[Ahmed, 3(12): December, 2014] ISSN: 2277-9655 Scientific Journal Impact Factor: 3.449 (ISRA), Impact Factor: 2.114 http: // www.ijesrt.com © International Journal of Engineering Sciences & Research Technology [646] IJESRT INTERNATIONAL JOURNAL OF ENGINEERING SCIENCES & RESEARCH TECHNOLOGY Experimental Study on Torsion of Steel Fiber Reinforced Concrete Members with Ternary Blended Concrete Omer Zaheer Ahmed*, Mohd Zaker Dept of Civil Engineering, Osmania University, Hyderabad, India Dept of Civil Engineering , Jawaharlal Nehru Technological, University, Hyderabad, India Abstract The study on the torsional behavior of concrete in which the effect of fiber reinforcement in resisting twisting of concrete beams and performance of concrete with ternary blends. When silica fume is added to fresh concrete it chemically reacts with the CH gel to produces additional CSH gel. The benefit of this reaction is twofold increased compressive strength and chemical resistance. The hydration (mixing with water) of Portland cement produces many compounds, including calcium silicate hydrates (CSH) and calcium hydroxide (CH). The CSH gel is known to be the source of strength in concrete. It is noted that the silica fume has better result when the cement replaced with it by 6% to 8% by weight. Fly ash in the mix replaces Portland cement, producing big savings in concrete materials costs. Fly ash is an environmentally-friendly solution that enhances the performance of concrete. Hence, this work is carried out with different combination of fibers with the inclusion of two admixtures to form ternary blended concrete to find out maximum torsional carrying capacity and to achieve the optimum fiber combination for Ternary Blended Fiber Reinforced Concrete Beams. In the present experiment programme standard cubes (150x150x150mm) standard beams (1300x100x100mm) long and (200x100x100) arms at both ends were casted and tested for finding the torsional strength property of plain cement concrete and ternary blended steel fiber reinforced concrete. The compressive strength of control concrete (ordinary concrete),Ternary concrete contain 6% Micro silica and 15% Fly ash and ternary blended fiber reinforced concrete with various percentages of fibers concrete specimens having W/C 0.40, were tested. Results obtained from experimental investigation to study the torsional strength of ternary blended fiber reinforced concrete are presented here for discussion; the torsional strength of ternary blended fiber reinforced concrete is compared with the ternary blended concrete. There is a considerable improvement in the compressive strength of concrete with 6% replacement of cement by micro silica and 15% replacement of fly ash along with 1.25% addition of steel fibers, because of the high Pozzolanic nature of the condense micro silica, fly ash and its void filling ability. Keywords: Steel fiber reinforced concrete (SFRC), silica fume, Ternary blended, ultimate torsion strength, longitudinal reinforcement . Introduction Torsion occurs more frequently in most structures but rarely occurs alone. However, torsion forms one of the basic structural actions besides flexure, shear and axial compression/tension. Torsional failure of concrete members is initiated by the tensile stress developed due to a state of pure shear, which arises due to torsion. Inclusion of steel fibers principally may increase the tensile strength of the matrix to a moderate level but the toughness will be enhanced to a greater extent. This particular advantage of fiber reinforced concrete inspired the researchers to study its mechanical properties under different conditions of loading. But little information is available on the behavior of fiber reinforced concrete members under pure torsion. Earlier investigations indicated that the addition of fibers improves the torsional strength and ductility of member in this investigation an attempt has been made to quantify the effect of fibers in resisting torsional loads. Effects of ternary cement system The combination of micro silica and fly ash in a ternary cement system (i.e., Portland cement being the third component) should result in a number of synergistic effects, some of which are obvious or intuitive, as follows: Micro silica compensates for low early strength of concrete with low CaO fly ash. Fly ash increases