Durability studies on high strength concrete Plain concrete possesses a very low tensile strength, limited ductility and little resistance to cracking. Internal micro cracks are inherently present in the concrete and its poor tensile strength is due to the propagation of such micro cracks, eventually leading to brittle fracture of the concrete. It has been recognized that the addition of small, closely spaced and uniformly dispersed fibers to the concrete would act as crack arrester and would substantially improve its Compressive and flexural strength properties.Review: The concept of using fibers to improve the characteristics of construction materials is very old. Early applications include addition of straw to mud bricks, horse hair to reinforce plaster and asbestos to reinforce pottery. Use of continuous reinforcement in concrete (reinforced concrete) increases strength and ductility, but requires careful placement and labour skill. Alternatively, introduction of fibers in discrete form in plain or reinforced concrete may provide a better solution. The modern development of fiber reinforced concrete (FRC) started in the early sixtiesSteel FibersStraight, crimped, twisted, hooked, ringed, and paddled ends. Diameter rangefrom 0.25 to 0.76mm.Advantages: Increased tensile strength,flexural rigidity,toughness. More resistance to first crack,corrosion.Applications: Refractories,pavements,overlays,patching,flooring,bridge decking, caissons,car parks,pipes,poles,repairs of dams,machine bases frames,manhole covers. Durability Tests: Sulphate resistance,acid resistance,permeability,chloride resistance

Date:10/21/2014 ( Signature of project guide