Study of Early Age Properties and Behaviour of Concrete with GGBS as Partial Replacement of Cement

Abstract

Ground granulated blast furnace slag (GGBS) is used as alternative binder material for cement in the concrete. The use of GGBS in concrete production contributes to the saving of natural resources and energy spent in cement manufacturing process and also to reduce CO₂ emissions and environmental impact. In this research, GGBS is used as binder material for Ordinary Portland Cement in concrete by replacing cement up to 45% by weight of cementitious material. This investigation is carried out to study the fresh properties, early age strength properties and mechanical properties such as compressive strength of concrete specimen by partial replacement of cement with GGBS up to 45% and compared with referral mix. A total of four concrete mix proportion (NC, Mix 1-15%, Mix 2-30%, Mix 3- 45%) with and without GGBS were made. The compression test were carried out to determine the strength properties of concrete at the age of 3 days, 7days and 28 days. The test result shows that the 28days compressive strength at 15 % GGBS content for M35 and M40 grade of concrete is comparable with referral mix. It is observed that concrete made with GGBS have lower strength at early ages, but gain strength more steadily than equivalent concrete made with Portland cement which is having higher early age strength but does not rise rapidly on the later stages. The M40 grade concrete has better workability when compared with M35 grade concrete.