Q. Show the Differences Between GGBS and PFA?
The use of GGBS as substitute of cement improves smaller reliance on PFA. Particularly GGBS is supposed to be more compatible with renewable energy source objectives.
Replacement level of GGBS may be as high as 70% of cement. It is about twice as much of PFA (characteristically replacement level is 40%). Henceforth partial replacement of GGBS can allow higher reduction of cement content. As manufacture of one tonne of cement produces about 1 tonne of carbon dioxide and it is considered more ecologically friendly to adopt GGBS because of its potential higher level of cement replacement.
Performance of bleeding for PFA and GGBS varies. With PFA, bleeding is found to reducebecause of increased volume of fines. Though amount of bleeding of GGBS is found to upsurge when compared with OPC concrete in the long term. Conversely drying shrinkage is higher for GGBS concrete whereas it is lower for PFA concrete.
In terms of cost consideration, current market price of GGBS is similar to PFA. As the potential replacement of GGBS is much higher than PFA, substantial cost savings may be made by employing GGBS.