Cementing Efficiency of Rice Husk Ash and Ground Granulated Blast Furnace Slag in M60 grade Self Compacting Concrete

This paper enumerates strength gain efficiency of Rice Husk Ash (Rha) and Ground Granulated Blast Furnace Slag (Gbbfs) blend in Self-Compacting Concrete (SCC). From the precious studies carried by the authors it was observed that optimal use of Rha+Ggbfs in low and medium strength concretes imparts initial strengths and also later strengths. In low and medium strength SCC mixes, Ggbfs replaces OPC optimally (30%) and Rha replaces Ggbfs optimally (3%) but in case of high strength SCC mixes, RHA replacing Ggbfs does not offer the required workability or strength so instead of replacing Ggbfs by certain amount, Rha is added to the SCC. It was found that GGBFS does not yield the required workability so RHA is added to GGBFS based SCC. So after various trial mixes it was found that 25% GGBFS by weight of OPC and 5% RHA by weight of GGHFS is added to OPC. It was observed that 5% RHA addition to OPC made with 25% Ggbfs gives desired workability and strength. Due to addition of GGBFS to SCC will enhance the later age compressive strength but early age compressive strength decreases while the desired workability is controlled using SP appropriately. In M60 GGBFS+RHA based SCC, the strength increase at 3 days is nearly 33% and the compressive strength at 28 days decreased by 10%. Similarly tensile strength in a GGBFS and RHA admixed SCC increases by around 27% in M60 grade.