http://www.iaeme.com/IJCIET/index.asp 349 editor@iaeme.com International Journal of Civil Engineering and Technology (IJCIET) Volume 9, Issue 2, February 2018, pp. 349–360, Article ID: IJCIET_09_02_034 Available online at http://http://www.iaeme.com/ijciet/issues.asp?JType=IJCIET&VType=9&IType=2 ISSN Print: 0976-6308 and ISSN Online: 0976-6316 © IAEME Publication Scopus Indexed BEHAVIOR OF NORMAL, HIGH AND ULTRA- HIGH STRENGTH CONCRETE IN DIRECT SHEAR Dr. Qassim Ali Al-Quraishy Doctor, Lecturer, Civil Engineering Department, AL-Mansour University College, Baghdad, Iraq ABSTRACT The construction and manufacture of high buildings and the increasing demands of owners and designers have directed to the increasing and growing demand for “high” and "ultra-high strength" (HSC and UHSC) concrete. This innovative concrete technology was designated with extremely high (f'c) compressive strength. This paper displays and presents an experimental work that focuses on structural performance in relevant to the shear load with the inclusion of mode of failure and final strength. Direct shear samples with an inverted "L" shape has been tested to the shear failure level using "normal", "high", and "ultra-high-strength" concrete with the impact of steel fibers. The test (shear strength test) taken here, where are the sample preparation and testing process can be simpler and through the same corresponding and particular time guarantees steady and compatible results. The experimental search results and conclusions display that the steel fiber samples exhibit a ductile manner with the improvement in the ultimate strength, in counting, and significantly improve in structural integrity. The variants that were considered were compressive strength (f'c) and steel fiber (vf) volume fraction. It was discovered that the addition and inclusion of steel fiber enhance and improve the ultimate shear capacity and capability of the concrete compared to conventional plain concrete. Key words: Normal, high, ultra-high, shear strength and steel fiber. Cite this Article: Dr. Qassim Ali Al-Quraishy, Behavior of Normal, High and Ultra- High Strength Concrete in Direct Shear. International Journal of Civil Engineering and Technology, 9(2), 2018, pp. 349-360. http://www.iaeme.com/IJCIET/issues.asp?JType=IJCIET&VType=9&IType=2 1. INTRODUCTION High strength (HSC) and ultra-high-strength (UHSC) concrete is generally and commonly used with a compressive strength (f'c) greater than (100 MPa) [Dili, A. S. and Manu Santhanam, (2004), Wille, K. et. al., (2011), A. Logan, et. al., (2009)]. These types of concrete are considered and recognized to be nearly and comparatively as a brittle behavior material. Ultra-high strength (UHSC) concrete is a concrete that has a very low ratio of water to cement, high binder content, and optimal packing density to eliminate capillary pores and