ORCID Profile
0000-0002-2655-2466
Current Organisation
Ferdowsi University of Mashhad
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Publisher: American Society of Civil Engineers (ASCE)
Date: 10-2012
Publisher: Canadian Science Publishing
Date: 06-2005
DOI: 10.1139/L05-005
Abstract: This paper presents the results of an experimental study on bond strength of reinforcing bars made of glass fibre reinforced polymers (GFRP) embedded in normal and self-consolidating concrete. The study included pull-out tests of 36 GFRP reinforcing bars embedded in concrete specimens. Different parameters such as type of concrete, bar location, and cover thickness were considered as variables in different specimens. The results showed that the type of bond failure was by splitting of concrete for all specimens. The bond strength of bottom GFRP reinforcing bars was almost the same for both normal concrete and self-consolidating concrete. For the top bars, however, the bond strength of self-consolidating concrete was less than that of normal concrete.Key words: bond strength, glass FRP, reinforcing bars, top-bar effect, self-consolidating concrete.
Publisher: AIP
Date: 2008
DOI: 10.1063/1.2963780
Publisher: Elsevier BV
Date: 03-2019
Publisher: Elsevier BV
Date: 2008
Publisher: Elsevier BV
Date: 08-2019
Publisher: Elsevier BV
Date: 06-2000
Publisher: Elsevier BV
Date: 10-2020
Publisher: Elsevier BV
Date: 11-2008
Publisher: Elsevier BV
Date: 2017
Publisher: Informa UK Limited
Date: 02-07-2019
Publisher: CRC Press
Date: 07-07-2010
DOI: 10.1201/B10430-104
Publisher: Elsevier BV
Date: 10-2007
Publisher: Informa UK Limited
Date: 11-11-2019
Publisher: Elsevier BV
Date: 04-2009
Publisher: Springer Science and Business Media LLC
Date: 14-01-2019
Publisher: American Concrete Institute
Date: 1998
DOI: 10.14359/545
Publisher: Trans Tech Publications, Ltd.
Date: 26-09-2022
DOI: 10.4028/P-S2T9NL
Abstract: The main objective of this study was to investigate the influence of using magnetized water on the mechanical properties and durability behavior in terms of freeze-thaw resistance of recycled aggregate concrete. In addition to the effect of different numbers of water rounds in the magnetic field, other variables including steel fibers, super-plasticizers and silica-fume were considered in the concrete production in order to achieve the ideal possible performance for recycled aggregate concrete made with 100% coarse aggregates replacements. For this purpose, a total of 11 concrete mixes were prepared and tested. At the first step, the effects of the mentioned variables on the basic properties, including workability, water absorption, compressive strength, splitting tensile strength, flexural strength and freeze-thaw durability test were investigated. Additionally, flexural toughness was evaluated in accordance with the post-crack strength (PCS) method and the microstructure of concrete specimens was also observed by using scanning electron microscope (SEM). The results of most experiments indicated that magnetized water, although highly effective on the mechanical properties of concrete, should not be solely utilized as a compensating factor for the defects caused by recycled coarse aggregates. The optimum toughness and durability results regarding the fiber-reinforced concrete mixes produced with recycled coarse aggregates, were related to s les containing silica-fume and 10-rounds magnetized water. Furthermore, the existence of cement replaced by 10% of silica-fume and 10-rounds magnetized water in the concrete mix MW-SF2, increased the durability of the recycled aggregate concrete by an average of approximately 63%.
Publisher: SAGE Publications
Date: 18-02-2019
Publisher: Springer Science and Business Media LLC
Date: 23-07-2018
Publisher: Elsevier BV
Date: 02-2018
Publisher: Walter de Gruyter GmbH
Date: 2023
DOI: 10.1515/MT-2022-0210
Abstract: This paper investigates and compares the experimental results of fracture characteristics in various polypropylene fiber-reinforced concretes (high strength concrete, lightweight concrete, and engineered cementitious composite) on 90 three-point bend (notched and un-notched) beams. Five widely used fracture mechanics testing methods, such as work of fracture method, stress-displacement curve method, size effect method, J integral method, and ASTM E399, were used to investigate the fracture behavior. Results have demonstrated that fracture energy and fracture toughness improved as the dosage of polypropylene fibers increased in concretes. However, this improvement was different in concretes owing to various results of fracture mechanics testing methods and different properties of each concrete. Aggregates played significant role in the performance of polypropylene fibers on the fracture behavior of concretes. Among testing methods, the ASTM E399 showed the lowest values for the fracture toughness of concretes. Both work of fracture and stress-displacement curve methods exhibited appropriate results for the fracture energy of polypropylene fiber-reinforced concrete composites. The accuracy of size effect method was acceptable for determining size-independent fracture parameters of plain high strength and lightweight concretes. Furthermore, the J integral method showed more relevant results for the fracture toughness of polypropylene fiber-reinforced engineered cementitious composite.
Publisher: Elsevier BV
Date: 10-2020
Publisher: American Concrete Institute
Date: 2005
DOI: 10.14359/13527
Publisher: RILEM Publications
Date: 2006
Publisher: Canadian Science Publishing
Date: 07-2014
Abstract: In this paper, the flexural ductility of lap-spliced reinforced concrete (RC) beams is experimentally investigated. Twenty-four specimens were designed and manufactured for laboratory experiments. Concrete compressive strength, amount of transverse reinforcement over the splice length, and the diameter of longitudinal bars were selected as the main variables. The ductility of tested specimens is evaluated based on a previously defined ductility ratio. Results show that concrete strength and amount of transverse reinforcement over the splice have major effects on ductility. With an appropriate amount of transverse reinforcement, a satisfactory ductility response for different concrete strengths can be obtained. The CSA-A23.3-04 Standard provisions on bond strength and ductility of lap-spliced RC beams are evaluated and discussed. This study shows that the provisions in predicting the bond strength of lap-spliced concrete beams are adequate but may not achieve a satisfactory performance for ductility. An equation is proposed to achieve the appropriate ductility.
Publisher: Springer Science and Business Media LLC
Date: 15-07-2023
Publisher: American Society of Civil Engineers (ASCE)
Date: 06-2013
Publisher: Springer Science and Business Media LLC
Date: 02-02-2022
Publisher: WIT Press
Date: 09-05-2011
DOI: 10.2495/FSI110031
Publisher: SAGE Publications
Date: 30-09-2020
Abstract: This study presents a new method for strengthening the circular reinforced concrete (RC) column to foundation connections with shape memory alloy (SMA) bars and carbon fiber reinforced polymer (CFRP) sheets. In the experimental part of the study, three specimens of RC column-foundation connections were cast and tested. One specimen was used as the reference specimen without strengthening. Two other specimens were strengthened with longitudinal SMA bars and CFRP sheets. These specimens were under a constant axial compressive load and cyclic lateral displacements, simultaneously. Next, initial stiffness, energy dissipation capacity, lateral load capacity, ductility, and residual displacement of the specimens were investigated. Due to the superelastic behavior of SMA bars, the residual displacement of column-foundation connections was considerably less than that of the reference specimen. Compared to the reference specimen, the SMA-strengthened and SMA-CFRP-strengthened connections recovered 71.59% and 76.57% of the residual displacement. Therefore, SMA bars were able to recover residual displacements under cyclic loading. Also, the combination of the SMA bars with CFRP sheet was a promising solution for enhancing the amount of the energy dissipation, lateral load capacity, initial stiffness, and ductility parameters. Compared to the reference specimen, the energy dissipation, lateral load capacity, initial stiffness, and ductility ratio parameters of SMA-CFRP-strengthened connection increased about 43.45%, 76.20%, 81.69%, and 242.45%, respectively. In the numerical part of the study, a subroutine was applied for modeling the SMA materials. For the analysis, this subroutine was linked with ABAQUS software. The numerical results showed a close correlation with the experimental results.
Publisher: American Concrete Institute
Date: 1998
DOI: 10.14359/530
Publisher: Elsevier BV
Date: 09-2019
Publisher: Springer Science and Business Media LLC
Date: 17-01-2018
Publisher: Elsevier BV
Date: 07-2009
Publisher: Periodica Polytechnica Budapest University of Technology and Economics
Date: 30-01-2023
DOI: 10.3311/PPCI.21155
Abstract: The size effect on flexural properties and fracture behavior of polypropylene fiber-reinforced engineered cementitious composite (PPFECC) containing local waste materials was investigated. Geometrically similar notched beams with dimensions of 190 × 70 × 70 mm (small), 380 × 70 × 140 mm (medium), and 760 × 70 × 280 mm (large) were tested using three-point bending to study the size effect on flexural properties, toughness, and fracture behavior in PPFECC and the influence of tensile ductility of PPFECC on the size effect parameter. Two PPFECC mixtures containing 1% (PPFECC1) and 2% (PPFECC2) volume fraction of polypropylene fibers were prepared. The results indicated clear size effect on ductility, flexural strength, normalized deflection, normalized toughness, and fracture energy for both PPFECCs. The flexural properties and fracture behavior in PPFECC1 were more sensitive to the size effect parameter due to its lower tensile ductility compared to PPFECC2. Moreover, according to Bažant’s size effect curve, the behavior of notched beams in PPFECC2 with higher tensile ductility was closer to the strength criterion compared to PPFECC1.
Location: Iran (Islamic Republic of)
No related grants have been discovered for M. Reza Esfahani.