Impact Toughness of Concrete Reinforcement Bars Produced by the THERMEX Process and Ordinary Rolling Process
Mohammad Sharear Kabir1, Md Moinul Islam2, Md Mohar Ali Bepari3
1Mohammad Sharear Kabir, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka Bangladesh.
2Md. Moinul Islam, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka Bangladesh.
3Md. Mohar Ali Bepari, Department of Materials and Metallurgical Engineering, Bangladesh University of Engineering and Technology, Dhaka Bangladesh.
Manuscript received on 10 July 2014 | Revised Manuscript received on 20 July 2014 | Manuscript Published on 30 July 2014 | PP: 53-59 | Volume-4 Issue-2, July 2014 | Retrieval Number: B1730074214/14©BEIESP
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© The Authors. Blue Eyes Intelligence Engineering and Sciences Publication (BEIESP). This is an open access article under the CC-BY-NC-ND license (http://creativecommons.org/licenses/by-nc-nd/4.0/)
Abstract: The impact toughness of rebars produced by the THERMEX process and ordinary rolling process was investigated by the Charpy impact test at temperatures between -400C and 1000C. The THERMEX process utilizes quenching and self-tempering technology during the final stages of rolling, whereas the ordinary rolling process does not. The rebars produced by the THERMEX process are known as quenched and self tempered rebars or QST rebars. A novel approach for testing impact toughness of QST rebars was implemented. The impact properties that were investigated comprised the total impact energy, ductile to brittle transition temperature (DBTT), transition temperature at 100% ductile fracture and transition temperature at 100% brittle/cleavage fracture. The QST rebars displayed much higher resistance to ductile fracture at high test temperatures, while its resistance to brittle fracture at low test temperatures was only a little higher than that of the ordinary hot rolled rebars. The QST rebars also displayed lower ductile to brittle transition temperature than the ordinary hot rolled rebar. This increase in the impact toughness of QST rebars can mostly be attributed to its composite microstructure consisting of a strong tempered martensite periphery/case and ductile ferrite-pearlite core.
Keywords: Ductile To Brittle Transition Temperature (DBTT), Impact Toughness, Quench And Self-Tempering, THERMEX Process.
Scope of the Article: Concrete Structures