R.Karthi, Dr. P. Chandrasekaran M.E., Ph.D.,
Now a day’s high strength and high performance concrete are being widely used all over the world. Most applications of high strength concrete have been in high rise buildings, long span bridges and in some special applications in structures. In developed countries, using high strength concrete in structures today would result in both technical and economic advantage. In high strength concrete, it is necessary to reduce the water/cement ratio and which in general increases the cement content. To overcome low workability problem, different kinds of mineral admixtures (fly ash, rice husk ash, silica fume etc.) and chemical admixtures are used to achieve the required workability. In the present experimental investigation, the mechanical properties of high-strength concrete of grades M60, at 28 days characteristic strength with different replacement levels of cement with silica fume are considered. Standard cubes (150mm x 150mm x 150mm), standard cylinders (150mm dia x 300mm height) and standard prisms (100mm x 100mm x500mm) were considered in the investigation. all specimens were cast with and without polypropylene fiber. The mechanical properties viz., compressive strength, flexural strength and split tensile strength, of high strength concrete with various replacement of polypropylene fiber 0.5%, 1%, 1.5% and 2% and silica fume viz., 10%, 20%, and 30% , has been considered. The study revealed that the use of waste material like silica fume improved the mechanical properties of high strength concrete, which is otherwise hazardous to the environment and thus may be used as a partial replacement of cement