Diverting Inert Waste to Beneficial Use in Asphalt Pavement

1. Picture Source: Franklin District Council Background Pressure from Legislation (Landfill Tax, Aggregates Levy etc.) Depletion of Quality Materials Incentive for Environmental Labelling and Marketing Prudent Use of Natural Resources and Effective Management of Waste • Candidate Material • Glass • Scrap Tyre • Steel Slag • Plastics UK Produces 25-30Mt of Hot Mix Asphalt Per Annum Use of Recycled Materials in Asphalt Pavement Dual Sustainability Benefits Reduce Volume for Landfill Disposal Reduce Demand for Mineral Extraction Picture Source: EUROSLAG • Barriers/Concerns: • Inferior Engineering Properties • Adverse Environmental Impacts • Additional Costs Picture Source: Ecorecycle Victoria • Target Use in Pavement • Asphalt Surface and Binder Course • Why? • More maintenance and repair work • Increase of traffic and axle-load calls for quality riding • Surface material represents a value application • As a Result: • Additional and higher property requirement • More processing activities • Objectives • Study origin of, and market for, recycled materials • Investigate engineering properties and limits • Quantify benefits and/or risks to the environment • Calculate associated savings/costs • Find reasonable balance between the above aspects. Picture Source: British Glass • Engineering Properties and Limits • Requirement for 1) Aggregates: BS EN13043 • Geometric (BS EN933) • Physical and Mechanical (BS EN1097) • Chemical (BS EN1744) • Thermal and Weathering (BS EN1367) • 2) Asphalt: BS594, BS4987 • 3) Surface Course: BS EN13036 • Skid resistance • Tyre noise reduction • Ability to drain off surface water quickly • Factors to Consider prior to Use: • Asphalt mixture type (e.g. SMA, HRA) • Particle size of recycled constituent and replacement rate • Recycling (e.g. cold in-situ) and processing technique • Recyclability of pavement containing secondary aggregates • Economics • Recycling efforts must be supported by a robust market and value-added end use. • Disincentives: • Lack of collecting infrastructure • High processing cost and insufficient redemption (e.g. PRNs) • Competition from alternative use of recycled materials • Limited market information due to commercial restriction • Solution: • Investment to facilitate and encourage returning and recycling waste • Find the right source for asphalt use in both technical and financial terms • Government efforts (e.g. WRAP, TRL) to provide open and unbiased information • Environmental Savings and Risks • Life cycle assessment (LCA) is to be used. • Loadings Assessed as being Significant: • Resources depletion: mineral, energy, etc. • Atmospheric emission: CO2, NOx, SO2, VOC, CO, PM, etc. • Leaching into soil and ground water: trace metals, chloride, etc. • Others: noise, dust, odour, etc. • Resources: • International standard (BS EN ISO14040 series, etc.) • Relevant models and databases (PaLATE, BEES, SimaPro, etc.) Diverting Inert Waste to Beneficial Use in Asphalt Pavement Picture Source: AAPT For further information please contact: Yue Huang, PhD Student Yue.Huang@ncl.ac.uk