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    Shear behavior of ultra-high performance concrete

    , Article Construction and Building Materials ; Volume 183 , 2018 , Pages 554-564 ; 09500618 (ISSN) Pourbaba, M ; Joghataie, A ; Mirmiran, A ; Sharif University of Technology
    Elsevier Ltd  2018
    Abstract
    The application of ultra-high performance concrete (UHPC) as an alternative to conventional/normal concrete (NC) has grown rapidly in recent years. However, there is limited knowledge on its shear behavior, which is essential for developing design guidelines for structural applications. A detailed parametric study was conducted on 38 beam specimens, half of which were made of UHPC and the other half made of NC. To ensure applicability of findings, two types of UHPC mixes were used, a proprietary and a generic mix. Eighteen of the beams were prepared and tested in Tabriz, Iran, while the other 20 were made and tested in Miami, FL. Test parameters included type of concrete (UHPC and NC), shear... 

    Use of Polymer Fibers Recovered from Waste Timing Belts in High Performance Concrete

    , M.Sc. Thesis Sharif University of Technology Esrafili, Amin (Author) ; Khalu, Alireza (Supervisor)
    Abstract
    The present paper discusses the possibility of adding recycled polymer fibres to high performance concrete (HPC). Fibres used in this study were recovered from discarded car timing belts. To investigate different characteristics of the concrete specimens several destructive and non-destructive tests, such as compressive strength, modulus of rupture, flexural toughness, ultrasonic velocity and electrical resistance tests were carried out. In addition, slump flow tests were conducted on the fresh concrete. Experimental results from the study showed that the use of low percentages (up to 0.5%) of waste fibres improved the modulus of rupture and flexural toughness. Based on ultrasonic and... 

    Shear Capacity of Ultra-High Performance Concrete Rectangular Beams

    , Ph.D. Dissertation Sharif University of Technology Pourbaba, Masoud (Author) ; Joghataie, Abdolreza (Supervisor)
    Abstract
    The application of ultra-high performance concrete (UHPC) as an alternative to conventional/ normal concrete (NC) has grown rapidly in recent years. However, there is limited knowledge on its shear behavior, which is essential for developing design guidelines for structural applications. A detailed parametric study was conducted on 38 beam specimens, half of which were made of UHPC and the other half made of NC. To ensure applicability of findings, two types of UHPC mixes were used, a proprietary and a generic mix. Eighteen of the beams were prepared and tested in Tabriz, Iran, while the other 20 were made and tested in Miami, FL. Test parameters included type of concrete (UHPC and NC),... 

    Casting Method Development and Characteristics Enhancement of High Performance Concrete by Utilization of Nano-SiO2 Particles and Different Types of Fibers

    , Ph.D. Dissertation Sharif University of Technology Mobini, Mohammad Hossein (Author) ; Khaloo, Alireza (Supervisor)
    Abstract
    The aim of this study was to evaluate the effects of applying low replacement ratios (0.75% and 1.50% of the binder weight) of nano-SiO2 particles with different specific surface areas (200 and 380 m2/g) on the properties of high-performance concrete (HPC). Mechanical (compressive and splitting tensile strengths), electrical resistivity, non-destructive (ultrasonic pulse velocity), and microstructural (mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy) tests were conducted to investigate the macroscopic and microscopic effects of nano-SiO2 particles on HPC characteristics. The results indicated that the performance of nano-SiO2 particles significantly... 

    An investigation on the effect of cement and silica fume on properties of self-compacting concrete

    , Article Proceedings of the 13th East Asia-Pacific Conference on Structural Engineering and Construction, EASEC 2013 ; September , 2013 Moshiri, F ; Atashnama, A ; Panahi, M ; Gharebaghi, R ; Mahlouji, J ; Sharif University of Technology
    Hokkaido University collection of Scholarly Academic Papers, HUSCAP  2013
    Abstract
    Self-Compacting concrete (SCC) is identified as a high performance concrete with the ability of self compaction, using its own weight without any external vibration. SCC is able to fill congested area and voids, even in highly reinforced concrete members whilst it flows without segregation. The fresh properties of SCC such as workability can be determined using different tests including slump-flow, J ring, V-funnel, U box, L box, GTM and column technique. In this paper the effect of different amount of cementitious material, silica fume and W/C ratios on workability and compressive strength of SCC are investigated. The results indicate that the workability of mixtures is reduced by... 

    Modeling of compressive strength of HPC mixes using a combined algorithm of genetic programming and orthogonal least squares

    , Article Structural Engineering and Mechanics ; Volume 36, Issue 2 , 2010 , Pages 225-241 ; 12254568 (ISSN) Mousavi, S. M ; Gandomi, A. H ; Alavi, A. H ; Vesalimahmood, M ; Sharif University of Technology
    2010
    Abstract
    In this study, a hybrid search algorithm combining genetic programming with orthogonal least squares (GP/OLS) is utilized to generate prediction models for compressive strength of high performance concrete (HPC) mixes. The GP/OLS models are developed based on a comprehensive database containing 1133 experimental test results obtained from previously published papers. A multiple least squares regression (LSR) analysis is performed to benchmark the GP/OLS models. A subsequent parametric study is carried out to verify the validity of the models. The results indicate that the proposed models are effectively capable of evaluating the compressive strength of HPC mixes. The derived formulas are... 

    Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes

    , Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) Pourbaba, M ; Joghataie, A ; Sharif University of Technology
    Sharif University of Technology  2019
    Abstract
    In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the... 

    Determining shear capacity of ultra-high performance concrete beams by experiments and comparison with codes

    , Article Scientia Iranica ; Volume 26, Issue 1A , 2019 , Pages 273-282 ; 10263098 (ISSN) Pourbaba, M ; Joghataie, A ; Sharif University of Technology
    Sharif University of Technology  2019
    Abstract
    In this research, 19 specimens of ultra-high performance fiber-reinforced concrete rectangular beams were made and their shear resistance was determined experimentally. The results were compared with estimations by ACI 318, RILEM TC 162-TDF, Australian guideline, and Iranian national building regulations. To compare the code estimations, the ratio of experimental shear strength to predicted shear strength was calculated for each code. This ratio is in fact a measure of safety factor on the one hand and a measure of precision of the estimation on the other hand. Based on the results of both studies, the authors concluded that the Australian guideline, with the amount of 2.5, provided the... 

    Flexural behavior of concrete beams reinforced with high volume steel fibers

    , Article ISEC 2013 - 7th International Structural Engineering and Construction Conference: New Developments in Structural Engineering and Construction ; 2013 , Pages 1031-1036 ; 9810753551 (ISBN) ; 9789810753559 (ISBN) Khaloo, A ; Jahromi, H. S ; Mohammadian, A ; Yazdani S ; Singh A ; Sharif University of Technology
    2013
    Abstract
    This paper presents the results of an experimental study on the flexural behavior of ten 10 × 15 × 120 (cm) steel reinforced high strength concrete beams under deflection control loading conditions. Test variable includes volumetric percentage of steel fibers (0%, 1.5%, 3%, 4%, 5%). The plain concrete strength was 30MPa. The monotonic concentrated load was applied at the center of the beam, the relative deflection was measured, and demec points were used to determine curvature of the beam. Load-deflection and moment-curvature diagrams have been obtained and plotted for each beam individually. Test results indicate that higher fiber content considerably improves flexural behavior and provides... 

    Mechanical properties of fiber-reinforced high-performance concrete incorporating pyrogenic nanosilica with different surface areas

    , Article Construction and Building Materials ; Volume 101 , December , 2015 , Pages 130-140 ; 09500618 (ISSN) Mobini, M. H ; Khaloo, A ; Hosseini, P ; Esrafili, A ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    The aim of the present study was to investigate the effect of pyrogenic nanosilica with different specific surfaces areas (200 and 380 m2/g) on mechanical properties of fiber-reinforced high-performance concrete (FRHPC) produced with two different types of fibers including steel and polypropylene fibers. Accordingly, different mechanical tests (compressive, splitting tensile and flexural strengths) as well as electrical resistivity were performed at 7, 28, and 91 curing days. In addition, the modulus of rupture and flexural toughness of FRHPC prisms were calculated based on the flexural testing results. Also, scanning electron microscopy test (SEM) was conducted to evaluate the... 

    Use of polymer fibres recovered from waste car timing belts in high performance concrete

    , Article Construction and Building Materials ; Volume 80 , April , 2015 , Pages 31-37 ; 09500618 (ISSN) Khaloo, A. R ; Esrafili, A ; Kalani, M ; Mobini, M. H ; Sharif University of Technology
    Elsevier Ltd  2015
    Abstract
    The present paper discusses the possibility of adding recycled polymer fibres to high performance concrete (HPC). Fibres used in this study were recovered from discarded car timing belts. To investigate different characteristics of the concrete specimens several destructive and non-destructive tests, such as compressive strength, modulus of rupture, flexural toughness, ultrasonic velocity and electrical resistance tests were carried out. In addition, slump flow tests were conducted on the fresh concrete. Experimental results from the study showed that the use of low percentages (up to 0.5%) of waste fibres improved the modulus of rupture and flexural toughness. Based on ultrasonic and... 

    Influence of different types of nano-SiO2 particles on properties of high-performance concrete

    , Article Construction and Building Materials ; Volume 113 , 2016 , Pages 188-201 ; 09500618 (ISSN) Khaloo, A ; Mobini, M. H ; Hosseini, P ; Sharif University of Technology
    Elsevier Ltd  2016
    Abstract
    The aim of this study was to evaluate the effects of applying low replacement ratios (0.75% and 1.50% of the binder weight) of nano-SiO2 particles with different specific surface areas (200 and 380 m2/g) on the properties of high-performance concrete (HPC). Mechanical (compressive and splitting tensile strengths), electrical resistivity, non-destructive (ultrasonic pulse velocity), and microstructural (mercury intrusion porosimetry, X-ray diffraction, and scanning electron microscopy) tests were conducted to investigate the macroscopic and microscopic effects of nano-SiO2 particles on HPC characteristics. The results indicated that the performance of nano-SiO2 particles significantly... 

    Experimental investigation on effects of hybrid fibers on rheological, mechanical, and durability properties of high-strength SCC

    , Article Construction and Building Materials ; Volume 147 , 2017 , Pages 497-509 ; 09500618 (ISSN) Tabatabaeian, M ; Khaloo, A ; Joshaghani, A ; Hajibandeh, E ; Sharif University of Technology
    Abstract
    The aim of the present study is to investigate the effects of using hybrid fibers on rheological, mechanical and durability properties of the high-strength self-consolidating concrete (SCC). For this purpose, two types of fibers including hooked-end steel fibers and polypropylene fibers were used. In this study, a total of eleven mixtures were used: one as a control mix, one containing 0.5% steel fibers, four containing 0.5% hybrid fibers (steel and polypropylene), one containing 1.0% steel fibers and the four containing 1.0% hybrid fibers (steel and polypropylene). For investigating the rheological properties, slump flow, J-ring and V-funnel tests were performed. Mechanical properties were... 

    Fracture properties of steel fiber reinforced high strength concrete using work of fracture and size effect methods

    , Article Construction and Building Materials ; Volume 142 , 2017 , Pages 482-489 ; 09500618 (ISSN) Kazemi, M. T ; Golsorkhtabar, H ; Beygi, M. H. A ; Gholamitabar, M ; Sharif University of Technology
    Elsevier Ltd  2017
    Abstract
    This paper deals with investigation of fracture behavior of steel fiber reinforced high strength concrete (SFRHSC) and compare it to plain high strength concrete (HSC). Based on an experimental program, a series of three point bending tests were carried out on 54 notched beams, as recommended by RILEM. The fracture parameters were measured by two methods: work of fracture method (WFM) and size effect method (SEM). Then the fracture parameters obtained from these two methods were compared. The results showed that with increase of steel fibers, fracture energy of GF in WFM and Gf in SEM increase but this increase in work of fracture method is more significant. The effective size of the process... 

    Green high strength concrete containing recycled waste ceramic aggregates and waste carpet fibers: Mechanical, durability, and microstructural properties

    , Article Journal of Building Engineering ; Volume 26 , 2019 ; 23527102 (ISSN) Zareei, S. A ; Ameri, F ; Bahrami, N ; Shoaei, P ; Musaeei, H. R ; Nurian, F ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    This paper investigated the combined utilization of recycled waste ceramic aggregate (RWCA) and waste carpet fibers (WCFs) in high strength concrete (HSC). Concrete mixes containing different percentages of RWCA including 20%, 40%, 60% (by weight) as partial replacement of natural coarse aggregate (NCA) were prepared. To enhance the tensile and flexural strength of concrete, 1.0% (by volume) WCF was added to the mixes. The slump and density of the fresh concrete were evaluated, both of which demonstrated a decreasing trend with incorporation of RWCA and WCF. With regard to the hardened concrete, replacing 40% of NCA with RWCA led to the optimum mechanical properties and increased the... 

    Performance of sustainable high strength concrete with basic oxygen steel-making (BOS)slag and nano-silica

    , Article Journal of Building Engineering ; Volume 25 , 2019 ; 23527102 (ISSN) Zareei, S. A ; Ameri, F ; Bahrami, N ; Shoaei, P ; Moosaei, H. R ; Salemi, N ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    This study presents the results of an experimental evaluation of the performance of high strength concrete (HSC)with basic oxygen steel-making (BOS)slag and nano-silica respectively used as a partial replacement of sand and cement. The properties of fresh and hardened concrete specimens containing 25%, 50%, 75%, and 100% BOS as partial replacement of sand and 2% of cement replaced with nano-silica were evaluated. According to the results, concrete samples containing nano-silica with higher BOS percentages, demonstrated improvements in strength and durability properties, while workability was reduced. For example, at 50% BOS content, about 18% increase in compressive strength and 50%... 

    Recycled ceramic waste high strength concrete containing wollastonite particles and micro-silica: A comprehensive experimental study

    , Article Construction and Building Materials ; Volume 201 , 2019 , Pages 11-32 ; 09500618 (ISSN) Zareei, S. A ; Ameri, F ; Shoaei, P ; Bahrami, N ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    This study investigated the effects of combined utilization of wollastonite particles and recycled waste ceramic aggregate (RWCA) on high strength concrete (HSC) properties. Two groups of mixtures were manufactured: 1) concrete mixtures in which cement was partially replaced with wollastonite at values ranging from 10% to 50%, and 2) mixtures in which wollastonite was used at the aforementioned dosages and 50% of natural coarse aggregate was replaced with RWCA. In addition, 10% of cement weight micro-silica was added to all mixtures. The concrete behavior in terms of strength, durability, resistance against acidic environment, and performance under elevated temperatures ranging from 20 °C to... 

    Experimental investigation on freeze-thaw durability of polymer concrete

    , Article Frontiers of Structural and Civil Engineering ; Volume 15, Issue 4 , 2021 , Pages 1038-1046 ; 20952430 (ISSN) Jafari, K ; Heidarnezhad, F ; Moammer, O ; Jarrah, M ; Sharif University of Technology
    Higher Education Press Limited Company  2021
    Abstract
    Assessing the durability of concrete is of prime importance to provide an adequate service life and reduce the repairing cost of structures. Freeze-thaw is one such test that indicates the ability of concrete to last a long time without a significant loss in its performance. In this study, the freeze-thaw resistance of polymer concrete containing different polymer contents was explored and compared to various conventional cement concretes. Concretes’ fresh and hardened properties were assessed for their workability, air content, and compressive strength. The mass loss, length change, dynamic modulus of elasticity, and residual compressive strength were determined for all types of concretes... 

    Fiber bridging in polypropylene-reinforced high-strength concrete: An experimental and numerical survey

    , Article Structural Concrete ; 2021 ; 14644177 (ISSN) Khaloo, A ; Daneshyar, A ; Rezaei, B ; Fartash, A ; Sharif University of Technology
    John Wiley and Sons Inc  2021
    Abstract
    Fracture process of fiber-reinforced concrete notched beams is investigated here. Polypropylene macrosynthetic fibers are utilized for reinforcing concrete specimens, and a high-strength mix design is used to produce strong bonds between the embossed polypropylene fibers and the cementitious matrix of beams. Considering different locations for the notch, this study focuses on bridging mechanism under different conditions using both experimental and numerical approaches. First mode of fracture occurs due to opening of crack faces. This mode of failure is simulated by imposing symmetric boundary conditions on middle-notched beams. Inducing the notch with an offset from the middle, mixed-mode... 

    An innovative high performance pervious concrete with polyester and epoxy resins

    , Article Construction and Building Materials ; Volume 228 , 2019 ; 09500618 (ISSN) Tabatabaeian, M ; Khaloo, A ; Khaloo, H ; Sharif University of Technology
    Elsevier Ltd  2019
    Abstract
    Pervious concrete (PC) has been detecting application in pavement and concrete structures such as dams, small retaining walls, and etc during the past decades. Also, in recent years, the types of resins have been introduced to apply in concrete owing to the enhancing in mechanical and durability characteristics. However, few studies have investigated the mechanical behavior of high performance pervious concrete (HPPC) incorporated by polyester and epoxy resins as polymeric composites, where ordinary cement material has been completely deleted. The purpose of this investigation is to compare the mechanical properties, permeability, and durability of HPPCs made by polymeric composites (i.e....