Easy mixing and placement of concrete and ultimate performance of structural member regard to its cost is one of the important factor in concrete structures. This paper offers an innovative solution to enhance the workability of the core concrete of concrete filled steel tube (CFST) without using additives. This solution can be used for both passive and active CFTs. This study was performed in two phases. In the first phase, high performance concrete (HPC) mixture was introduced and compressive strength of this type of concrete was measured in order to investigate the efficiency of proposed mixture. In the second phase, the active and passive CFTs, with both conventional concrete (CC) and HPC mixtures were built and their flexural behavior was studied. The flexural capacity, energy absorption, flexibility and failure mode of the confined specimens as well as cracking pattern of the concrete core at the failure point are evaluated in this study. Obtained results showed the effectiveness of proposed method for concrete mixture design. HPC mixture not only increased the moment capacity and amount of absorbed energy of specimens but also changed the behavior of specimens. Moreover, this proposed HPC mixture was more effective for low compressive strength of the concrete core.
High performance concrete mixture, Fresh concrete, Active confinement, Passive confinement, flexural behaviour
 Lu, Y.Q., Kennedy, D. J. L., The Flexural Behavior of Concrete-Filled Hollow Structural Section, Canadian journal of civil engineering, Vol 21, No 1, 1994, pp. 111-130.
 Aaron, D., Thomas, H. K., Chris, R. and Uksun, K. , Composite Flexural Behavior of Full-Scale Concrete Filled Tubes without Axial Loads, Journal of structural engineering, 2010, 1401-1412.
 Elchalakani, M., Zhao, X. L., Grzebieta, R. H., Concrete-Filled Circular Steel Tubes Subjected to pure Bending, Journal of Constructional Steel Research, Vol 57, No 11, 2001, pp. 1141-68.
 Furlong, R. W., Strength of Steel-Encased Concrete Beam-Columns, Journal of Structural Division. ASCE, Vol 93, No ST5, 1967, pp. 113- 24.
 Prion, H. G. L., Boehme, J., Beam–Column Behavior of Steel Tubes Filled with High Strength Concrete. Canadian journal of civil engineering, Vol 21, No 2, 1994, pp. 207-218.
 Tomii, M., Sakino, K., Elasto-Plastic Behavior of Concrete Filled Square Steel Tubular Beam- Columns, Transactions of Architectural Institute of Japan, Vol 280, 1979, pp.111-20.
 Uy, B., Strength of Concrete Filled Steel Box Columns Incorporating Local Buckling, Journal of Structural Engineering. ASCE, Vol 126, No 3, 2000, pp. 341-52.
 Han, L. H., Flexural Behavoiur of Concrete- Filled Steel Tubes, Journal of Construction Steel research, Vol 60, No 2, 2004, pp. 313-37.
 Hosaka, T., Umehara, T., Nakamura, S., Nishiumi K., Design and Experiments on A New Railway Bridge System Using Concrete Filled Steel Pipes, ASCCS seminar. Concrete filled steel tubes. A comparison of international codes and practice. Innsbruck, Austria, 1997, pp. 367-372.
 Nakamura, S., Momiyama, Y., Hosaka, T. and Homma, K., New Technologies of Steel/Concrete Composite Bridges, Journal of civil engineering, Vol 58, 2002, pp. 99-130.
 Nematzadeh, M., Naghipour, M., Compressing Fresh Concrete Technique and the Effect of Excess Water Content on Physical-Mechanical Properties of Compressed Concrete, Materials and design, Vol 37, 2012, pp. 256-267.
 Nematzadeh, M., Naghipour, M., Compressive Strength and Modulus of Elasticity of Freshly Compressed Concrete. Construction and building materials, Vol 34, 2012, pp.476-485.
 Naghipour, M., Nemati, M., Jalali, J., Nematzadeh, M., The Effect of Active Confinement and shear key Elements on the Flexural Behavior of Concrete Filled Steel Tube (CFST), Journal of civil and environmental engineering, Vol 46.2, No 83, 2016, pp. 57-70.
 ACI 211.1-91 Committee, Standard practice for selecting proportions for normal, heavyweight, and mass concrete, ACI manual of concrete practice. part 1, Michigan (USA), American concrete institute. 38, 2000.
 AISC, Steel construction manual, American Institute of Steel Construction. 13th Ed., Chicago, 2005.
 ASTM C192 / C192M-16a, Standard Practice for Making and Curing Concrete Test Specimens in the Laboratory, ASTM International, West Conshohocken, PA, 2016, www.astm.org.
Cite this paper
Morteza Naghipour, Marzieh Nemati, Javad Jalali, Mahdi Nematzadeh. (2018) Effect of High Performance Concrete Mixture on Behavior of Passive and Active Confined CFT. International Journal of Theoretical and Applied Mechanics, 3, 17-25
Copyright © 2018 Author(s) retain the copyright of this article.
This article is published under the terms of the Creative Commons Attribution License 4.0