GGBFS (Ground Granulated Blast-Furnace Slag) Powder

We are leading manufacturer of Ground Granulated Blast-Furnace Slag Powder

GGBS or Ground Granulated Blast-furnace Slag is a cementitious material that is used mainly in concrete and is a byproduct of blast furnaces used to make iron.

 

Manufacturing Process:

GGBS or granulated blast furnace slag is obtained by heating iron ore, limestone and coke to a temperature of approximately 1500 degrees Celsius in a blast furnace. The by-product of the manufacture of iron is a molten slag and cast iron. The molten slag consists of alumina and silica, also with a certain amount of oxides.

After the molten slag has been rapidly extinguished by passing it through a trough of high pressure, high volume water sprays. The cooling optimizes the cementitious properties and produces granules similar to a coarse sand. This granulated slag is dried and ground to a fine powder.

The main constituents of blast furnace slag are CaO, SiO2, Al2O3, and MgO which are found in most of the cementitious substances.

 

Composition difference of GGBFS and Portland cement:

Constituents          GGBFS                 Portland Cement
CaO                               30-50%              57-66%
SiO2                              28-40%              19-24%
Al2O3                          8-24%                 2-8%
MgO                              1-18%                   0-5%

 

Uses of GGBS:

The main use of GGBS is in ready-mix concrete. GGBS is usually supplied as a separate material and combined with Portland cement. However, it can also be mixed with Portland cement clinker in a cement factory and marketed as “Portland slag” or “blast furnace” cement.

When adding GGBS at the concrete mixer:

  • Increases the strength and durability of the concrete structure
  • Reduces transport burdens, because the addition can be delivered directly to the concrete plant without having to go via a cement factory
  • Increases flexibility to vary the proportion and thereby optimise the technical performance of the concrete
  • It reduces voids in concrete hence reducing permeability
  • Increased sulfate resistance
  • Increased alkali silica reaction resistance
  • The maintenance and repair cost of structures are reduced thus increasing the life cycle of concrete structures
  • Unlike cement, GGBFS does not produce carbon dioxide, sulphur dioxide or nitrogen oxides

 

GGBFS particles have a very glassy texture that increases their workability. This can help reduce water and superplasticizers to achieve proper workability in common situations.

GGBFS as a replacement has lower water demand due to its glassy texture. The glassy surface of the GGBFS particles does not absorb water on its surface.

GGBFS faces certain obstacles in its implementation widely due to the low force gain rate. It is also very sensitive to the curing conditions. Therefore, a better quality curing process ensures full utilization of GGBFS.

 

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