Behaviour of G. I. fiber reinforced concrete made with natural and recycled aggregates

Abstract

The use of recycled aggregates from construction and demolition waste (CDW) as the replacement of coarse aggregates has increased in recent years in order to reduce the high consumption of natural resources by civil infrastructure construction sectors. In addition, steel fiber reinforced concrete has been used in many applications such as concrete pavements, overlays, patching repair of hydraulic structures, thin shells and precast products over the past several decades. Nowadays, it is well established that the incorporation of steel fibers improves engineering performance of structural and nonstructural concrete, including better crack resistance, increase in ductility and toughness as well as enhancement in resistance to fatigue and impact. In this work an experimental investigation is carried out to observe the influence of Galvanized Iron (G.I.) fiber reinforcement on the stress-strain behavior of concrete made with brick aggregate and recycled brick aggregate. In addition, compressive strength by destructive test as well as non-destructive test, Splitting tensile strength and Young’s modulus are also determined. Two types of coarse aggregates, brick and recycled brick aggregates having the same gradation and water cement ratio (w/c=0.44) are used. Hooked end G.I. wires with 50 mm of length and aspect ratio of 55.6 are used as fiber reinforcements in a volume fraction of 0%, 0.50% and 1.00%, respectively for the both cases. The experimental results show that around 10% to 15% and 40% to 60% increase in 28 days compressive strength and tensile strength of GI fiber reinforced concrete, respectively compared to control case (0% G.I. fiber replacement) for both the aggregates. It is seen that effect of addition of 1% fiber on the concrete compressive strength is little compared to that of 0.5% G.I. fiber addition for both the aggregate types. On the other hand, concrete strain at failure of G.I. fiber reinforced concrete has increased almost 2 times compared to the control case (0% GI fiber replacement) for both the aggregate types. It is also observed that effect of fiber reinforced concrete made with 1% fiber is more than 0.5% fiber for the both cases of aggregates in the terms of maximum strain of concrete. Keywords: Brick aggregate, Recycled Brick aggregate, G.I. fiber, Compressive strength, Tensile strength, Young’s Modulus, Stress-strain behavior.