EFFECTS OF GGBFS TO THE COMPRESSIVE STRENGTH, WORKABILITY AND TIME SPAN BETWEEN MIXING AND COMPACTING OF CONCRETE PASTE

This paper investigated the effect of GGBFS to the concrete compressive strength, workability and also time span between mixing and compacting of concrete paste. It used 480 concrete cylinder specimens consist of 240 specimens for normal concrete and 240 specimens of 2 hours mixing concrete varied in the percentage of GGBFS replacing levels, concrete grades, ages and also water-cement ratio. Results found that the optimum replacement level of GGBFS is 40% indicated by the highest compressive strength of both normal and two hours mixing time. The workability of concrete paste increases by the increasing replacement level of GGBFS. However this workability values have to be checked using the Standard.