THE ROLE OF GROUND GRANULATED BLAST FURNACE SLAG IN THE SUSTAINABILITY OF CONCRETE STRUCTURES

The use as a partial cement replacement is well known and practiced. High volume replacement to cement. by Ground Granulated Blast Furnace Slag (GGBFS) in the order of 70-80% has been successfully done in major structures worldwide. Nevertheless, there is reluctance in the local industry to use GGBFS in quantities that exceed 35% as a cement replacing material. The benefits of high volume replacement however, go far beyond the economical advantage. There is now overwhelming evidence that GGBFS significantly enhances the durability of concrete structures. The benefit of enhanced durability is a major element in creating sustainable construction. Corrosion of reinforcement and chloride ion penetration rank high among factors that cause deterioration of concrete structures. This paper discusses these aspects and demonstrates the advantages of using GGBFS for producing durable construction. The paper also demonstrates that concrete with high volume GGBFS. where Portland cement becomes only the minor constituent of the cementitious system, possesses high performance qualities. The paper advocates a change in the concrete making industry towards substantial reduction in Portland cement that is to be met by equally substantial increase in the use of GGBFS.