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Challenge Journal of Concrete Research Letters
Number of Followers: 3

This is an Open Access Journal

Open Access journal
ISSN (Online) 2548-0928
Published by TULPAR Academic Publishing

[2 journals]

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
construction
- 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)
Cover & Contents Vol.12 No.4
- Authors: Journal Management CJCRL
  PubDate: 2021-12-16
  Issue No: Vol. 12, No. 4 (2021)
Ballistic strength of aerated concrete
- Authors: Gökhan Durmuş, Sefa Ekinci
  Pages: 114 - 124
  Abstract: In regional studies conducted by the Law Enforcement Agency and the Armed Forces within the scope of counter-terrorism activities, to ensure peace and security throughout the country and for the police and military personnel to provide security services, the need to produce different solutions has arisen in the face of attacks on the security points established at many important points, especially at the entrance and exit points of the cities. In this context, by changing the direction and angle of the wall types made of aerated concrete used in construction techniques, 7 variations were tested on these wall types with materials formed with adhesive mortar+plaster, monolithic elastomer polyurea, and non-Newtonian fluid, and the strength of these materials were tested with BR6 and BR7 bullets. The main purpose of this study was to determine the most suitable material in terms of security parameters in the shortest time and at a low cost and to create a reliable structure for security cabins. At the end of the study, the best results were obtained with the shots made on the narrow surface of the aerated concrete and the shots made on the platform formed with non-Newtonian fluid.
  PubDate: 2021-12-16
  DOI: 10.20528/cjcrl.2021.04.001
  Issue No: Vol. 12, No. 4 (2021)
Effects of dry particle coating with nano- and microparticles on early
compressive strength of portland cement pastes
- Authors: Hediye Yorulmaz, Sümeyye Özuzun, Burak Uzal, Serhan İlkentapar, Uğur Durak, Okan Karahan, Cengiz Duran Atiş
  Pages: 125 - 130
  Abstract: It is known that nano-and microparticles have been very popular in recent years since their advantages. However, due to the very small size of such materials, they have very high tendency to agglomeration particularly for nanoparticles. Therefore, it is critical that they are properly distributed in the system to which they are added. This paper investigated the effects of dry particle coating with nano-and microparticles to solve the agglomeration problem. For a clear evaluation, paste samples were preferred to detemine the compressive strength. Nano-SiO2 and nano-CaCO3, micro-CaCO3 and micro-SiO2, also known as silica fume, were selected as particulate additives. It was studied by the addition of various percentages (0.3, 0.7, 1, 2, 3 and 5%) of nano-and microparticles in cementitious systems, replacing cement by weight with and without dry particle coating. Dry particle coating was made by using a high-speed paddle mixer. Portland cement and additive particles were mixed at 1500 rpm for 30 seconds in high-speed powder mixer designed for this purpose. The 3-day compressive strength of the cement-based samples to which particles were added at the specified rates was determined and the effect of the dry particle coating on the early strength was investigated. According to the results, it was observed that the production of paste with the dry particle coating technique gave higher compressive strength compared to the production of paste directly in early period. Especially with dry particle coating, compressive strength increased more than 100% in paste samples containing 0.3% nano-SiO2 compared to direct addition without coating.
  PubDate: 2021-12-16
  DOI: 10.20528/cjcrl.2021.04.002
  Issue No: Vol. 12, No. 4 (2021)
Strength properties of biopolymer treated clay/marble powder mixtures
- Authors: Zeynep Nese Kurt Albayrak, Banu Altun
  Pages: 131 - 137
  Abstract: Depending on their unique layer structures and chemical structures, soil problems such as swelling, settlement and loss of strength can be seen especially on clay soils when exposed to water. Settlement occurring on clay soils on which the structure is built, causes various damages in the building. Additionally, in the clay soil interacting with water, strength loss occurs due to the effect of the building load. Today, when soil improvement techniques are developed and diversified, clay soils can be stabilized by using different additives. A clay soil that has been improved by adding waste marble powder within the scope of this study in certain percentages (5%, 15%, 25%), biopolymer added clay / marble powder samples were obtained by interacting with locust bean gum in certain percentages (0.5%, 1%, 1.5%). There are many studies in the literature on improving clay soils using only marble powder or only biopolymer. In this study, marble powder and biopolymer were used together and thus, the feasibility of a more effective soil improvement has been investigated. The results showed that the unconfined compressive strength of the biopolymer added clay-marble powder mixtures are higher when compared with natural clay. Similarly, shear box test results showed that the unconsolidated-undrained cohesions and internal friction angles of the doped clay samples increased. It was observed that the strength values of marble powder-added clay increased after improving with biopolymer.
  PubDate: 2021-12-16
  DOI: 10.20528/cjcrl.2021.04.003
  Issue No: Vol. 12, No. 4 (2021)
Predictability of concrete damage level by non-destructive test methods
- Authors: Boğaçhan Akça, Süleyman Bahadır Keskin, Aysu Göçügenci
  Pages: 138 - 150
  Abstract: Non-destructive methods have many advantages over traditional test methods, especially since it does not damage the specimen, it can be used multiple times on the same specimen. These advantages also provide a great benefit in terms of following the property development in concrete as the same specimens are used which eliminates the variations related to the specimens. In this study, it is aimed to determine the damaged amount of concrete produced with different binders by electrical bulk resistivity, resonance frequency, and ultrasonic pulse velocity methods. Firstly, concretes containing different binders were produced, and along with the mechanical properties, ultrasonic wave velocity, resonance frequency, and electrical resistivity values of the produced concrete were determined at the 7, 28, and 90 days. Besides, the specimens were subjected to gradually increase compressive loads and non-destructive methods were used to estimate the extent of damage on specimens. It was attempted to establish a relationship between the damage on concrete specimens and the results obtained by non-destructive methods. Consequently, the compressive strength, electrical resistivity, ultrasonic pulse velocity and resonance frequency values of all specimens increased with the advancing age. It was concluded that the resonant frequency method is more successful than other methods in estimating the amount of damage in concrete.
  PubDate: 2021-12-16
  DOI: 10.20528/cjcrl.2021.04.004
  Issue No: Vol. 12, No. 4 (2021)
Cover & Contents Vol.12 No.3
- Authors: Journal Management CJCRL
  PubDate: 2021-09-15
  Issue No: Vol. 12, No. 3 (2021)
Cover & Contents Vol.12 No.2
- Authors: Journal Management CJCRL
  PubDate: 2021-06-23
  Issue No: Vol. 12, No. 3 (2021)
Mechanical properties and freeze-thaw resistances of bronze-concrete
composites
- Authors: Tuba Bahtli, Nesibe Sevde Ozbay
  Pages: 39 - 48
  Abstract: Studies in the literature show that the physical and mechanical properties of concrete could be improved by the incorporation of different kinds of industrial waste, including waste tire rubber and tire steel. Recycling of waste is important for economic gain and to curb environmental problems. In this study, finely ground CuAl10Ni bronze is used to improve the physical and mechanical properties, and freeze-thaw resistances of C30 concrete. The density, cold crushing strength, 3-point bending strength, elastic modulus, toughness, and freeze-thaw resistances of concrete are determined. In addition, the Schmidt Rebound Hammer (SRH) and the ultrasonic pulse velocity (UPV) tests, which are non-destructive test methods, are applied. SEM/EDX analyses are also carried out. It is noted that a more compacted structure of concrete is achieved with the addition of bronze sawdust. Then higher density and strength values are obtained for concretes that are produced by bronze addition. In addition, concretes including bronze sawdust generally show higher toughness due to high plastic energy capacities than pure concrete.
  PubDate: 2021-06-23
  DOI: 10.20528/cjcrl.2021.02.001
  Issue No: Vol. 12, No. 3 (2021)
Ductility of simply supported rubberized concrete beams
- Authors: Ahmed Youssef Kamal
  Pages: 49 - 57
  Abstract: Dispose of waste rubberized tires become a dangerous problem around the world, represented a big serious risk to the sur-rounded environment. Many studies show that over 1000 million tires reach their expired date yearly and this figure is anticipated to be 5000 million tires by reaching 2030. A minor part of them is employed as recycled materials and the residual amount is stockpiled or buried. This paper aimed to successfully utilize the vast amounts of tire rubber waste existing currently in landfills. This paper represents a practical investigation of the ductility performance of the reinforced rubberized concrete beams. Thirteen reinforced concrete beams simply supported, with waste rubber tires mixtures vary from 0 to 8 percentage as aggregates replacements, were tested by mid-span load. Therefore, to examine the ductility performance of reinforced rubberized concrete beams, three sets of samples were made. In the first group, coarse aggregates in the concrete mix were replaced by different percentages of the waste rubber partials, while for the second group, crumb rubber was replaced for the fine aggregates, and for the third one, a mix of waste and crumbed rubber were replaced for both types of aggregates. Experimental results of rubberized specimens were also compared with that of the reference beam (without rubber replacement), the comparison results declare that concrete contains rubber particles is less ductile than conventional concrete.
  PubDate: 2021-06-23
  DOI: 10.20528/cjcrl.2021.02.002
  Issue No: Vol. 12, No. 3 (2021)
Properties of Portland cement concrete cast with magnetized water: a
review
- Authors: Mariam Farouk Ghazy, Metwally Abd Allah Abd Elaty, Omar Hussein Khalifa
  Pages: 58 - 71
  Abstract: The water utilized in concrete manufacture plays an important role within the concrete mix, beginning from controlling the process of hydration of cement, besides appropriate curing to achieve the required strength, not to mention controlling the workability and durability of the concrete structure. The utmost significant challenge for concrete technology is to improve the properties of concrete. Nowadays, the engineering field needs to produce structures in harmony with the concept of sustainable development through the utilization of high-performance materials with an eco-friendly impact that is produced at a low-cost. The magnetic water (MW) provides one of the utmost towards this objective. The cost of magnetizing water is low because of the simple instruments used and the cost can be adapted to the scale of the work. In the last two decades, a new technology, so-called MW technology, has been extended to use in concrete manufacturing. Therefore, currently, the researchers are interested in the use of MW in the manufacture of cementitious materials helping to rationalize the cement usage and reducing reliance on chemical additives that have a negative environmental impact. Consequently, this paper presents the effect of the magnetization process in the structure of water molecules, the main properties of water. Additionally, the effect of using MW on the fresh and mechanical properties, as well as the durability characteristics and performance of cementitious materials have been reviewed. Moreover, the factors that affect the magnetization process of water, which highlighted discuss in this study. The results revealed that using MW significantly enhances the flowability and the characteristic strengths of cementitious materials as well as the durability properties.
  PubDate: 2021-06-23
  DOI: 10.20528/cjcrl.2021.02.003
  Issue No: Vol. 12, No. 3 (2021)
Predicting and comparing the fire performance of a small-scale composite
structure
- Authors: Burak Kaan Cirpici
  Pages: 72 - 87
  Abstract: The purpose of this paper is to investigate a strategy for the fire testing of reduced scale structural models which will help engineers design safer structures and reduce the loss from fires. The concept of this work is how composite frame floor arrangements, beam-column connections might be modelled at a small scale suitable for fire testing. Testing full-scale is expensive, besides the testing of scaled model produces reasonable results which help us to understand the failure mechanism and all significant thermo-structural responses involved in a fire. Thermal effects within a structural element generate fire curve, thermal input and structural displacement output, in other words cause and impact. Dimensional analysis, which is a condition for dynamic similarity between prototype and model, can be achieved when all the dimensionless groups are set equal for both model and prototype. On the other hand, scaling rules are used to decide how much insulating material will be used on a structure. 5-storey composite building with composite floors and steel columns has been modelled at small scale with 1/5. The obtained results from various parametric investigations show that the reduced scale model fire test method would be a feasible way to investigate the fire performance of composite structures.
  PubDate: 2021-09-15
  DOI: 10.20528/cjcrl.2021.03.001
  Issue No: Vol. 12, No. 3 (2021)
Diffusion study of chloride and binding of water in concrete pore by
molecular dynamics simulation using LAMMPS
- Authors: Md. Shafiqul Islam, Sayem Ahmeed, Sumon Kumar Ghosh
  Pages: 88 - 95
  Abstract: As for the communication between concrete and the particles, the surface shows Cl− shock and Na adsorption. With expanded particle focus, the solid adsorption capacity for Cl− is upgraded as a result of a detailed overview of the dynamic molecular simulation studies examining the chloride diffusion coefficient. Different characteristics of the diffusion process, including molecular models, system-size effects, temperature, and pressure conditions, and the type of protection, are discussed. This paper focus on Molecular Dynamic Simulation to determine the diffusion coefficient of chloride ion and water molecules in concrete. The diffusion coefficient for NaCl salt obtained 6.60178x10-10m2/s and the diffusion coefficient for CaCl2 salt obtained 7.29305x10-10m2/s. So, the average chloride diffusion coefficient 6.9475x10-10m2/s. Diffusion coefficient obtained from graph 5.562x10-10m2/s. Diffusion coefficients for water molecules for NaCl solution are 6.125x10-10m2/s, 6.85x10-10m2/s, 1.044x10-10m2/s, 8.525x10-10m2/s, 6.25x10-10m2/s. diffusion coefficient of water molecules in CaCl2 solution are 4.5x10-10m2/s, 6.725x10-10m2/s, 1.254x10-10m2/s, 7.725x10-10m2/s, 1.3x10-10m2/s. Average value obtained for water molecule diffusion are 4.545x10-10m2/s, 7.4062x10-10m2/s and 1.149x10-10m2/s. This diffusion of chloride effects the binding of water in concrete pore.
  PubDate: 2021-09-15
  DOI: 10.20528/cjcrl.2021.03.002
  Issue No: Vol. 12, No. 3 (2021)
Mechanical strength variation of zeolite-fly ash geopolymer mortars with
different activator concentrations
- Authors: Roble İbrahim Liban, Ülkü Sultan Keskin, Oğuzhan Öztürk
  Pages: 96 - 103
  Abstract: Zeolite is of a significance for geopolymers as it is a natural precursor and does not require additional heat treatment for activation. However, aluminosilicates sourced from natural sources require additional handling for the best use of exploitation. In this study, geopolymers were synthesized by binary use of zeolite and fly ash as main binding material and sodium silicate and sodium hydroxide as alkaline activator. The influence of alkaline activator ratios and sodium hydroxide concentrations on the compressive strength and flexural strength of the zeolite-fly ash based geopolymers were studied. In this research, zeolite-fly ash based geopolymer mortars were produced by using 50% of natural zeolite (clinoptilolite) and 50% of C-type fly ash. Four different activator ratios (Na2SiO3/NaOH: 1, 1.5, 2 and 2.5) and two sodium hydroxide molarities (10M and 12M) was utilized to activate zeolite and fly ash in order to determine the effect of these parameters on the mechanical strengths of the produced geopolymer mortars. The results indicated that as the alkaline activator ratio and NH molarity were increased the compressive strength of the zeolite-fly ash based geopolymers also increased. The maximum compressive and flexural strength values obtained after 28 days of curing were 20.1 MPa and 5.3 MPa respectively and corresponds when used activator ratio of 2.5 and sodium hydroxide concentration of 12 molarity. The obtained results indicated that both the alkaline activator ratio and sodium hydroxide concentration affected the compressive and flexural strengths of zeolite-fly ash based geopolymer mortar specimens.
  PubDate: 2021-09-15
  DOI: 10.20528/cjcrl.2021.03.003
  Issue No: Vol. 12, No. 3 (2021)
Effect of retardant admixtures type and their using method on the behavior
of concrete
- Authors: Tamer Ibrahim Ahmed, Mohamed Roshdy Afify
  Pages: 104 - 113
  Abstract: Construction sites may be exposed to crisis conditions during the casting process, resulting in delays of several hours and causing destruction of ready-mix concrete. This study suggests an experimental analysis of the possibility of using a specific additional dose of retardant admixtures, which may be used to ready-mix concrete before the initial setting of the concrete occurs. The effect of this additional dose on concrete characteristics in terms of workability, setting time, and compressive strength is also being studied. To conduct this investigation, three types of retardant admixtures from three branded companies were used. In addition, a penetration resistance experiment was conducted on the concrete to determine its setting time. The setting time of concrete was measured at different period intervals depending on when the additional dose of the retardant admixtures was added from the start of the concrete mixing. The results showed that concrete maintained proper workability for a period of more than 5 hours after using the additional dose of retarding admixtures. The additional dose of retarding admixtures not only delayed the concrete setting but also improved the compressive strength of the concrete. This implies that the use of an additional dose of retardant admixtures specifically tailored for ready-mix concrete is an effective option to avoid the return of ready-mixed fresh concrete.
  PubDate: 2021-09-15
  DOI: 10.20528/cjcrl.2021.03.004
  Issue No: Vol. 12, No. 3 (2021)
Cover & Contents Vol.12 No.1
- Authors: Journal Management CJCRL
  PubDate: 2021-03-12
  Issue No: Vol. 12, No. 1 (2021)
Effect of high temperature on SCC containing fly ash
- Authors: Mehmet Canbaz, Erman Acay
  Pages: 1 - 11
  Abstract: The effect of high temperature on self-compacting concrete, which contains different amounts of fly ash, has been investigated. By considering the effect of concrete age and increased temperatures, the optimum fly ash-cement ratio for the optimum concrete strength is determined using experimental studies. Self-compacting concrete specimens are produced, with fly ash/cement ratios of 0%, 20% and 40%. Specimens were cured for 28, 56 and 90 days. After curing was completed, the specimens were subjected to temperatures of 20°C, 100°C, 400°C, 700°C and 900°C for three hours. After the cooling process, tests were performed to determine the unit weight, ultrasonic pulse velocity and compressive strength of the specimens. According to the experiment results, an increase in fly ash ratio causes a decrease in the compressive strength of self-compacting concrete. However, it positively contributes to self-compaction and strength loss at high temperatures. The utilization of fly ash in concrete significantly contributes to the environment and the economy. For this reason, the addition of 20% fly ash to concrete is considered to be effective.
  PubDate: 2021-03-12
  DOI: 10.20528/cjcrl.2021.01.001
  Issue No: Vol. 12, No. 1 (2021)
Application of an artificial neural network for predicting compressive and
flexural strength of basalt fiber added lightweight concrete
- Authors: Gokhan Calis, Sadık Alper Yıldızel, Ülkü Sultan Keskin
  Pages: 12 - 19
  Abstract: Concrete is known as one of the fundamental materials in construction with its high amount of use. Lightweight concrete (LWC) can be a good alternative in reducing the environmental effect of concrete by decreasing the self-weight and dimensions of the structure. In order to reduce self-weight of concrete artificial aggregates, some of which are produced from waste materials, are utilized, and it also contributes to develop a sustainable material Artificial neural networks have been the focus of many scholars for long time with the purpose of analyzing and predicting the lightweight concrete compressive and flexural strengths. The artificial neural network is more powerful method in terms of providing explanation and prediction in engineering studies. It is proved that the error rate of ANN is smaller than regression method. Furthermore, ANN has superior performance over nonlinear regression model. In this paper, an ANN based system is proposed in order to provide a better understanding of basalt fiber reinforced lightweight concrete. In the regression analysis predicted vs. experimental flexural strength, R-sqr is determined to be 86%. The most important strength contributing factors were analyzed within the scope of this study.
  PubDate: 2021-03-12
  DOI: 10.20528/cjcrl.2021.01.002
  Issue No: Vol. 12, No. 1 (2021)
Study on concrete proportioning methods: a qualitative and economical
perspective
- Authors: Shoib Bashir Wani, Tahir Hussain Muntazari, Nusrat Rafique
  Pages: 20 - 29
  Abstract: The various approaches, established for concrete mix design, are not universal because design mixes are explicit to local climate, available materials, and type of exposure. The new-generation mix design method should be developed based on the performance criteria. The concrete strength obtained from the designed concrete mix and optimum cement content should not be considered as the only parameter for the suitability of the concrete mix. This study was carried to compare the proportioning of concrete mixes obtained by following procedures of Indian Standard (IS), American Concrete Institute (ACI) and British Standard (BS) of concrete mix design without the use of admixtures to validate for use in a moderate climate like Kashmir, India. The concrete mixes have been prepared with the necessary 28 days resistance in compression as “15 MPa, 20 MPa, 25 MPa, 30 MPa and 35 MPa”. The assessment of water-cement (w/c) ratio; cement, water, fine aggregate (FA) and coarse aggregate (CA) proportion was carried. The w/c ratio among all formulated mixes is significantly high in the BS method and low for IS method. The BS method uses less quantity and IS method uses the maximum quantity of cement. In addition, the ratio of total aggregate content (TAC) and the aggregate-cement ratio is higher in BS design method as compared to IS and ACI design methods. The aggregate content in ACI mix design appears to be consistent and it added to the relative high compressive strength. The specimens cast following BS guidelines failed to attain the target mean strength (TMS) due to a higher volume of aggregate content, high w/c proportion, less quantity of cement in the mix. The specimens cast by ACI and IS mix design upon compression testing showed higher results than the calculated TMS. The cost analysis per cubic meter of concrete revealed that IS and ACI mix proportioning are expensive than BS method. The IS procedure results in dense concrete followed by ACI procedure. It is expected that with a comprehensive investigation on selected design parameters concentrating more on local challenges, the present study will floor the way for the development and adoption of performance-based design mix selection for moderate climate.
  PubDate: 2021-03-12
  DOI: 10.20528/cjcrl.2021.01.003
  Issue No: Vol. 12, No. 1 (2021)
Effect of different fiber types on the mechanical properties of normal and
high strength concrete at elevated temperatures
- Authors: Mohamed Amin, Khaled Abu el-hassan
  Pages: 30 - 38
  Abstract: The effects of the types of fibers on mechanical properties of normal and high strength concrete under high temperature, up to 700 °C, was investigated. Three different- type fiber; "Steel Fiber (SF), Glass Fiber (GF) and Polypropylene Fiber (PPF)" are added into the concretes in five different ratios (0, 0.50, 1.00, 1.50 and 2.0%)of the volume under the following temperatures; 22, 100, 400 and 700°C. The results indicate that all the different types of fibers researched contribute to both the compressive and flexural strengths of concrete under high temperature, however, it is also found that this contribution decreases with an increase in temperature. The flexural strengths and compressive strengths for NSC and HSC mixes at 28 days under high temperature decreases as the temperature increases especially up to 400°C. Also, the best compressive and flexural strengths performance under high temperature was also those of SF. The compressive strength of the concrete incorporating SF was reduced under high temperature only, while the mixes containing PPF and GF were reduced under high temperature or with fiber addition. The optimum fiber addition ratios of the mixes containing PPF and GF are between 0.5-1.0 percent by volume. And for SF, it is 1.5% by the volume.
  PubDate: 2021-03-12
  DOI: 10.20528/cjcrl.2021.01.004
  Issue No: Vol. 12, No. 1 (2021)