Experimental Investigation to Study the Properties of Concrete Incorporated with GGBS and GBS

Abstract

In the present study, mix design ingredients viz. water, cement, ground granulated blast-furnace slag (GGBS), aggregate (fine and coarse), ground blast-furnace slag (GBS) and chemical admixture were collected, tested and the findings are presented in this paper for Joda and Khondbond Iron Mines Expansion Project, Orrisa for Tata Steel Limited. Tata Steel Group is implementing ground granulated BF slag (GGBS + GBS) in its entire construction project sites after preparing a proper mix design. Compatibility (complex interaction between cement [1,2,3] and chemical admixtures [4]) may be issued because of the large variation of fine contents during the trials. Due to incompatibility between cement and chemical admixtures, concrete may face various problems during the concreting works viz. late setting of concrete, fast slump loss/moisture loss, inadequate strength increase, cracking, etc. These problems may affect the properties of fresh and hardened concrete viz. primary strength and durability. Compatibility between GGBS blended cement and chemical superplasticizer (IS: 9103) was confirmed by Marsh cone test. Considering the compressive strength of cement mortar, setting time of concrete, workability, compressive strength and durability (measured in terms of rapid chloride penetration test (RCPT)) and the mix design for M30 grade of concrete were prepared with 40% replacement of cement by GGBS and 25% replacement of sand by GBS. During the course of trials/study, the main objective was to find the effect of fines (GGBS + GBS) content on the properties of concrete. Many research papers have been published pertaining to GGBS utilization/properties but GGBS + GBS concrete is rarely seen after recent advancement in IS 383 pertaining to the uses of aggregate from unconventional sources.