Publisher: TULPAR Academic Publishing   (Total: 2 journals)   [Sort by number of followers]

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Challenge J. of Concrete Research Letters     Open Access   (Followers: 4)
Challenge J. of Structural Mechanics     Open Access   (Followers: 7)
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Challenge Journal of Concrete Research Letters
Number of Followers: 4  

  This is an Open Access Journal Open Access journal
ISSN (Online) 2548-0928
Published by TULPAR Academic Publishing Homepage  [2 journals]
  • Cover & Contents Vol.13 No.4

    • Authors: Journal Management CJCRL
      PubDate: 2022-12-13
      Issue No: Vol. 13, No. 4 (2022)
  • Effect of steam‒curing on the glass fiber reinforced concrete

    • Authors: Mehmet Canbaz, Mouad Bensaoud, Hakan Erol, Hasan Selim Şengel
      Pages: 107 - 115
      Abstract: Due to the increased need to use precast concrete to reduce construction duration and to accelerate the cement reaction process to achieve the required concrete resistance that enables the elements to gain the required strength to handle the loads generated by the transportation process, many companies use steam curing methods to expedite the hydration process. The steam curing process negatively affects the concrete strength, especially in the long term. Fibers of different types are used to improve the interior composition of concrete and increase its crack resistance. The purpose of the current study was to determine the effect of the glass fiber on the behavior of steam-cured concrete. In this study 90 concrete cubes were used with 15cm dimensions, three different weight ratios of glass fibers (0%, 0.12%, and 0.24%) with two curing methods standard curing in the water tank (water curing - WC) for 3, 7, and 28 days, and steam curing (SC) for 4 and 8 hours. Nine specimens of each mix were cast in 12 mm, and 24 mm fibers length and tested for each curing duration and method. The results of this study indicate that fiber glass addition to the steam-cured concrete has a positive effect on the concrete unit weight and the ultrasonic pulse velocity. Moreover, the result showed that the tensile and compressive strength of the concrete has been positively affected by the length of the fiber more than the fiber weight percentage.
      PubDate: 2022-12-13
      DOI: 10.20528/cjcrl.2022.04.001
      Issue No: Vol. 13, No. 4 (2022)
  • Economical evaluation of reinforced concrete hospital construction cost
           using bottom ash and fly ash

    • Authors: Burak Oz, Memduh Karalar, Murat Çavuşli
      Pages: 116 - 126
      Abstract: The use of waste materials in nature (e.g. fly ash, bottom ash) in the construction phase of buildings is of great importance both in terms of environmental pollution and the construction cost of the structures. Therefore, in this study, the effects of bottom ash and fly ash on the construction cost of reinforced concrete (RC) hospital buildings are investigated by considering experimental tests and 3D nonlinear analyzes. During the experiments, four different concrete series are created and fly ash and bottom ash are added to replace 0–5 mm grain size aggregates in the concrete mixture at different ratios. The RC beams created according to four different concrete series are subjected to experimental tests. Afterward, it is determined that the most critical mixing ratio for RC beams subjected to experimental tests is selected as 75% bottom ash ratio and fly ash. For the purpose Ankara Bilkent City Hospital is selected for 3D nonlinear seismic analyses and the hospital structure is subjected to 10 various earthquake analyses. This study showed that there was a noticeable decrease in the construction cost when the costs of the hospital structure were compared as a result of the earthquake analysis. Another important point is that the use of bottom ash and fly ash is thought to contribute to savings in the energy to be used for the storage of wastes by causing less electrical energy use in cement production, less greenhouse gas emissions, natural raw material consumption and nature pollution.
      PubDate: 2022-12-13
      DOI: 10.20528/cjcrl.2022.04.002
      Issue No: Vol. 13, No. 4 (2022)
  • Effects of fibers geometry and strength on the mechanical behavior and
           permeability properties of slurry infiltrated fiber concrete (SIFCON)

    • Authors: Fatih Özalp
      Pages: 127 - 136
      Abstract: The use of slurry-infiltrated fiber concrete (SIFCON) has been increasing in recent years. SIFCON is a very good alternative, especially in structural reinforcement processes. In this study, the effects of 2 different steel fibers of normal strength (3D) and high strength (5D) with different geometry and strength properties and polyolefin origin synthetic fiber are examined on the mechanical behavior and capillary water permeability properties of SIFCON. Steel fibers were used in 2 different ratios by volume 4% and 8%, while polyolefin synthetic fiber was used at 4% by volume. The bending strength and splitting tensile strength of SIFCON containing 5D steel fiber are 46.47 MPa and 18.47 MPa, respectively, 4.9 and 2.1 times higher than plain concrete. In addition, the fracture energy of SIFCON containing 5D steel fiber is 20400 N/m, and it is 358 times higher than plain concrete, 1.6 and 3.1 times higher than concrete containing the same amount of 3D fiber and polyolefin synthetic fiber, respectively. The capillary water absorption of SIFCON, which contains 4% synthetic fiber and 8% 3D steel fiber by volume, is 0.121 mm and 0.112 mm, respectively, which is higher than all other mixtures in the study. As a result of the study, higher splitting tensile strength, bending strength and fracture energy values were obtained in concretes containing 5D steel fiber, which have high tensile strength and have better adhesion to concrete due to its geometry. The use of synthetic fibers or high amounts of steel fibers increased the permeability. 
      PubDate: 2022-12-13
      DOI: 10.20528/cjcrl.2022.04.003
      Issue No: Vol. 13, No. 4 (2022)
  • Cover & Contents Vol.13 No.3

    • Authors: Journal Management CJCRL
      PubDate: 2022-09-29
      Issue No: Vol. 13, No. 3 (2022)
  • Assessing effects of waste coal bottom ash on construction cost of
           reinforced concrete structures considering experimental data

    • Authors: Memduh Karalar, Burak Öz, Murat Çavuşli
      Pages: 80 - 92
      Abstract: In this study, it has been examined whether the bottom ash (BA) released to the nature as waste material from the thermal power plant can be used in reinforced concrete structures (RCS) and how much cost reduction will be caused in construction technology if BA is used in RCS. For this purpose, coal BA produced by Turkey-Zonguldak Cates power plant is mixed in different ratios into the concrete mixture of the beams. The different coal bottom ash ratio (BAR) is used instead of aggregate in the mixture. The beams created for 5 different BARs are subjected to tests and it is observed that the beam with the most critical bending is the beam with 75% coal BA. This BAR is applied to bearing elements of finite element model (FEM) and then current cost of the building and the construction cost used 75% coal BAR are compared with each other. It has been observed that when 75% coal BAR is used instead of aggregate in RCSs, there is a 40% reduction in construction costs. This result is of great importance both for the recycling of BA and for revealing that BA reduces construction costs.
      PubDate: 2022-09-29
      DOI: 10.20528/cjcrl.2022.03.001
      Issue No: Vol. 13, No. 3 (2022)
  • Mechanical behavior investigation of rubberized concrete barriers in
           impact load

    • Authors: Hasan Selim Şengel, Ahmet Şahin Özgören, Hakan Erol, Mehmet Canbaz
      Pages: 93 - 100
      Abstract: Approximately 1.5 million waste tires are produced annually. Waste tires in landfills and stocks cause toxic chemicals to pollute the soil and cause major fires. Waste tires are a global environmental problem. This problem gave an idea of recycling of waste tires instead of landfills and stocks. In this paper, an experimental study is conducted to review the behavior under impact load of rubberized concrete with conventional concrete. Three different mixes were made by adding crumb rubber (0%, 5% and 10%) by volume to the concrete. Nine cantilever column specimens of three type cross section (10x10, 15x15 and 20x20 cm2) were used to investigate the behavior under impact load. The specimens with higher rubberized concrete have longer impact load duration at the initial peak point. Specimens with rubber content become much flexible than normal specimens. Furthermore, the damage level of columns is greater with increasing rubber content. Therefore, the specimens with higher rubberized concrete absorb more impact energy. The barriers with higher rubber content minimize injury and demise when an accidental impact happens. Using concrete with rubber content reduces costs and produces an environmentally sustainable solution.
      PubDate: 2022-09-29
      DOI: 10.20528/cjcrl.2022.03.002
      Issue No: Vol. 13, No. 3 (2022)
  • Effect of waste concrete powder on slag-based sustainable geopolymer
           composite mortars

    • Authors: Erdinç Halis Alakara, Özer Sevim, İlhami Demir, Gazi Günel
      Pages: 101 - 106
      Abstract: In this study, the effect of waste concrete powder (WCP) on slag-based geopolymer composite mortars was investigated. Blast furnace slag (BFS) and WCP were used as binders in geopolymer mortars. WCP was substituted into the geopolymer mortar composites at rates of 10%, 20%, 30%, and 40% by weight of slag. Sodium hydroxide (NaOH) solution was used as the alkali activator in the mixtures and the solution activator concentration was chosen as 16 molars (M). After the prepared mortars were cured at 100°C for 24 hours, they were subjected to flexural strength (ffs), compressive strength (fcs), and ultrasonic pulse velocity (UPV) tests. When the obtained results were examined, it was observed that ffs, fcs, and UPV results decreased with the increase in WCP replacement ratio. These decrements were seen clearly, especially after the 20% replacement ratio. However, despite these decrements, the compressive strengths of all groups were found to be above 50 MPa. In addition, it is thought that environmental pollution can be reduced by using WCP in geopolymer composite mortars.
      PubDate: 2022-09-29
      DOI: 10.20528/cjcrl.2022.03.003
      Issue No: Vol. 13, No. 3 (2022)
  • Cover & Contents Vol.13 No.2

    • Authors: Journal Management CJCRL
      PubDate: 2022-06-06
      Issue No: Vol. 13, No. 2 (2022)
  • Effect of curing time on polymer concrete strength

    • Authors: Ferit Cakir
      Pages: 54 - 61
      Abstract: With the advancement of polymer technology, polymer concrete (PC) has become increasingly popular throughout the world and it has among the major construction materials due to its many advantages. The strength and durability of PCs are directly related to paste quality and curing time. The curing time is of the utmost importance to ensure desirable mechanical properties. An understanding of the strength-time relationship of PCs is crucial to understanding the effects of loading on concrete at an older age. The objective of this paper is to study the behavior of PC under different curing times with an emphasis on compressive and flexural strengths. Therefore, a total of 63 specimens were tested at seven different ages (1 day, 3 days, 5 days, 7 days, 14 days, 28 days, and 105 days) throughout the study. According to the results obtained from the tests, it is shown that the curing time plays a critical role in the flexural and compressive strengths of PCs. PCs gain more than 80% of their mechanical strength within three days, and the long-term strength does not change significantly after seven days.
      PubDate: 2022-06-06
      DOI: 10.20528/cjcrl.2022.02.001
      Issue No: Vol. 13, No. 2 (2022)
  • Research on micro limestone for concrete pavements produced with natural
           aggregates in the Erzurum region

    • Authors: Ali Öz
      Pages: 62 - 71
      Abstract: The use of naturally formed aggregates in concrete pavements is an innovative and sustainable solution both environmentally and economically. This study investigates the usability of fine and coarse aggregates formed spontaneously in Oltu, Narman, Pasinler and Uzundere in concrete pavements by improving the mechanical properties of concrete. In the study, the compressive strength, flexural strength, water absorption capacity and capillarity permeability of the concrete samples planned to be used on concrete pavements were obtained by considering the contribution of these aggregates. In addition, microscopic electron scanning analyzes (SEM) were applied to visualize the internal cracks that may occur in the concrete. The test results showed that the concrete formed with aggregates from Oltu and Pasinler regions had the highest compressive, flexural and hardened unit weights. It has been concluded that the concrete produced from Uzundere region, which gives results below 35 MPa in terms of compressive strength, is not applicable on concrete pavements. In addition, considering the high compressive, flexural, unit weight and capillary permeability, it is predicted that the most suitable concrete design for the construction of concrete pavements is the P0 (concrete formed with aggregates from Pasinler region) concrete sample.
      PubDate: 2022-06-06
      DOI: 10.20528/cjcrl.2022.02.002
      Issue No: Vol. 13, No. 2 (2022)
  • Minimum weight design of reinforced concrete beams utilizing grey wolf and
           backtracking search optimization algorithms

    • Authors: Osman Tunca, Serdar Çarbaş
      Pages: 72 - 79
      Abstract: In this study, optimal weight design of a reinforced concrete beam subjected to various loading conditions is investigated. The purpose of the optimization is to attain the minimum weight design of the reinforced concrete beam under distributed and two-point loads. The design problem is handled under three different design load cases. The two-point loads are affected on beam-to-beam connection nodes of reinforced concrete beams. Thus, while the magnitudes of distributed load and two-points load are remained constant, the distances between two-points loads are taken as 2m, 3m and 4m, respectively. The width and height of the rectangular cross-section of the concrete beam, and the diameters of the longitudinal and confinement steel rebars are treated as design variables of the optimum design problem. The design constraints of the optimization problem consist of the geometric constraints and necessities of the Turkish Requirements for Design and Construction of Reinforced Concrete Structures (TS500), and Turkish Building Earthquake Code (TBEC). As two novel metaheuristics, grey wolf (GW) and backtracking search (BS) optimization algorithms are selected as optimizers. Both algorithms are independently operated five times for three different design problems. Thus, the obtained results are examined statistically to compare in accordance with algorithmic performances. The optimal findings from optimization algorithms show that the GW algorithm is a little bit more robust on the exploitation phase, while the BS algorithm is stronger on the exploration phase. Moreover, it can be deducted from optimal beam designs that the GW algorithm is more viable to minimize reinforced concrete beam design.
      PubDate: 2022-06-06
      DOI: 10.20528/cjcrl.2022.02.003
      Issue No: Vol. 13, No. 2 (2022)
  • Cover & Contents Vol.13 No.1

    • Authors: CJCRL Journal Management
      PubDate: 2022-03-24
      Issue No: Vol. 13, No. 1 (2022)
  • Optimization of axial load carrying capacity of CFST stub columns

    • Authors: Celal Çakıroğlu, Gebrail Bekdaş
      Pages: 1 - 4
      Abstract: Concrete filled steel tubular (CFST) columns are widely used due to their enhanced mechanical properties. The interaction between the concrete core and the steel casing increases structural stability and magnifies the compressive strength of concrete. Besides the structural performance, in alignment with the commitment of the concrete industry to reduce its environmental impact, lowering the carbon emissions caused by the production of concrete structures is gaining importance in recent years. The current paper gives an overview of the equations available in the literature that predict the axial load carrying capacity of rectangular CFST columns. A modified version of the Jaya metaheuristic algorithm is being proposed and the outcome of this algorithm is being presented. The algorithm is used in order to maximize the axial load-carrying capacity of a stub column. As an optimization constraint the CO2 emission associated with the production of the CFST column is being kept below a predefined level throughout the optimization process. The optimization process as well as the cross-sectional dimensions associated with the optimum solution are presented.
      PubDate: 2022-03-24
      DOI: 10.20528/cjcrl.2022.01.001
      Issue No: Vol. 13, No. 1 (2022)
  • Structural behavior of ferrocement composite hollow-cored panels for roof

    • Authors: Yousry B. I. Shaheen, Zeinab A. Etman, Aya M. Elrefy
      Pages: 5 - 27
      Abstract: The main objective of the following work is to study the effect of using different types of metallic and non-metallic mesh reinforcement materials on the flexural behavior of ferrocement hollow-cored panels as a viable alternative for conventional reinforced concrete roofs. The proposed panels are lighter in weight relative to the conventional reinforced concrete panels. Three types of the steel meshes were used to reinforce the ferrocement skin layers. Namely: welded wire mesh, expanded metal mesh, and tenax mesh with various numbers of layers. Experimental investigation was conducted on the proposed panels. A total of ten slabs having the total dimensions of 2000 mm length, 500 mm width and 120 mm thickness were cast and tested under flexural loadings until failure. The deformation characteristics and cracking behavior were recorded and observed for each panel at all stages of loadings. The results showed that high ultimate and serviceability loads, crack resistance control, high ductility, and good energy absorption properties could be achieved by using the proposed panels. This could be of true construction merits for both developed and developing countries alike. The experimental results were then compared to analytical models using (ABAQUS/Explicit) programs. The finite element (FE) simulations achieved better results in comparison with the experimental results.
      PubDate: 2022-03-24
      DOI: 10.20528/cjcrl.2022.01.002
      Issue No: Vol. 13, No. 1 (2022)
  • Effect of expanded polystyrene beads on the properties of foam concrete
           containing polypropylene fiber

    • Authors: Mehmet Canbaz, Ali Can Türeyen
      Pages: 28 - 35
      Abstract: In this study, foam concrete was produced using 3 different volumes of EPS beads (up to 100%), 3 different volumes of polypropylene(PP) fiber (up to 0.1)%, sand and 40% pre-produced foam which is fixed by volume. The water-cement ratio was 0.4 and the sand-cement ratio was chosen as 1. The foam concrete were cast into molds with a size of 100 x 100 x 500 mm and 150 x 150 x 150 mm prism. Unit weight, ultrasonic pulse, water absorption, splitting tensile strength, bending strength and compressive strength tests were achieved. Foam concrete were kept in laboratory standard conditions. According to the results of study, unit weight and ultrasonic pulse velocity vary between 970-1350 kg/m3 and 1.6-2.6 km/sec, respectively. The water absorption of the foam concrete decreased up to 65% as the EPS beads ratio increased. Since EPS beads do not contribute to the strength and act like a void, splitting tensile strength in specimens containing EPS beads decreased by up to 70%. The use of fiber contributes to the splitting tensile strength, especially in specimens that do not contain EPS beads, and it increased the strength by 78%. Similarly, the flexural strength of the PP fiber addition increased by up to 70%. As the EPS beads ratio increased, the flexural strengths decreased by 77%. With the addition of PP fiber, the compressive strength increased by 55%. However, since EPS beads' strength is negligible, it caused a 60% decrease in compressive strength.
      PubDate: 2022-03-24
      DOI: 10.20528/cjcrl.2022.01.003
      Issue No: Vol. 13, No. 1 (2022)
  • Effect and optimization of incorporation of nano-SiO2 into cement-based
           materials – a review

    • Authors: Mohammed Gamal Al-Hagri, Mahmud Sami Döndüren
      Pages: 36 - 53
      Abstract: Incorporation of nanomaterials into cement-based materials has great potentials to improve their performance to great levels and to produce construction materials with superior and unique properties. Various nanoparticles have been utilized in cementitious composites to improve their properties. This paper provides a detailed review about the effect of the most widely incorporated nanomaterial into cement-based materials, namely nano-silica, on different on properties of cement-based materials. The investigated properties are mechanical properties (compressive strength, split tensile strength and flexural strength), durability parameters (permeability, freeze and thaw resistance, high temperature resistance, fire resistance and sulfate attack resistance) and microstructural properties of mortar and concrete. The cost effectiveness of use of nano-silica in cement-based materials is also discussed. The optimum replacement percentage of cement with this nanomaterial to improve the performance of mortar and concrete is also investigated. The investigation showed that nano-silica has the ability to enhance the mechanical properties, durability and microstructural properties of concrete and mortar to a remarkable level. It also showed that the optimum content of nano-silica in concrete and mortar is 1.0-4.0% by weight of binder materials.
      PubDate: 2022-03-24
      DOI: 10.20528/cjcrl.2022.01.004
      Issue No: Vol. 13, No. 1 (2022)
School of Mathematical and Computer Sciences
Heriot-Watt University
Edinburgh, EH14 4AS, UK
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