Life Science Journal 2013;10(12s) http://www.lifesciencesite.com http://www.lifesciencesite.com lifesciencej@gmail.com 934 Concrete reinforced with 0.1 vol% of different synthetic fibers Anwar Khitab 1 , Muhammad Tausif Arshad 2 , Nazakat Hussain 3 , Kashan Tariq 4 , Syed Amir Ali 5 , Syed Minhaj Saleem Kazmi 6 , Muhammad Junaid Munir 7 1,2,3,4,6,7 Department of Civil Engineering, Mirpur University of Science and Technology, Azad Kashmir, Pakistan 5 Council for Works & Housing Research, Karachi, Pakistan anwarkhitab@yahoo.com , chairman.ce@must.edu.pk Abstract: This paper documents the effect of fibers type on different physical and mechanical properties of concrete. Four types of fibers, such as steel, polypropylene, glass, and carbon were investigated. The concrete specimens with and without fibers were cast and tested to watch the improvement of certain mechanical and physical properties like compressive, tensile strengths, workability and density. Fibers were added at the rate of 0.1 vol percent of concrete, while all the other ingredients were kept same at identical laboratory conditions. It was observed that type of fiber has huge impact on the workability of the concrete. Only steel fibers enhance the density of concrete, It was also found that the given fiber dosage enhances the early compressive strength of concrete but reduces the 28 days compressive strength. Steel fibers increase the tensile strength more than any other fiber used during this study. It was noticed that addition of fibers in concrete largely improves the failure pattern of the concrete subjected to compressive loads. [Anwar Khitab, Muhammad Tausif Arshad, Nazakat Hussain, Kashan Tariq, Syed Amir Ali, Syed Minhaj Saleem Kazmi, Muhammad Junaid Munir. Concrete reinforced with 0.1 vol% of different synthetic fibers. Life Sci J 2013;10(12s):934-939] (ISSN:1097-8135). http://www.lifesciencesite.com . 152 Keywords: Concrete, fibers, type, effect, physical properties, mechanical properties, failure pattern. 1. Introduction Concrete is a composite and brittle material that totally loses its loading capability, once failure starts. This deficiency of concrete can be overcome by adding discrete fibers (Song and Hwang, 2004). Together with fibers, the concrete is known as Fiber reinforced concrete abbreviated as FRC. FRC has found its applications in commercial, residential and hydraulic structures. At present, different materials like steel, glass, polypropylene, nylon, carbon and various natural materials like coconut and horsehair are being employed in concrete to make FRCs . The most popular among these are the steel fibers, followed by polypropylene, nylon, glass and carbon (Banthia, 2012 and Stevens, 1995). According to American Concrete Institute, steel fibers meant for concrete reinforcement are short, discrete lengths of steel of any cross section having an aspect ratio of 20- 100 (ACI, 1996). Steel fiber reinforced concrete often abbreviated as SFRC displays much better performance than the same concrete without any fiber. Its compressive, tensile and flexural strengths are much higher (Banthia, 2012). That's why SFRC is frequently being used in slabs subjected to high traffic loads. Apart from steel fibers, numerous researchers from all over the world have also worked on other fiber-reinforced concretes and have suggested that mechanical properties of fiber reinforced concrete are much superior than the ordinary concrete (Zahra et al. 2014 and Song et al. 2005). They have reported that the brittleness and the low tensile strength associated with an ordinary concrete can be overcome by adding fibers (Vikrant at al., 2012). Fibers also prevent the development of cracks and show unique post-cracking performance before failure. While making FRC, it is vital that the fibers should be uniformly distributed throughout the concrete mix (Brown et al., 2012). The present work presents a comparative investigation among the synthetic fibers mentioned above. Fiber reinforced concrete specimens having same quantity of different synthetic fibers were investigated. As mentioned in the abstract, all fibers were added @ 0.1 vol% of concrete. The idea of fiber-reinforcement in construction materials is very old. Straw and horsehair were used in lime mortar and clayey tiles. In the beginning of the last century, asbestos fibers were incorporated for the first time in concrete. Knowing the health risks associated with asbestos (Nicholson et al., 1982), the use of asbestos fibers was abandoned. By 1970s, steel, glass, and synthetic fibers such as polypropylene and nylon fibers were explored for concrete (Sridhara et al., 1971). Search of new fibers for concrete continues even today. The popularity of FRCs lies in the fact that they tender special characteristics like crack-arrest and enhanced strengths, which are not possible to attain with ordinary concrete (Barzin, 2012). In the following, a brief introduction of the fibers, studied during the present project is presented. Hard Carbon Steel Fibers are being used in concrete since decades (Banthia, 2012). Although, not a replacement of the reinforcement bars, the use of