Effect of Length of Fibers on Mechanical Properties of Normal Strength Concrete

Abstract

Concrete as the most common building material possess very less tensile strength. To overcome this problem, different types of fibers are added with concrete matrix from from the ancient era. Investigation of fiber reinforced concrete reveals that short length fibers help in bridging micro cracks while long fibers are able to arrest macro cracks and also enhance toughness of the member. The combinations of different lengths of fibers are found to be more effective than mono length fibers for a fixed volume fraction of fiber. Combination of different lengths of fibers is termed as hybrid fiber and when different lengths of fibers are mixed in concrete it is termed as graded fiber. This investigation aims in finding out the enhancement of mechanical properties of a particular grade of concrete with addition of different lengths of fibers and with graded fiber with a fixed amount of fiber. M30 grade concrete with 1.5% weight of fiber is considered in this present investigation. The results shows that the mechanical strength of concrete increases with addition of fibers, decreases with long length of fibers with same volume fraction of fiber and increases with graded fiber. Workability decreases with addition of fiber, with higher length of fiber. There is enhancement of workability with graded fiber than same volume fraction of long fibers.