Experimental Study of Self Compacting Concrete for Partial Replacement of Cement by Fly Ash and Silica Fumes

Abstract

The Self-Compacting Concrete (SCC) is that which gets compacted due to its self-weight and is deaerated (no entrapped air) almost completely while flowing in the form work. In recent times self-compacting concrete has been accepted as a quality product and are widely used. The addition of fly ash and silica fumes to concrete imparts superior mechanical properties to Self Compacting Concrete. The aim of this project work is to study the strength behavior of SCC partial replacement of cement with fly ash and silica fumes. Fly ash silica fume Self Compacting Concrete (FASFSCC) has been cast with volume fractions of 00%, 05%, 10% and 15% of silica fumes based on “Nan Su et.al” method and tested after 28 days of normal curing. This work also comprises the study of the effect of steel fibres on workability in fresh state and the compressive strength of cubes (150mmx150mmx150mm), split tensile strength of cylinders (diameter 150 mm and height 300mm), modulus of rupture of beams (100mmx100mmx500mm) in hardened state after 7,14, and 28 days of normal water curing. The results showed that the ultimate strength has increased marginally. The optimum volume fraction of silica fumes for better performance in terms of strength and ductility has been found to be 10%. Based on the results obtained from the investigations and after rational discussion, the conclusions have been developed on the fresh state properties of FASFSCC, hardened properties of FASFSCC, and the optimum dosage of silica fume.