Search results for: high strength concrete
6679 Effect of One-Handed Pushing and Puling Strength at Different Handle Heights in Vertical Direction
Authors: Tarik H. Badi, Amer A. Boushaala
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The purpose of this study was to measure the maximal isometric strength and to investigate the effects of different handleheights and elbow angles with respect to Mid. sagittal plane on the pushing and pulling strength in vertical direction. Eight male subjects performed a series of static strength measurement for each subject. The highest isometric strength was found in pulling at shoulder height (S.H.) (Mean = 60.29 lb., SD = 16.78 lb.) and the lowest isometric strength was found also in pulling at elbow height (E.H.) (Mean = 33.06 lb., SD = 6.56 lb.). Although the isometric strengths were higher at S.H than at E.H. for both activities, the maximal isometric strengths were compared statistically. ANOVA was performed. The results of the experiment revealed that there was a significant different between handle heights. However, there were no significant different between angles and activities, also no correlation between grip strength and activities.Keywords: Pushing and pulling, one arm, vertical direction, isometric strength.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 30646678 Influential Effect of Self-Healing Treatment on Water Absorption and Electrical Resistance of Normal and Light Weight Aggregate Concretes
Authors: B. Tayebani, N. Hosseinibalam, D. Mostofinejad
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Interest in using bacteria in cement materials due to its positive influences has been increased. Cement materials such as mortar and concrete basically suffer from higher porosity and water absorption compared to other building materials such as steel materials. Because of the negative side-effects of certain chemical techniques, biological methods have been proposed as a desired and environmentally friendly strategy for reducing concrete porosity and diminishing water absorption. This paper presents the results of an experimental investigation carried out to evaluate the influence of Sporosarcina pasteurii bacteria on the behaviour of two types of concretes (light weight aggregate concrete and normal weight concrete). The resistance of specimens to water penetration by testing water absorption and evaluating the electrical resistance of those concretes was examined and compared. As a conclusion, 20% increase in electrical resistance and 10% reduction in water absorption of lightweight aggregate concrete (LWAC) and for normal concrete the results show 7% decrease in water absorption and almost 10% increase in electrical resistance.
Keywords: Bacteria, biological method, normal weight concrete, lightweight aggregate concrete, water absorption, electrical resistance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 9846677 Freeze-Thaw Resistance of Concretes with BFSA
Authors: Alena Sicakova
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Air-cooled Blast Furnace Slag Aggregate (BFSA) is usually referred to as a material providing for unique properties of concrete. On the other hand, negative influences are also presented in many aspects. The freeze-thaw resistance of concrete is dependent on many factors, including regional specifics and when a concrete mix is specified it is still difficult to tell its exact freeze-thaw resistance due to the different components affecting it. An important consideration in working with BFSA is the granularity and whether slag is sorted or not. The experimental part of the article represents a comparative testing of concrete using both the sorted and unsorted BFSA through the freeze-thaw resistance as an indicator of durability. Unsorted BFSA is able to be successfully used for concretes as they are specified for exposure class XF4 with providing that the type of cement is precisely selected.
Keywords: Blast furnace slag aggregate, concrete, freeze-thaw resistance.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 23216676 Tensile Properties of Aluminum Silicon Nickel Iron Vanadium High Entropy Alloys
Authors: Sefiu A. Bello, Nasirudeen K. Raji, Jeleel A. Adebisi, Sadiq A. Raji
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Pure metals are not used in most cases for structural applications because of their limited properties. Presently, high entropy alloys (HEAs) are emerging by mixing comparative proportions of metals with the aim of maximizing the entropy leading to enhancement in structural and mechanical properties. Aluminum Silicon Nickel Iron Vanadium (AlSiNiFeV) alloy was developed using stir cast technique and analysed. Results obtained show that the alloy grade G0 contains 44 percentage by weight (wt%) Al, 32 wt% Si, 9 wt% Ni, 4 wt% Fe, 3 wt% V and 8 wt% for minor elements with tensile strength and elongation of 106 Nmm-2 and 2.68%, respectively. X-ray diffraction confirmed intermetallic compounds having hexagonal closed packed (HCP), orthorhombic and cubic structures in cubic dendritic matrix. This affirmed transformation from the cubic structures of elemental constituents of the HEAs to the precipitated structures of the intermetallic compounds. A maximum tensile strength of 188 Nmm-2 with 4% elongation was noticed at 10wt% of silica addition to the G0. An increase in tensile strength with an increment in silica content could be attributed to different phases and crystal geometries characterizing each HEA.
Keywords: High entropy alloys, phases, model, tensile strength.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 7306675 Impact of Carbonation on Lime-Treated High Plasticity Index Clayey Soils
Authors: Saurav Bhattacharjee, Syam Nair
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Lime stabilization is a sustainable and economically viable option to address strength deficiencies of subgrade soils. However, exposure of stabilized layers to environmental elements can lead to a reduction in post-stabilization strength gain expected in these layers. The current study investigates the impact of carbonation on the strength properties of lime-treated soils. Manufactured soils prepared using varying proportions of bentonite silica mixtures were used in the study. Lime-treated mixtures were exposed to different atmospheric conditions created by varying the concentrations of CO₂ in the testing chamber. The impact of CO₂ diffusion was identified based on changes in carbonate content and unconfined compressive strength (UCS) properties. Changes in soil morphology were also investigated as part of the study. The rate of carbonation was observed to vary polynomially (2nd order) with exposure time. The strength properties of the mixes were observed to decrease with exposure time.
Keywords: Manufactured soil, carbonation, morphology, unconfined compressive strength.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 836674 Finite Element Approach to Evaluate Time Dependent Shear Behavior of Connections in Hybrid Steel-PC Girder under Sustained Loading
Authors: Mohammad Najmol Haque, Takeshi Maki, Jun Sasaki
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Headed stud shear connections are widely used in the junction or embedded zone of hybrid girder to achieve whole composite action with continuity that can sustain steel-concrete interfacial tensile and shear forces. In Japan, Japan Road Association (JRA) specifications are used for hybrid girder design that utilizes very low level of stud capacity than those of American Institute of Steel Construction (AISC) specifications, Japan Society of Civil Engineers (JSCE) specifications and EURO code. As low design shear strength is considered in design of connections, the time dependent shear behavior due to sustained external loading is not considered, even not fully studied. In this study, a finite element approach was used to evaluate the time dependent shear behavior for headed studs used as connections at the junction. This study clarified, how the sustained loading distinctively impacted on changing the interfacial shear of connections with time which was sensitive to lodging history, positions of flanges, neighboring studs, position of prestress bar and reinforcing bar, concrete strength, etc. and also identified a shear influence area. Stud strength was also confirmed through pushout tests. The outcome obtained from the study may provide an important basis and reference data in designing connections of hybrid girders with enhanced stud capacity with due consideration of their long-term shear behavior.
Keywords: Finite element approach, hybrid girder, headed stud shear connections, sustained loading, time dependent shear behavior.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 6146673 A Review on Application of Waste Tire in Concrete
Authors: M. A. Yazdi, J. Yang, L. Yihui, H. Su
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The application of recycle waste tires into civil engineering practices, namely asphalt paving mixtures and cementbased materials has been gaining ground across the world. This review summarizes and compares the recent achievements in the area of plain rubberized concrete (PRC), in details. Different treatment methods have been discussed to improve the performance of rubberized Portland cement concrete. The review also includes the effects of size and amount of tire rubbers on mechanical and durability properties of PRC. The microstructure behaviour of the rubberized concrete was detailed.Keywords: Waste rubber aggregates, Microstructure, Treatment methods, Size and content effects.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 46486672 Overtopping Protection Systems for Overflow Earth Dams
Authors: Omid Pourabdollah, Mohsen Misaghian
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Overtopping is known as one the most important reasons for the failure of earth dams. In some cases, it has resulted in heavy damages and losses. Therefore, enhancing the safety of earth dams against overtopping has received much attention in the past four decades. In this paper, at first, the overtopping phenomena and its destructive consequences will be introduced. Then, overtopping failure mechanism of embankments will be described. Finally, different types of protection systems for stabilization of earth dams against overtopping will be presented. These include timber cribs, riprap and gabions, reinforced earth, roller compacted concrete, and the precast concrete blocks.
Keywords: Embankment dam, overtopping, roller compacted concrete, wedge concrete block.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 8526671 Six Sigma Solutions and its Benefit-Cost Ratio for Quality Improvement
Authors: S. Homrossukon, A. Anurathapunt
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This is an application research presenting the improvement of production quality using the six sigma solutions and the analyses of benefit-cost ratio. The case of interest is the production of tile-concrete. Such production has faced with the problem of high nonconforming products from an inappropriate surface coating and had low process capability based on the strength property of tile. Surface coating and tile strength are the most critical to quality of this product. The improvements followed five stages of six sigma solutions. After the improvement, the production yield was improved to 80% as target required and the defective products from coating process was remarkably reduced from 29.40% to 4.09%. The process capability based on the strength quality was increased from 0.87 to 1.08 as customer oriented. The improvement was able to save the materials loss for 3.24 millions baht or 0.11 million dollars. The benefits from the improvement were analyzed from (1) the reduction of the numbers of non conforming tile using its factory price for surface coating improvement and (2) the materials saved from the increment of process capability. The benefit-cost ratio of overall improvement was high as 7.03. It was non valuable investment in define, measure, analyses and the initial of improve stages after that it kept increasing. This was due to there were no benefits in define, measure, and analyze stages of six sigma since these three stages mainly determine the cause of problem and its effects rather than improve the process. The benefit-cost ratio starts existing in the improve stage and go on. Within each stage, the individual benefitcost ratio was much higher than the accumulative one as there was an accumulation of cost since the first stage of six sigma. The consideration of the benefit-cost ratio during the improvement project helps make decisions for cost saving of similar activities during the improvement and for new project. In conclusion, the determination of benefit-cost ratio behavior through out six sigma implementation period provides the useful data for managing quality improvement for the optimal effectiveness. This is the additional outcome from the regular proceeding of six sigma.Keywords: Six Sigma Solutions, Process Improvement, QualityManagement, Benefit Cost Ratio
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21196670 Reliability Analysis of P-I Diagram Formula for RC Column Subjected to Blast Load
Authors: Masoud Abedini, Azrul A. Mutalib, Shahrizan Baharom, Hong Hao
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This study was conducted published to investigate there liability of the equation pressure-impulse (PI) reinforced concrete column inprevious studies. Equation involves three different levels of damage criteria known as D =0. 2, D =0. 5 and D =0. 8.The damage criteria known as a minor when 0-0.2, 0.2-0.5is known as moderate damage, high damage known as 0.5-0.8, and 0.8-1 of the structure is considered a failure. In this study, two types of reliability analyzes conducted. First, using pressure-impulse equation with different parameters. The parameters involved are the concrete strength, depth, width, and height column, the ratio of longitudinal reinforcement and transverse reinforcement ratio. In the first analysis of the reliability of this new equation is derived to improve the previous equations. The second reliability analysis involves three types of columns used to derive the PI curve diagram using the derived equation to compare with the equation derived from other researchers and graph minimum standoff versus weapon yield Federal Emergency Management Agency (FEMA). The results showed that the derived equation is more accurate with FEMA standards than previous researchers.
Keywords: Blast load, RC column, P-I curve, Analytical formulae, Standard FEMA.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 28936669 Analysis of the Influence of Reshoring on the Structural Behavior of Reinforced Concrete Beams
Authors: Keith Danila Aquino Neves, Júlia Borges dos Santos
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There is little published research about the influence of execution methods on structural behavior. Structural analysis is typically based on a constructed building, considering the actions of all forces under which it was designed. However, during construction, execution loads do not match those designed, and in some cases the loads begin to act when the concrete has not yet reached its maximum strength. Changes to structural element support conditions may occur, resulting in unforeseen alterations to the structure’s behavior. Shoring is an example of a construction process that, if executed improperly, will directly influence the structural performance, and may result in unpredicted cracks and displacements. The NBR 14931/2004 standard, which guides the execution of reinforced concrete structures, mentions that shoring must be executed in a way that avoids unpredicted loads and that it may be removed after previous analysis of the structure’s behavior by the professional responsible for the structure’s design. Differences in structural behavior are reduced for small spans. It is important to qualify and quantify how the incorrect placement of shores can compromise a structure’s safety. The results of this research allowed a more precise acknowledgment of the relationship between spans and loads, for which the influence of execution processes can be considerable, and reinforced that civil engineering practice must be performed with the presence of a qualified professional, respecting existing standards’ guidelines.
Keywords: Structural analysis, structural behavior, reshoring, static scheme, reinforced concrete.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 7596668 Characterization of Cement Mortar Based on Fine Quartz
Authors: K. Arroudj, M. Lanez, M. N. Oudjit
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The introduction of siliceous mineral additions in cement production allows, in addition to the ecological and economic gain, improvement of concrete performance. This improvement is mainly due to the fixing of Portlandite, released during the hydration of cement, by fine siliceous, forming denser calcium silicate hydrates and therefore a more compact cementitious matrix. This research is part of the valuation of the Dune Sand (DS) in the cement industry in Algeria. The high silica content of DS motivated us to study its effect, at ground state, on the properties of mortars in fresh and hardened state. For this purpose, cement pastes and mortars based on ground dune sand (fine quartz) has been analyzed with a replacement to cement of 15%, 20% and 25%. This substitution has reduced the amount of heat of hydration and avoids any risk of initial cracking. In addition, the grinding of the dune sand provides amorphous thin populations adsorbed at the surface of the crystal particles of quartz. Which gives to ground quartz pozzolanic character. This character results an improvement of mechanical strength of mortar (66 MPa in the presence of 25% of ground quartz).
Keywords: Mineralogical structure, Pozzolanic reactivity, quartz, mechanical strength.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 10026667 Experimental Analysis of Composite Timber-Concrete Beam with CFRP Reinforcement
Authors: O. Vlcek
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The paper deals with current issues in research of advanced methods to increase reliability of traditional timber structural elements. It analyses the issue of strengthening of bent timber beams, such as ceiling beams in old (historical) buildings with additional concrete slab in combination with externally bonded fibre - reinforced polymer. The paper describes experimental testing of composite timber-concrete beam with FRP reinforcement and compares results with FEM analysis.
Keywords: Timber-concrete composite, strengthening, fibre-reinforced polymer, experimental analysis.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 21066666 Shear Strengthening of RC T Beam using CFRP Laminate: A Review
Authors: M.B.S. Alferjani, A.A. Abdul Samad, N. Mohamad, M. Hilton, N. Ali
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This paper presents the Literature Review of carbon fiber reinforced polymer (CFRP) strips to reinforced concrete (RC) as a strengthening solution for T-beams. Although a great deal of research has been carried out on Rectangular beams strengthened with Fibre-Reinforced Polymer composites (FRP), Fiber reinforced polymer (FRP) composites have been increasingly studied for their application in the flexural or shear strengthening of reinforced concrete (RC) members. A detailed discussion of the shearstrengthening repair with FRP is undertaken. This paper will be limited to research of CFRP material externally bonded to the tensile face of concrete beams. In particular, research studying the effect of externally applied CFRP materials on the shear performance of reinforced concrete beams will be reported.
Keywords: CFRP, Concrete, Flexural, FRP, Shear, Strengthening.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 28466665 Developing Marketing Strategy in Nonmetallic Mineral Industry at the Business Level
Authors: Nader Gharibnavaz, Naser Gharibnavaz
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This study extends research on the relationship between marketing strategy and market segmentation by investigating on market segments in the cement industry. Competitive strength and rivals distance from the factory were used as business environment. A three segment (positive, neutral or indifferent and zero zones) were identified as strategic segments. For each segment a marketing strategy (aggressive, defensive and decline) were developed. This study employed data from cement industry to fulfill two objectives, the first is to give a framework to the segmentation of cement industry and the second is developing marketing strategy with varying competitive strength. Fifty six questionnaires containing close-and open-ended questions were collected and analyzed. Results supported the theory that segments tend to be more aggressive than defensive when competitive strength increases. It is concluded that high strength segments follow total market coverage, concentric diversification and frontal attack to their competitors. With decreased competitive strength, Business tends to follow multi-market strategy, product modification/improvement and flank attack to direct competitors for this kind of segments. Segments with weak competitive strength followed focus strategy and decline strategy.Keywords: Marketing strategy, Competitive strength, Market Segmentation
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17496664 Site Inspection and Evaluation Behavior of Qing Shang Concrete Bridge
Authors: Haleem K. Hussain, Liu Gui Wei, Zhang Lian Zhen, Yongxue Li
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It is necessary to evaluate the bridges conditions and strengthen bridges or parts of them. The reinforcement necessary due to some reasons can be summarized as: First, a changing in use of bridge could produce internal forces in a part of structural which exceed the existing cross-sectional capacity. Second, bridges may also need reinforcement because damage due to external factors which reduced the cross-sectional resistance to external loads. One of other factors could listed here its misdesign in some details, like safety of bridge or part of its.This article identify the design demands of Qing Shan bridge located in is in Heilongjiang Province He gang - Nen Jiang Road 303 provincial highway, Wudalianchi area, China, is an important bridge in the urban areas. The investigation program was include the observation and evaluate the damage in T- section concrete beams , prestressed concrete box girder bridges section in additional evaluate the whole state of bridge includes the pier , abutments , bridge decks, wings , bearing and capping beam, joints, ........etc. The test results show that the bridges in general structural condition are good. T beam span No 10 were observed, crack extended upward along the ribbed T beam, and continue to the T beam flange. Crack width varying between 0.1mm to 0.4mm, the maximum about 0.4mm. The bridge needs to be improved flexural bending strength especially at for T beam section.Keywords: Field investigation, prestressed concrete box girder, maintenance, Qing Shan Bridge
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18606663 Seismic Performance of Reinforced Concrete Frames Infilled by Masonry Walls with Different Heights
Authors: Ji–Wook Mauk, Yu–Suk Kim, Hyung–Joon Kim
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This study carried out comparative seismic performance of reinforced concrete frames infilled by masonry walls with different heights. Partial and fully infilled reinforced concrete frames were modeled for the research objectives and the analysis model for a bare reinforced concrete frame was also established for comparison. Non–linear static analyses for the studied frames were performed to investigate their structural behavior under extreme seismic loads and to find out their collapse mechanism. It was observed from analysis results that the strengths of the partial infilled reinforced concrete frames are increased and their ductilities are reduced, as infilled masonry walls are higher. Especially, reinforced concrete frames with higher partial infilled masonry walls would experience shear failures. Non–linear dynamic analyses using 10 earthquake records show that the bare and fully infilled reinforced concrete frame present stable collapse mechanism while the reinforced concrete frames with partially infilled masonry walls collapse in more brittle manner due to short-column effects.
Keywords: Fully infilled RC frame, partially infilled RC frame, masonry wall, short–column effects.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 25816662 Forming of Nanodimentional Structure Parts in Carbon Steels
Authors: A. Korchunov, M. Chukin, N. Koptseva, M. Polyakova, A. Gulin
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A way of achieving nanodimentional structural elements in high carbon steel by special kind of heat treatment and cold plastic deformation is being explored. This leads to increasing interlamellar spacing of ferrite-carbide mixture. Decreasing the interlamellar spacing with cooling temperature increasing is determined. Experiments confirm such interlamellar spacing with which high carbon steel demonstrates the highest treatment and hardening capability. Total deformation degree effect on interlamellar spacing value in a ferrite-carbide mixture is obtained. Mechanical experiments results show that high carbon steel after heat treatment and repetitive cold plastic deformation possesses high tensile strength and yield strength keeping good percentage elongation.
Keywords: High-carbon steel, nanodimensional structural element, interlamellar spacing.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 13286661 Cement Mortar Lining as a Potential Source of Water Contamination
Authors: M. Zielina, W. Dabrowski, E. Radziszewska-Zielina
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Several different cements have been tested to evaluate their potential to leach calcium, chromium and aluminum ions in soft water environment. The research allows comparing some different cements in order to the potential risk of water contamination. This can be done only in the same environment. To reach the results in reasonable short time intervals and to make heavy metals measurements with high accuracy, demineralized water was used. In this case the conditions of experiments are far away from the water supply practice, but short time experiments and measurably high concentrations of elements in the water solution are an important advantage. Moreover leaching mechanisms can be recognized, our experiments reported here refer to this kind of cements evaluation.
Keywords: Concrete corrosion, hydrogen sulfide, odors, reinforced concrete sewers, sewerage.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 33256660 The Effect of Screw Parameters on Pullout Strength of Screw Fixation in Cervical Spine
Authors: S. Ritddech, P. Aroonjarattham, K. Aroonjarattham
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The pullout strength had an effect on the stability of plate screw fixation when inserted in the cervical spine. Nine different titanium alloy bone screws were used to test the pullout strength through finite element analysis. The result showed that the Moss Miami I can bear the highest pullout force at 1,075 N, which causes the maximum von Mises stress at 858.87 MPa, a value over the yield strength of titanium. The bone screw should have large outer diameter, core diameter and proximal root radius to increase the pullout strength.
Keywords: Pullout strength, Screw parameter, Cervical spine, Finite element analysis.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 31466659 Seismic Fragility for Sliding Failure of Weir Structure Considering the Process of Concrete Aging
Authors: HoYoung Son, Ki Young Kim, Woo Young Jung
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This study investigated the change of weir structure performances when durability of concrete, which is the main material of weir structure, decreased due to their aging by mean of seismic fragility analysis. In the analysis, it was assumed that the elastic modulus of concrete was reduced by 10% in order to account for their aged deterioration. Additionally, the analysis of seismic fragility was based on Monte Carlo Simulation method combined with a 2D nonlinear finite element in ABAQUS platform with the consideration of deterioration of concrete. Finally, the comparison of seismic fragility of model pre- and post-deterioration was made to study the performance of weir. Results show that the probability of failure in moderate damage for deteriorated model was found to be larger than pre-deterioration model when peak ground acceleration (PGA) passed 0.4 g.Keywords: Weir, FEM, concrete, fragility, aging.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 9096658 The Influence of Zeolitic Spent Refinery Admixture on the Rheological and Technological Properties of Steel Fiber Reinforced Self-Compacting Concrete
Authors: Ž. Rudžionis, P. Grigaliūnas, D. Vaičiukynienė
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By planning this experimental work to investigate the effect of zeolitic waste on rheological and technological properties of self-compacting fiber reinforced concrete, we had an intention to draw attention to the environmental factor. Large amount of zeolitic waste, as secondary raw materials are not in use properly and large amount of it is collected without a clear view of its usage in future. The principal aim of this work is to assure, that zeolitic waste admixture takes positive effect to the self-compacting fiber reinforced concrete mixes stability, flowability and other properties by using the experimental research methods. In addition to that a research on cement and zeolitic waste mortars were implemented to clarify the effect of zeolitic waste on properties of cement paste and stone. Primary studies indicates that zeolitic waste characterizes clear pozzolanic behavior, do not deteriorate and in some cases ensure positive rheological and mechanical characteristics of self-compacting concrete mixes.
Keywords: Self compacting concrete, steel fiber reinforced concrete, zeolitic waste, rheological properties of concrete, slump flow.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 17686657 Behavior of Concrete Slab Track on Asphalt Trackbed Subjected to Thermal Load
Authors: Woo Young Jung, Seong Hyeok Lee, Jin Wook Lee, Bu Seog Ju
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Concrete track slab and asphalt trackbed are being introduced in Korea for providing good bearing capacity, durability to the track and comfortable rideness to passengers. Such a railway system has been designed by the train load so as to ensure stability. But there is lack of research and design for temperature changes which influence the behavior characteristics of concrete and asphalt. Therefore, in this study, the behavior characteristics of concrete track slab subjected to varying temperatures were analyzed through structural analysis using the finite element analysis program. The structural analysis was performed by considering the friction condition on the boundary surfaces in order to analyze the interaction between concrete slab and asphalt trackbed. As a result, the design of the railway system should be designed by considering the interaction and temperature changes between concrete track slab and asphalt trackbed.
Keywords: Con’c Track Slab, Asphalt Trackbed, Thermal Load, Friction Condition.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 34276656 Estimation of Tensile Strength for Granitic Rocks by Using Discrete Element Approach
Authors: Aliakbar Golshani, Armin Ramezanzad
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Tensile strength which is an important parameter of the rock for engineering applications is difficult to measure directly through physical experiment (i.e. uniaxial tensile test). Therefore, indirect experimental methods such as Brazilian test have been taken into consideration and some relations have been proposed in order to obtain the tensile strength for rocks indirectly. In this research, to calculate numerically the tensile strength for granitic rocks, Particle Flow Code in three-dimension (PFC3D) software were used. First, uniaxial compression tests were simulated and the tensile strength was determined for Inada granite (from a quarry in Kasama, Ibaraki, Japan). Then, by simulating Brazilian test condition for Inada granite, the tensile strength was indirectly calculated again. Results show that the tensile strength calculated numerically agrees well with the experimental results obtained from uniaxial tensile tests on Inada granite samples.
Keywords: Numerical Simulation, PFC, Tensile Strength, Brazilian Test.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 7016655 Some Design Issues in Designing of 50KW 50Krpm Permanent Magnet Synchronous Machine
Authors: Ali A. Mehna, Mohmed A. Ali, Ali S. Zayed
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A numbers of important developments have led to an increasing attractiveness for very high speed electrical machines (either motor or generator). Specifically the increasing switching speed of power electronics, high energy magnets, high strength retaining materials, better high speed bearings and improvements in design analysis are the primary drivers in a move to higher speed. The design challenges come in the mechanical design both in terms of strength and resonant modes and in the electromagnetic design particularly in respect of iron losses and ac losses in the various conducting parts including the rotor. This paper describes detailed design work which has been done on a 50,000 rpm, 50kW permanent magnet( PM) synchronous machine. It describes work on electromagnetic and rotor eddy current losses using a variety of methods including both 2D finite element analysisKeywords: High speed, PM motor, rotor and stator losses, finiteelement analysis
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 26316654 Effect of Vibration Intervention on Leg-press Exercise
Authors: Youngkuen Cho, Seonhong Hwang, Jinyoung Min, Youngho Kim, Dohyung Lim, Hansung Kim
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Many studies have emphasized the importance of resistive exercise to maintain a healthy human body, particular in prevention of weakening of physical strength. Recently, some studies advocated that an application of vibration as a supplementary means in a regular training was effective in encouraging physical strength. Aim of the current study was, therefore, to identify if an application of vibration in a resistive exercise was effective in encouraging physical strength as that in a regular training. A 3-dimensional virtual lower extremity model for a healthy male and virtual leg-press model were generated and synchronized. Dynamic leg-press exercises on a slide machine with/without extra load and on a footboard with vibration as well as on a slide machine with extra load were analyzed. The results of the current indicated that the application of the vibration on the dynamic leg-press exercise might be not greatly effective in encouraging physical strength, compared with the dynamic leg press exercise with extra load. It was, however, thought that the application of the vibration might be helpful to elderly individuals because the reduced maximum muscle strength appeared by the effect of the vibration may avoid a muscular spasm, which can be driven from a high muscle strength sometimes produced during the leg-press exercise with extra load.Keywords: Resistive exercise, leg-press exercise, muscle strength.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 18676653 Cantilever Shoring Piles with Prestressing Strands: An Experimental Approach
Authors: Hani Mekdash, Lina Jaber, Yehia Temsah
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Underground space is becoming a necessity nowadays, especially in highly congested urban areas. Retaining underground excavations using shoring systems is essential in order to protect adjoining structures from potential damage or collapse. Reinforced Concrete Piles (RCP) supported by multiple rows of tie-back anchors are commonly used type of shoring systems in deep excavations. However, executing anchors can sometimes be challenging because they might illegally trespass neighboring properties or get obstructed by infrastructure and other underground facilities. A technique is proposed in this paper, and it involves the addition of eccentric high-strength steel strands to the RCP section through ducts without providing the pile with lateral supports. The strands are then vertically stressed externally on the pile cap using a hydraulic jack, creating a compressive strengthening force in the concrete section. An experimental study about the behavior of the shoring wall by pre-stressed piles is presented during the execution of an open excavation in an urban area (Beirut city) followed by numerical analysis using finite element software. Based on the experimental results, this technique is proven to be cost-effective and provides flexible and sustainable construction of shoring works.Keywords: Excavation, inclinometer, prestressing, shoring system.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 4916652 Life Cycle Assessment of Precast Concrete Units
Authors: Ya Hong Dong, Conrad T.C. Wong, S. Thomas Ng, James M.W. Wong
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Precast concrete has been widely adopted in public housing construction of Hong Kong since the mid-1980s. While pre-casting is considered an environmental friendly solution, there is lack of study to investigate the life cycle performance of precast concrete units. This study aims to bridge the knowledge gap by providing a comprehensive life cycle assessment (LCA) study for two precast elements namely façade and bathroom. The results show that raw material is the most significant contributor of environmental impact accounting for about 90% to the total impact. Furthermore, human health is more affected by the production of precast concrete than the ecosystems.Keywords: Environment, green, LCA, LCIA, precast.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 29786651 Study the Behavior of Different Composite Short Columns (DST) with Prismatic Sections under Bending Load
Authors: V. Sadeghi Balkanlou, M. Reza Bagerzadeh Karimi, A. Hasanbakloo, B. Bagheri Azar
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In this paper, the behavior of different types of DST columns has been studied under bending load. Briefly, composite columns consist of an internal carbon steel tube and an external stainless steel wall that the between the walls are filled with concrete. Composite columns are expected to combine the advantages of all three materials and have the advantage of high flexural stiffness of CFDST columns. In this research, ABAQUS software is used for finite element analysis then the results of ultimate strength of the composite sections are illustrated.
Keywords: DST, Stainless steel, carbon steel, ABAQUS, Straigh Columns, Tapered Columns.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 35106650 Effect of Manual Compacting and Semi-Automatic Compacting on Behavior of Stabilized Earth Concrete
Authors: Sihem Chaibeddra, Fattoum Kharchi, Fahim Kahlouche, Youcef Benna
Abstract:
In the recent years, a considerable level of interest has been developed on the use of earth in construction, led by its rediscovery as an environmentally building material. The Stabilized Earth Concrete (SEC) is a good alternative to the cement concrete, thanks to its thermal and moisture regulating features. Many parameters affect the behavior of stabilized earth concrete. This article presents research results related to the influence of the compacting nature on some SEC properties namely: The mechanical behavior, capillary absorption, shrinkage and sustainability to water erosion, and this, basing on two types of compacting: Manual and semi-automatic.Keywords: Behavior, compacting, manual, SEC, semi-automatic.
Procedia APA BibTeX Chicago EndNote Harvard JSON MLA RIS XML ISO 690 PDF Downloads 2090