Effects of utilising granulated blast furnace slag as fine aggregate on concrete: a factorial design approach

The present study evaluates the effect of utilising granulated blast furnace slag as a partial substitution of the fine fraction of natural aggregates on various concrete parameters using the general factorial approach. Two levels of the water/cement ratio (0.45 and 0.5) and four different percentages of granulated blast furnace slag (0, 20%, 40% and 60%) have been considered for this purpose. In addition to this, 7, 28, 90 and 365 days compressive strength, flexural and split tensile strength, and rebound number have been chosen as responses. Analysis of results of this study depicts that enhancement in water/cement ratio from 0.45 to 0.5 reduces the compressive strength, tensile strength and rebound number. Further, the responses of the study improve considerably with the alternation of granulated blast furnace slag (%) from zero to 60. Examining the outcomes of the analysis of variance and the main effect plots of chosen responses depicts that the selected factors have substantial influences on the compressive strength, tensile strength and rebound number of concrete mixes. However, critical assessment of the interaction plot and analysis of variance test results exhibit that the interaction of water/cement ratio and granulated blast furnace slag (%) has no significant influence on the aforementioned concrete parameters.