees Celsius: the rubber dust swells, absorbs bitumen, and forms a homogeneous elastic gel.
When laying rubber-bitumen asphalt, rollers press the hot mixture with crushed granite. The finished surface acts as a shock absorber: it resists ruts from trucks in the summer and resists frost cracks in the winter. Laboratory tests under hydraulic presses confirm that rubber-bitumen asphalt lasts three times longer than conventional asphalt and significantly reduces noise levels. Watch documentaries about technologies that are changing our planet and solving global environmental problems."