Recycling old tires into asphalt, also known as rubberized asphalt, is a sustainable method of reducing tire waste and creating durable road surfaces. This process involves incorporating crumb rubber, derived from shredded tires, into asphalt mixes. Below is an outline of the tools, requirements, and steps needed to complete this process.
Tools and Equipment Required
1. Tire Shredding Equipment:
• Primary Shredder: Breaks down whole tires into manageable pieces.
• Secondary Granulator: Further processes the shredded rubber into finer crumb rubber.
• Magnetic Separator: Removes metal components such as steel belts from shredded tires.
2. Asphalt Mixing Equipment:
• Hot Mix Asphalt Plant: Combines crumb rubber with traditional asphalt and aggregates at high temperatures.
• Modified Asphalt Storage Tanks: Stores rubberized asphalt for transport or on-site use.
• Batch Mixers: Ensures even distribution of crumb rubber within the asphalt.
3. Quality Control Tools:
• Particle Size Analyzer: Ensures crumb rubber is of the required size for mixing.
• Temperature Gauges: Monitors mix temperatures during production.
• Testing Apparatus: Tests the final mix for durability and flexibility.
4. Safety Gear:
• Protective gloves, goggles, and heat-resistant clothing for workers handling hot materials.
Requirements
1. Materials:
• Discarded Tires: Source old tires from tire recycling centers, auto shops, or waste collection points.
• Aggregate: Crushed stones, gravel, or sand used as a base material in asphalt.
• Bitumen: The binding agent used in asphalt production.
2. Regulations:
• Ensure compliance with local environmental and safety regulations for recycling and road construction.
• Obtain permits for operating shredding and mixing equipment if required.
3. Facility Setup:
• A processing plant with space for tire shredding, crumb rubber storage, and asphalt production.
• Adequate ventilation to manage heat and emissions.
4. Workforce:
• Skilled operators for shredding, mixing, and quality control processes.
Process of Recycling Tires Into Asphalt
1. Tire Collection and Preparation:
• Gather discarded tires and inspect them for contaminants (e.g., mud, oil, or chemicals).
• Remove non-rubber components such as steel belts and fiber reinforcements.
2. Shredding and Crumb Rubber Production:
• Use shredders to cut the tires into smaller pieces.
• Process the shredded rubber through granulators to create crumb rubber of the desired particle size.
• Employ magnetic separators to extract any remaining metal.
3. Crumb Rubber Integration:
• Heat the bitumen in the hot mix asphalt plant to a temperature of 300–350°F (149–177°C).
• Add crumb rubber to the heated bitumen at a ratio typically between 10–20% by weight.
• Allow the mixture to react for a specified duration (usually 45–60 minutes) to ensure proper blending and swelling of the rubber particles.
4. Asphalt Mixing:
• Combine the rubberized bitumen with aggregates in the asphalt mixer.
• Ensure even distribution of crumb rubber for a consistent final product.
5. Testing and Quality Assurance:
• Conduct laboratory tests to check for performance indicators like elasticity, durability, and resistance to temperature variations.
• Adjust the mix design if necessary.
6. Transportation and Application:
• Transport the rubberized asphalt to the construction site using insulated trucks.
• Apply it using standard paving equipment, ensuring the surface is evenly spread and compacted.
Advantages of Rubberized Asphalt
• Durability: Increased flexibility and resistance to cracking.
• Noise Reduction: Rubberized asphalt reduces road noise compared to traditional asphalt.
• Eco-Friendly: Reuses tire waste and reduces reliance on non-renewable resources.
Recycling old tires into asphalt is a practical and environmentally responsible approach to managing tire waste while enhancing road infrastructure. With the right tools, facilities, and expertise, this process can be a valuable addition to sustainable construction practices.