Q. What do you mean by GGBS – cement replacement?

From structural point of view GGBS replacement enhances higher durability, lower heat of hydration and higher resistance to sulphate and chloride attack when compared with normal ordinary concrete. Conversely it also contributes to environmental protection since it minimizes use of cement throughout the production of concrete. 

Though it is identified that there are still some hindrances which prevent the prevalence of its usage in local market. Theoretically speaking GGBS concrete suffers from lower rate of strength development that is highly sensitive to curing conditions. In this connection certain site measures have to be introduced to construction industry to ensure better quality of curing process in order to secure high quality of GGBS concrete. Along with designers have to be cautious of the potential bleeding problem of GGBS concrete.

Another main difficulty of extensive use of GGBS concrete lies in the little source of supply of GGBS. As Hong Kong isn't a major producer of steel and GGBS as a by-product of steel has to be imported overseas and this introduces higher material cost because of transportation and supply of GGBS is unsteady andunstable.