The Effects of Bi-Combination of GGBS and PFA on the Mechanical Properties of Concrete

The main thrust of the current study is to examine the effects of ground granulated blast-furnace slag (GGBS), pulverized fuel ash (PFA), and bi-combination of GGBS and PFA on the mechanical properties of concrete. Seven concrete mixes were carried out in this study; including the control mix and the other six mixes had supplementary cementitious materials (GGBS, and PFA) as partial replacement of Portland cement at different replacement levels. The physical properties, oxides, and chemical composition of OPC, GGBS and PFA were experimentally investigated. The workability of the fresh concrete mixes was carried out by means of slump test and compaction index test. This study also examined the compressive strength of the different concrete mixes at different curing ages along with the splitting tensile strength. Cost analysis and the environmental impact of the different concrete mixes was also evaluated. The study results showed that the workability was significantly improved through the replacement of cement with PFA and GGBS. The utilisation of fly ash at 30% replacement level achieved the highest workability. The highest compressive strength was achieved by concrete mixes replacing 30% GGBS with cement, and a bi-combination of 10% PFA and 20% GGBS. The results also showed that the bi-combination of fly ash and GGBS at 10% and 20% replacement level was found to be favorable in terms of both cost and environmental impact.