Slag is used all over the world in road and railway construction and for engineering, and has many advantages over natural rock.
Slags are one of the most natural products of all. Slags are principally divided into blast furnace slag and metallurgical slag. At voestalpine the slags resulting from the steelmaking process are separated into blast furnace and metallurgical slags and then recycled. The separated slags are processed into valuable products.
Due to its positive technical characteristics, LD slag is used all over the world in road and railway construction and for engineering. The most common use is as an aggregate in the manufacture of asphalt. It is also successfully used as an aggregate for concrete.
Slag use is subject to strict regulations and standards.
The use of slag is clearly regulated for particular applications. For instance, production of aggregates is carried out in accordance with the European Construction Product Directive and harmonized, European standards:
- EN 12620/aggregates for concrete
- EN 13043/aggregates for asphalt and surface treatments for road, airports, and other traffic zones as well as
- EN 13242/aggregates for unbound and hydraulically bound mixtures for use in engineering and road construction.
Advantages of LD slag in road construction
LD slag has a series of advantages over natural rock in the field of road construction.
Slag has a greater PSV (Polished Stone Value): i.e., greater resistance to wear. This is the result of its mineral composition. The consequences: less wear and longer road lifetimes. Roads constructed using LD slag demonstrate reduced rutting.
LD slag has micropores and therefore, it retains its adhesiveness with wear. In contrast, natural rock becomes smooth with wear—its surface becomes polished and slippery.
As a result, tires can grip better on surfaces constructed using LD slag, and this is particularly important on highways and in curves.
Greater stability and reduced wear
LD slag is harder and internally bound. Natural gravel does not have the same stability and load bearing capacity. As LD slag is harder and more compact than natural rock, roads last longer. And as there is less wear, particulate pollution is reduced.
A disadvantage of LD slag is its greater weight compared to natural rock, and this has an impact on logistics and transport costs.
Further facts and figures on LD slag: http://bit.ly/ld-slag