Effects on investment
Asphalt Recycling
The current technical production facilities have experience with 70% recycling of base- and bind layers of asphalt and 0-30% in surface layers. The limitation in the surface layers is mainly due to the experienced risk of losing too much skid resistance during the lifetime period. Safety for road users is obvious.
Base and bind layers with 70% recycled material can be used without restriction. A restriction is imposed on higher levels, produced using the direct heating method, because burning bituminous materials leads to an increase in antimony content. Antimony is a metalloid that remains on the stone when bitumen is burned. Leaching antimony can pollute water due to its toxicity. With indirect heating (hot gas generator), 80% to 100% recycled material can be used, as the temperature of the parallel drum can be tempered so that the bitumen does not burn.
In the future, asphalt mixes will be more and more functionally specified, and empirical design prescription will be replaced. Prescriptions currently being imposed on maximum amounts of recycling will be exposed by the need for circular thinking, and replaced by functional limitations. If proven, they can effect a CO2 reduction in road building.
Currently, the highest amount of RAP is used in the Netherlands. This is because all raw materials have to be imported from abroad. It shows a simple economic value, because transport costs are lower. The use of 10% more RAP results in a reduction of production costs of approximately € 2,15/mt asphalt.
The prices shown are based on normal mineral costs, and the sieve and transport costs of RAP. The base bitumen for base and bindlayers is Pengrade 40/60 with a penetration level of 50. The amount of Rheofalt HP-AM is calculated using the logarithmic penetration formula, holding the penetration of the asphalt mix design at 50.
Price level of bitumen: € 350/mt.
| Rap Amount | Fresh bitumen 40/60 | RheoFalt HP-AM | Lopgpen mix | Pricelevel |
|---|---|---|---|---|
| No RAP | 5.0% | 0.0% | 50 | € 49.59 |
| 30% RAP | 3.39% | 0.11% | 50 | € 41.84 |
| 50% RAP | 2.31% | 0.19% | 50 | € 37.67 |
| 70% RAP | 1.24% | 0.26% | 50 | € 33.20 |
| 100% RAP | 0.0% | 0.38% | 50 | € 30.50 |