We are Leading manufacturer and supplier of GGBS. GGBS is added to concrete by addition at the concrete mixer, along with ordinary cement, aggregates and water. The normal ratios and proportions of aggregates and water to cementitous material in the mix remain unchanged. Mixing times are the same as for ordinary cement.
GGBS slag is by product of iron and steel manufacturing process. It contains the entire basic constituent of OPC but not exactly in the same ratio and chemical form.
Although these compounds are not identical to those found in Portland cement (i.e. tricalcium silicate, tricalcium aluminates etc), they hydrate when activated by calcium hydroxide generated during the hydration of Portland cement.
Since GGBS is almost 100% glassy, it is generally more reactive. This process of quenching is called granulation because it produces glassy granules similar in appearance to coarse sand, having excellent cementitious property when ground to high fineness and mixed with cement.
Slag itself has no cementing property but when mixed with OPC, it develops hydraulic properties similar to cement. The calcium oxide (CaO) found in slag is tied up as calcium silicate, calcium aluminates and calcium alumino silicates.