Alternatively the molten slag can be quenched rapidly by passing it through a trough of high pressure, high volume water sprays the heat energy contained in the molten slag causes it to explode and instantly form Granulated Blast Furnace Slag or GBFS.

On a casual examination, GBFS would pass for river sand with a top size of about 6mm. It has a density of about 60% to 70% of natural sand.

GBFS may be used without further processing as a construction sand, soil/pavement stabilising media or grit blasting material. 

GBFS has been evaluated by NSW Government Work Cover and laboratory results show the absence of free silica which makes the use of natural sand potentially hazardous to workers’ health.

Typical uses for GBFS are:

• As a general-purpose construction sand in civil engineering applications
• As an ideal select fill behind reinforced earth wall construction. Within a relatively short time, the pozzolanic properties of granulate cause it to set up and form a solid block
• In glass manufacture as a source of alumina and silica.
• As a stabilizing agent in road construction. There have also been examples where only granulate has been used a pavement material.
• Pavements now exist where granulate has been used in conjunction with steel slag to form very heavy-duty pavements.
• As a grit blasting media: Granulate is particularly suitable on soft metals such as aluminum where a light etch is required.

When finely ground to form Ground Granulated Blast Furnace Slag or GGBFS, its applications widen to include uses in activation of granular pavement materials and as a cementitious material in the manufacture of concrete, particularly where resistance to aggressive ground, water and aggressive environmental conditions are present.

Typical uses for ground granulated slag are:

• Activator for stabilizing granular pavement materials as the only stabilizing agent or in conjunction with small quantities of lime.
• As a general cementitious replacement (25 – 50%) for Ordinary Portland Cement in concrete construction.
• As a significant cementitious replacement (min 65%) for Ordinary Portland Cement where long term durability in aggressive ground, water or air environments is required.
• As a high cementitious replacement (>80%) in special grout mixes