Effects of induction furnace slag on the durability properties of concrete

Abstract

In this study, three major properties of concrete were compared, viz: water absorption, compressive strength and chloride ion penetration. The percentage amounts of Induction furnace slag (IFS) varied in concrete to replace cement were 0%, 5%, 10%, 15%, 20%, 25%, 30%, 35%, 40%, 45%, 50%, 55% and 60%. These specimens were made to undergo curing for 7, 14, 28, 56 and 90 days following which the aforementioned tests took place. The results of the three tests (i.e. compressive strength test, water absorption test and chloride ion penetration test) showed an optimal performance of concrete at 25% IFS replacement. Some of the specimens containing varying amounts of slag (i.e. 0%, 25% and 45%) were subjected to microstructural and phase identification tests in other to establish their distinguishing properties. These tests include Scanning Electron Microscopy (SEM) and X-ray Diffraction (XRD). Meanwhile the IFS was also examined for its composition through X-ray Fluorescence (XRF). Predictive models were generated from all the results obtained. The models developed can predict the compressive strength of concrete (Y) if information on the percentage of IFS replaced (X1), the depth of chloride ion penetration into concrete (X2) and the amount of void left in concrete after water is absorbed (X3) are all known. There existed a high correlation; strong relationship between compressive strength and the depth of chloride ion penetration; and between compressive strength and the percentage volume of void.