You can safely use a basic grade of biochar which may contain some contaminants, which are not going to leach out of the asphalt, This will help you to keep the cost to a minimum.:
• Urban: Might be used in tree planting, park maintenance, rainwater drainage, filtration, ...
• Consumer Material: Might be used products that may come into direct skin contact with consumers or food-grade products
• Basic Material: Might be used in basic industry such as to produce building materials, road construction asphalt, ...

Approximate cost per tonne: The approximate cost per tonne of the selected biochar type in €.

Biochar Density: The biochar density in tonne per cubic metre.

Roadway Length: How many metres of roadway do you want to replace? Asphalt is usually laid in three separate courses, a base course, a binding course and a wearing course. To give an example: a typical bi-directional roadway in a town is 6.4m wide. It will require a base course that is 200mm thick, a binder course that is 60 mm thick and a wearing course that is 40 mm thick giving a total depth of 300 mm

To give an example: a typical bi-directional roadway in a town is 6.4m wide..

Roadway Thickness: To give an example: a typical bi-directional roadway in a town requires a base course that is 200mm thick, a binder course that is 60 mm thick and a wearing course that is 40 mm thick giving a total depth of 300 mm

Application rate: The recommended application rate is between 3.0 - 8.0 % by volume depending on the level of traffic on the road surface

Cycleway Length: How many metres of cycleway do you want to replace? A typical cyclepath is 4.8m wide. It has a base course of 125 mm, a binder course of 50 mm and a wearing course of 25 mm, giving a total depth of 200 mm.

To give an example: A typical cyclepath is 4.8m wide.

Cycleway Thickness: To give an example: a typical cycleway has a base course of 125 mm, a binder course of 50 mm and a wearing course of 25 mm, giving a total depth of 200 mm.

Application rate: The recommended application rate is between 3.0 - 8.0 % by volume depending on the level of traffic on the cycleway surface

Emissions multiplier or baseline displacement factor for life-cycle carbon calculations.