American Journal of Civil Engineering 2013; 1(3): 102-110 Published online November 10, 2013 (http://www.sciencepublishinggroup.com/j/ajce) doi: 10.11648/j.ajce.20130103.14 The effect of steel fiber on some mechanical properties of self compacting concrete Abbas AL-Ameeri Civil, Engineering/ University of Babylon, Babylon City, Iraq Email address: abb68abb21@yahoo.com To cite this article: Abbas AL-Ameeri. The Effect of Steel Fiber on Some Mechanical Properties of Self Compacting Concrete. American Journal of Civil Engineering. Vol. 1, No. 3, 2013, pp. 102-110. doi: 10.11648/j.ajce.20130103.14 Abstract: Self compacting concrete (SCC) is compacting itself alone due to its self-weight and is filled almost completely while flowing in the formwork. In structural members with high percentage of reinforcement ,it fills also completely all voids and gaps. The purpose of presented research is to investigate, the fresh properties of Steel Fiber SCC and the hardened properties. Fresh properties comprising flow ability, passing ability, and viscosity related segregation resistance. Hardened properties comprising compressive strength, splitting tensile strength, flexural strength, modulus of elasticity, and Ultrasonic pulse velocity. The results indicated of the fresh properties of SCC with steel fiber , reduction in workability with increase of steel fiber content. Also the Steel fibers had effect on compressive & tensile strength , modulus of elasticity and ultrasonic pulse velocity of steel fiber self compacting concrete, there was an optimum content of steel fiber at which higher performance obtained at the both mentioned characteristics ,the content was(0.75- 1)% . All fiber mixes demonstrated higher splitting tensile strength, and flexural strength relative to plain mix at all curing ages. The strengths increased as the fiber content increased. The fibers slightly decrease the U.P.V followed the same behavior as in compressive strength of SCC. Keywords: Steel Fiber, Compressive Strength, Tensile Strength, Flexural Strength, Modulus of Elasticity 1. Introduction The Self compacting concrete (SCC) is a concrete which has the ability to flow by its own weight and achieve good compaction without external vibration. In addition, SCC has good resistance to segregation and bleeding because of its cohesive properties [1]. The raw material selection is an important part of the mix design process for SCC, since it will significantly influence the stability as well as the cost of the mix, which are two key elements in the successful use of SCC. There is no standard method for SCC mix design ,but many academic institutions, admixture ready-mix, precast and contracting companies have developed their own mix proportioning methods. Mix designs often use volume as a key parameter because of the importance of the need to over fill the voids between the aggregate particles. Some methods try to fit available constituents to an optimized grading envelope (European Project Group, 2005) [2]. Mix designs of SCC must satisfy the criteria on filling ability, passing ability and segregation resistance. The most common method of mix design is the general method developed by the University of Tokyo and since then, many attempts have been made to modify this method to suit local conditions [3] .In general, the following rules should be followed to be successful in manufacturing SCC ,with certain methods are used [4],there are many methods for design of mixes such as Rational methods [5],and EFNARC methods [2]. SCC is known to be brittle and can easily crack under low levels of tensile force. Inherently Plain, unreinforced concrete is a brittle material, with a low tensile load and a low strain capacity. This behavior of brittleness can be overcome by using randomly oriented short discrete fibers. Fibers not only suppress the formation of cracks, but also abate their propagation and growth. Fibers have been added to hardened state. Fiber reinforced concrete becomes an option whenever durability (limited crack widths) or safety considerations are design criteria. They improve the performance (strength and toughness) of brittle cement-based materials by bridging cracks, transmitting stress across a crack and counteracting the crack growth [6].The steel fiber is the most common fiber type in the building industry; plastic, glass and carbon fibers contribute to a smaller part to the market [7]. There are various types of steel fibers such as wave cut, end large steel fiber, deformed sheet and also hooked end steel fiber. In