Computers and Concrete最新文献_第9页

Corrosion effects on mechanical behavior of steel fiber reinforced concrete, including fibers from recycled tires 腐蚀对钢纤维增强混凝土力学性能的影响，包括回收轮胎纤维

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-10-01 DOI: 10.12989/CAC.2020.26.4.367

M. Ansari, A. Safiey

{"title":"Corrosion effects on mechanical behavior of steel fiber reinforced concrete, including fibers from recycled tires","authors":"M. Ansari, A. Safiey","doi":"10.12989/CAC.2020.26.4.367","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.4.367","url":null,"abstract":"Today, the use of special technologies in the admixture of concrete has made tremendous progress, but the problem that has always existed in the construction of concrete members is the brittleness and lack of loading bearing after cracking, which leads to reduced strength and energy absorption. One of the best ways to fix this is to reinforce the concrete with steel fibers. Steel fibers also control cracks due to dry shrinkage, reduce structural crack width, and improve impact resistance. In this study, recycled steel fibers from worn tires have been used in the manufacture of concrete samples, the secondary benefits of which are the reduction of environmental pollution. One of the disadvantages of steel fiber reinforced concrete is the corrosion of steel fibers and their deterioration in harsh environments such as coastal areas. Corrosion caused by chlorine ions in metal fibers causes deterioration and early decommissioning of structures in corrosive environments. In this study, the effect of the dosage of steel fibers (dosages of 15, 30, and 45 kg of fibers per cubic meter of concrete) and aspect ratio of fibers (aspect ratio of 25 and 50) on compressive and flexural strength of concrete samples are investigated. In the following, the effect of fiber corrosion on the results of the mechanical properties of concrete samples is examined. The results show that the increase in fiber causes a relative increase in compressive strength, and a significant increase in flexural strength, and corrosion of steel fibers without reducing workability reduces compressive strength and flexural strength by up to 6 to 11%, respectively.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"27 1","pages":"367-375"},"PeriodicalIF":4.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75944993","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Thermal field of large-diameter concrete filled steel tubular members under solar radiation 太阳辐射下大直径钢管混凝土构件的热场

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-10-01 DOI: 10.12989/CAC.2020.26.4.343

Daigeng Yang, Guorong Chen, X. Ding, Juncai Xu

{"title":"Thermal field of large-diameter concrete filled steel tubular members under solar radiation","authors":"Daigeng Yang, Guorong Chen, X. Ding, Juncai Xu","doi":"10.12989/CAC.2020.26.4.343","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.4.343","url":null,"abstract":"Concrete-filled steel tubular (CFST) members have been widely used in engineering, and their tube diameters have become larger and larger. But there is no research on the thermal field of large-diameter CFST structure. These studies focused on the thermal field of the large-diameter CFST structure under solar radiation. The environmental factors and the actual placement position were considered, and the finite element model (FEM) of the thermal field of CFST members under solar radiation (SR) was established. Then the FEM was verified by practical experiments. The most unfavorable temperature gradient model in the cross-section was proposed. The testing results showed that the temperature field of the large-diameter CFST member section was non-linearly distributed due to the influence of SR. The temperature field results of CFST members with different pipe diameters indicated that the larger the core concrete diameter was, the slower the central temperature changed, and there was a significant temperature difference between the center and the boundary. Based on the numerical model, the most unfavorable temperature gradient model in the section was proposed. The model showed that the temperature difference around the center of the circle is small, and the boundary temperature difference is significant. The maximum temperature difference is 15.22oC, which appeared in the southern boundary area of the specimen. Therefore, it is necessary to consider the influence of SR on the thermal field of the member for large-diameter CFST members in actual engineering, which causes a large temperature gradient in the member.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"63 1","pages":"343-350"},"PeriodicalIF":4.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75083429","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

RC deep beams with unconventional geometries: Experimental and numerical analyses 具有非常规几何形状的RC深梁:实验和数值分析

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-10-01 DOI: 10.12989/CAC.2020.26.4.351

Agno Alves Vieira, G. Melo, A. Miranda

{"title":"RC deep beams with unconventional geometries: Experimental and numerical analyses","authors":"Agno Alves Vieira, G. Melo, A. Miranda","doi":"10.12989/CAC.2020.26.4.351","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.4.351","url":null,"abstract":"This work presents numerical and experimental analyses of the behavior of reinforced-concrete deep beams with unconventional geometries. The main goal here is to experimentally and numerically study these geometries to find possible new behaviors due to the material nonlinearity of reinforced concrete with complex geometries. Usually, unconventional geometries result from innovative designs; in general, studies of reinforced concrete structures are performed only on conventional members such as beams, columns, and labs. To achieve the goal, four reinforced-concrete deep beams with geometries not addressed in the literature were tested. The models were numerically analyzed with the Adaptive Micro Truss Model (AMTM), which is the proposed method, to address new geometries. This work also studied the main parameters of the constitutive model of concrete based on a statistical analysis of the finite element (FE) results. To estimate the ultimate loads, FE simulations were performed using the Monte Carlo method. Based on the obtained ultimate loads, a probabilistic distribution was created, and the final ultimate loads were computed.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"29 1","pages":"351-365"},"PeriodicalIF":4.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"79020523","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Optimization of cost and mechanical properties of concrete with admixtures using MARS and PSO 利用MARS和PSO优化外加剂混凝土的成本和力学性能

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-10-01 DOI: 10.12989/CAC.2020.26.4.309

Reza Sarkhani Benemaran, M. Esmaeili‐Falak

{"title":"Optimization of cost and mechanical properties of concrete with admixtures using MARS and PSO","authors":"Reza Sarkhani Benemaran, M. Esmaeili‐Falak","doi":"10.12989/CAC.2020.26.4.309","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.4.309","url":null,"abstract":"The application of multi-variable adaptive regression spline (MARS) in predicting he long-term compressive \u0000strength of a concrete with various admixtures has been investigated in this study. The compressive strength of concrete specimens, which were made based on 24 different mix designs using various mineral and chemical admixtures in different curing ages have been obtained. First, The values of fly ash (FA), micro-silica (MS), water-reducing admixture (WRA), coarse and fine aggregates, cement, water, age of samples and compressive strength were defined as inputs to the model, and MARS analysis was used to model the compressive strength of concrete and to evaluate the most important parameters affecting the estimation of compressive strength of the concrete. Next, the proposed equation by the MARS method using particle swarm \u0000optimization (PSO) algorithm has been optimized to have more efficient equation from the economical point of view. The proposed model in this study predicted the compressive strength of the concrete with various admixtures with a correlation coefficient of R=0.958 rather than the measured compressive strengths within the laboratory. The final model reduced the production cost and provided compressive strength by reducing the WRA and increasing the FA and curing days, simultaneously. It was also found that due to the use of the liquid membrane-forming compounds (LMFC) for its lower cost than water spraying method (SWM) and also for the longer operating time of the LMFC having positive mechanical effects on the final concrete, the final product had lower cost and better mechanical properties.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"161 1","pages":"309-316"},"PeriodicalIF":4.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84199716","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 39

Natural time period equations for moment resisting reinforced concrete structures comprising hollow sections 包含空心截面的抗弯矩钢筋混凝土结构的自然周期方程

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-10-01 DOI: 10.12989/CAC.2020.26.4.317

S. Prajapati, H. Far, M. Aghayarzadeh

{"title":"Natural time period equations for moment resisting reinforced concrete structures comprising hollow sections","authors":"S. Prajapati, H. Far, M. Aghayarzadeh","doi":"10.12989/CAC.2020.26.4.317","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.4.317","url":null,"abstract":"A precise estimation of the natural time period of buildings improves design quality, causes a significant reduction of the buildings' weight, and eventually leads to a cost-effective design. In this study, in order to optimise the reinforced concrete frames design, some symmetrical and unsymmetrical buildings composed of solid and hollow members have been simulated using finite element software SAP 2000. In numerical models, different parameters such as overturning moment, story drift, deflection, base reactions, and stiffness of the buildings were investigated and the results have been compared with strength and serviceability limit criteria proposed by Australian Standard (AS 3600 2018). Comparing the results of the numerical modelling with existing standards and performing a cost analysis proved the merits of hollow box sections compared to solid sections. Finally, based on numerical simulation results, two equations for natural time period of moment resisting reinforced concrete buildings have been presented. Both derived equations reflected higher degree of correlation and reliability with different complexities of building when compared with existing standards and relationships provided by other scholars. Therefore, these equations will assist practicing engineers to predict elastic behaivour of structures more precisely.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"15 1","pages":"317-325"},"PeriodicalIF":4.1,"publicationDate":"2020-10-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"74158804","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 0

Deflections, stresses and free vibration studies of FG-CNT reinforced sandwich plates resting on Pasternak elastic foundation 基于帕斯捷尔纳克弹性地基的FG-CNT增强夹层板挠度、应力及自由振动研究

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-09-01 DOI: 10.12989/CAC.2020.26.3.213

Noureddine Bendenia, M. Zidour, A. A. Bousahla, F. Bourada, A. Tounsi, K. H. Benrahou, E. A. Bedia, S. R. Mahmoud, A. Tounsi

{"title":"Deflections, stresses and free vibration studies of FG-CNT reinforced sandwich plates resting on Pasternak elastic foundation","authors":"Noureddine Bendenia, M. Zidour, A. A. Bousahla, F. Bourada, A. Tounsi, K. H. Benrahou, E. A. Bedia, S. R. Mahmoud, A. Tounsi","doi":"10.12989/CAC.2020.26.3.213","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.3.213","url":null,"abstract":"The present study covenants with the static and free vibration behavior of nanocomposite sandwich plates \u0000reinforced by carbon nanotubes resting on Pasternak elastic foundation. Uniformly distributed (UD-CNT) and functionally \u0000graded (FG-CNT) distributions of aligned carbon nanotube are considered for two types of sandwich plates such as, the face sheet reinforced and homogeneous core and the homogeneous face sheet and reinforced core. Based on the first shear deformation theory (FSDT), the Hamilton's principle is employed to derive the mathematical models. The obtained solutions are numerically validated by comparison with some available cases in the literature. The elastic foundation model is assumed as one parameter Winkler - Pasternak foundation. A parametric study is conducted to study the effects of aspect ratios, foundation \u0000parameters, carbon nanotube volume fraction, types of reinforcement, core-to-face sheet thickness ratio and types of loads acting on the bending and free vibration analyses. It is explicitly shown that the (FG-CNT) face sheet reinforced sandwich plate has a high resistance against deflections compared to other types of reinforcement. It is also revealed that the reduction in the dimensionless natural frequency is most pronounced in core reinforced sandwich plate.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"47 1","pages":"213-226"},"PeriodicalIF":4.1,"publicationDate":"2020-09-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"76655528","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 147

Computer modeling and analytical prediction of shear transfer in reinforced concrete structures 钢筋混凝土结构剪切传递的计算机模拟与分析预测

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-08-01 DOI: 10.12989/CAC.2020.26.2.151

M. N. Kataoka, A. Debs, D. Araújo, B. Martins

引用次数: 0

Micromechanical investigation for the probabilistic behaviorof unsaturated concrete 非饱和混凝土概率行为的细观力学研究

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-08-01 DOI: 10.12989/CAC.2020.26.2.127

Qing Chen, Zhi-yuan Zhu, Fang Liu, Haoxin Li, Zheng-wu Jiang

{"title":"Micromechanical investigation for the probabilistic behaviorof unsaturated concrete","authors":"Qing Chen, Zhi-yuan Zhu, Fang Liu, Haoxin Li, Zheng-wu Jiang","doi":"10.12989/CAC.2020.26.2.127","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.2.127","url":null,"abstract":"There is an inherent randomness for concrete microstructure even with the same manufacturing process. Meanwhile, the concrete material under the aqueous environment is usually not fully saturated by water. This study aimed to develop a stochastic micromechanical framework to investigate the probabilistic behavior of the unsaturated concrete from microscale level. The material is represented as a multiphase composite composed of the water, the pores and the intrinsic concrete (made up by the mortar, the coarse aggregates and their interfaces). The differential scheme based two-level micromechanical homogenization scheme is presented to quantitatively predict the concrete's effective properties. By modeling the volume fractions and properties of the constituents as stochastic, we extend the deterministic framework to stochastic to incorporate the material's inherent randomness. Monte Carlo simulations are adopted to reach the different order moments of the effective properties. A distribution-free method is employed to get the unbiased probability density function based on the maximum entropy principle. Numerical examples including limited experimental validations, comparisons with existing micromechanical models, commonly used probability density functions and the direct Monte Carlo simulations indicate that the proposed models provide an accurate and computationally efficient framework in characterizing the material's effective properties. Finally, the effects of the saturation degrees and the pore shapes on the concrete macroscopic probabilistic behaviors are investigated based on our proposed stochastic micromechanical framework.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"12 1","pages":"127"},"PeriodicalIF":4.1,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86661010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 1

Finite element modeling of contact between an elastic layer and two elastic quarter planes 弹性层与两个弹性四分之一平面接触的有限元建模

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-08-01 DOI: 10.12989/CAC.2020.26.2.107

Murat Yaylacı, M. Avcar

{"title":"Finite element modeling of contact between an elastic layer and two elastic quarter planes","authors":"Murat Yaylacı, M. Avcar","doi":"10.12989/CAC.2020.26.2.107","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.2.107","url":null,"abstract":"In this study, a two dimensional model of receding contact problem has been analyzed using finite element method \u0000(FEM) based software ANSYS and ABAQUS. For this aim finite element modeling of elastic layer and two homogeneous, \u0000isotropic and symmetrical elastic quarter planes pressed by means of a rigid circular punch has been presented. Mass forces and friction are neglected in the solution. Since the problem is examined for the plane state, the thickness along the z-axis direction is taken as a unit. In order to check the accuracy of the present models, the obtained results are compared with the available results of the open literature as well as the results of two software are compared using Root Mean Square Error (RMSE) and good \u0000agreements are found. Numerical analyses are performed considering different values of the external load, rigid circular radius, quarter planes span length and material properties. The contact lengths and contact stresses of these values are examined, and their results are presented. Consequently, it is concluded that the considered non-dimensional quantities have noteworthy influence on the contact lengths and contact stress distributions, additionally if FEM analysis is used correctly, it can be an \u0000efficient alternative method to the analytical solutions that need time.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"74 1","pages":"107"},"PeriodicalIF":4.1,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87265822","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 34

Bond behavior of PP fiber-reinforced cinder concrete after fire exposure PP纤维增强煤渣混凝土火灾后的粘结性能

IF 4.1 4区工程技术

Computers and Concrete Pub Date : 2020-08-01 DOI: 10.12989/CAC.2020.26.2.115

B. Cai, A. Wu, F. Fu

{"title":"Bond behavior of PP fiber-reinforced cinder concrete after fire exposure","authors":"B. Cai, A. Wu, F. Fu","doi":"10.12989/CAC.2020.26.2.115","DOIUrl":"https://doi.org/10.12989/CAC.2020.26.2.115","url":null,"abstract":"To reduce the damage of concrete in fire, a new type of lightweight cinder aggregate concrete was developed due to the excellent fire resistance of cinder. To further enhance its fire resistance, Polypropylene (PP) Fibers which can enhance the fire resistance of concrete were also used in this type of concrete. However, the bond behavior of this new type of concrete after fire exposure is still unknown. To investigate its bond behavior, 185 specimens were heated up to 22, 200, 400, 600 or 800 oC for 2 h duration respectively, which is followed by subsequent compressive and tensile tests at room temperature. The concrete-rebar bond strength of C30 PP fiber-reinforced cinder concrete was subsequently investigated through pull-out tests after fire exposure. The microstructures of the PP fiber-reinforced cinder concrete and the status of the PP fibre at different temperature were inspected using an advanced scanning electron microscopy, aiming to understand the mechanism of the bonding deterioration under high temperature. The effects of rebar diameter and bond length on the bond strength of PP fiber-reinforced cinder concrete were investigated based on the test results. The bond-slip relation of PP fiber-reinforced cinder concrete after exposure at different temperature was derived based on the test results.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"1 1","pages":"115"},"PeriodicalIF":4.1,"publicationDate":"2020-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88345034","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

引用次数: 3