AN EXPERIMENTAL STUDY ON PARTIAL REPLACEMENT OF CEMENT BY GGBS

Concrete is the most world widely used construction material with about 6 billion tones being produced every year. In terms of per capita consumption, it comes next to water. The extraction of raw materials and emission of CO2 during cement manufacture cause great damage to the environmental sustainability. So, it becomes the need to reduce cement consumption. It can be done by partially replacing the cement by supplementary materials without compromising with strength and durability characteristics of the concrete. These materials may be naturally occurring, industrial wastes or by-products that are less energy extensive. These pozzolanic materials when combined with calcium hydroxide, exhibits cementitious properties. Most commonly used pozzolanic materials are fly ash, metakaolin, silica fume, ground granulated blast furnce slag (GGBS). It needs to examine the admixtures performance when blended with concrete so as to ensure required strength, durability and reduced lifecycle cost. The present paper focuses on investigating characteristics of M35 grade concrete with partial replacement of cement with GGBS by 30%, 40% and 50%. The cubes and beams are tested for compressive strength and flexural strength respectively. From the experimental investigation, it was found that as the GGBS replacement level increased the workability increased. Also, both compressive strength and flexural strength of concrete increased as the GGBS content increased up to 40% but they decreased as the GGBS content increased above 40%. It was also found that both maximum compressive strength and maximum flexural strength of the concrete were achieved at 40% GGBS replacement level. So, the optimum content of GGBS for compressive strength and flexural strength is 40%.