This project it has carried out torsional strength for reinforced concrete elements by using sisal fibers. In last around 3 decades, all over the world are finding out potential applications of a natural fiber base reinforced concrete based element. So many countries research and the investigation was carried out to find the various physical and also mechanical properties, the durability of such products reinforced with natural organic fibers. Since last some years, various researchers investigated the use of fibers in construction materials like mortar, concrete etc. However, all properties of concrete may not improve for the same proportions of the different combination. Mechanical behavior of fiber reinforced concrete composite depends on the structure of composite both, properties of concrete and properties of type fiber used in a mix. Hence, for analysis and prediction about the performance of composite at different loading condition, the internal structure of composite must be characterized.