Development of Reinforced Concrete Beam with Plastic Balls in Neutral Axis

Concrete is one of the most widely used construction material. Its usage is twice that of steel, wood, plastics and aluminium combined. It provides superior fire resistance compared with wooden construction and gains strength over time. Structures made of concrete can have a long service life. The major drawback in concrete works is that the structures will be heavier. In case of RC beams the strength of concrete lying in and near the neutral axis is not fully utilized. So this unutilized concrete is replaced by light weight plastic balls. This is an alternative to reduce the use of concrete. Plastics offer great resistance against chemicals and solvents. The concrete just above the neutral axis is less stressed where as the concrete below neutral axis serves as a shear transmitting media. Plastic material offers a good bond between concrete layers. The stresses in beams are maximum at top and bottom where as, it is zero at the neutral axis. The cement content can also be decreased by saving the concrete which reduces the greenhouse gaseous emissions. So it is considered as eco-friendly. Specimens of solid RC beam, hollow RC beam and RC beam with plastic balls are casted, tested and made a comparison.