Outokumpu slag products (registered and sold under name OKTO) are environmentally safe.
Using OKTO products for road and infrastructure projects saves exhaustible natural materials like sand, gravel and crushed stone, and helps preserve groundwater reserves by reducing the need for new quarries. OKTO construction products include OKTO insulation material, OKTO aggregates and Croval aggregate.
OKTO insulation and filter material (granular size of 0/11 mm) is manufactured from melted ferrochrome slag through water cooling, i.e. granulation. Based on its particle size distribution, the product is sand. OKTO aggregates (0/5 mm, 4/8 mm, 4/11 mm, 8/11 mm, 10/16 mm and 16/22 mm) are manufactured from air cooled ferrochrome slag by crushing. The aggregate is firm and load-bearing. Due to its firmness, the best usage target for the OKTO aggregate is pavement that requires high durability. Good wear resistance is one important material technical property of the OKTO aggregate, and it makes the product a suitable raw material for pavements demanding excellent wear resistance.
Not only do OKTO products reduce the use of natural materials, but they also have superior technical qualities. For civil engineering purposes technical properties of ferrochrome slag products are better than in natural stones. For example, in granulated slag properties in road construction are:
- Apparent density of structure 1.65-1.8 Mg/m3
- Thermal conductivity 0.5 – 0.7 W/mK
- Hydraulic conductivity 10-3 – 10-4 m/s
- Capillarity 0.10 – 0.20 m