Study of Use of Bitumen Fiber to Increase Flexural Strength of Concrete

Since the time of World War, I there was increase in demand of development of blast resistance structure. It is during World War II the defense organizations took keen interest and funded the researchers carried on RCC structures subjected to blast loading [1]. The application of blast loading on structures affects the walls, columns, beams and slabs by impact waves. Therefore, a structural designer must ensure the failure of structure in ductile manner. The building constructed in Oklahoma City using non ductile concrete design proved to be extremely dangerous [2]. In high rise buildings due to decrease in wavelength the impact loading the time period increases. So, to reduce the effect of blast loading the size of the beam column is increased. Another approach to tackle the blast load is to add shear wall and bracings but as result the cost of the construction increases. Another way to reduce the effect is to use columns at closer distance at or near the ground. The columns are also sometimes wrapped with carbon fiber reinforced sheets, but it then affects the economy of the construction. Many researchers have shown in their research that the cost of construction of blast resistance of new structures is far overpriced than the cost required for retrofitting of a present structure to same standards [1]. The main damage mechanics of an explosion is supersonic shock waves that transmit radially from the blast origin like a bubble. The blast which occur at or near the earth’s surface, ground waves also take place and are handled similar to seismic waves [1]. The use high performance concrete (above M60) has added advantages over conventional concrete due to high compressive strength, low porosity, improved microstructural homogeneity, high flexibility with addition of fibers [3]. The design of high-grade concrete was made achievable by reduction of micro-cracks in the hydrated cement paste and the transition zone which results in reduction of porosity and reducing in homogeneity in the normal concrete [3].