Influence of GGBS on rheology of cement paste and concrete with SNF and PCE based Superplasticizers

Abstract

Limestone and clay which are the major ingredients of the cement production are non-renewable resources. Therefore, it isessential to identify a sustainable material to replace cement. The by-product from the steel plant is subsequently granulatedto desired fineness and is termed as Ground Granulated Blast furnace Slag (GGBS). Superplasticizers (SP) are used to improvethe workability of concrete at low water-cement ratios and increase the compressive strength by reducing it. But, this work-ability is sometimes lost rapidly as time progresses after contact between the cement and water. Therefore, it is necessaryto understand the mechanisms that influence the cement-super plasticizer interaction for selecting an appropriate type of admixture at an optimum dosage. In this present research the compatibility study, between six combinations of cement us-ing different percentages of GGBS with two different SPs were investigated. The optimum dosage was found using marshcone test. The cement mortar flow test was conducted to find out the setting time and compressive strength of the mortar. Itis found that the increase in addition of GGBS decreases the dosage of Superplasticizers to achieve the desired workability. The target mean strength of the M40 concrete was achieved with replacement of 50% GGBS using PCE based SP.