Computers and Concrete最新文献

{"title":"Effect of basalt fiber on the freeze-thaw resistance of recycled aggregate concrete","authors":"Yahong Ding, Shuqi Guo, Xianggang Zhang, M. Zhang, J. Wu","doi":"10.12989/CAC.2021.28.2.115","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.115","url":null,"abstract":"Recycled aggregate concrete (RAC) is considered a good way of sustainable development, but compared with natural coarse aggregates (NCA), the performance of recycled coarse aggregates (RCA) is often worse. This study aimed at the basalt fiber (BF) enhances the frost resistance of RAC. Therefore, a rapid freeze-thaw cycles test was carried out on basalt fiber reinforced recycled aggregate concrete (BFRRC), with the variation of three different replacement ratios of RCA (i.e., 0, 50 and 100%) and four different contents of BF (i.e., 0, 2, 4 and 6 kg/m3). Then, the damage appearance, mass losses, and relative dynamic elastic modulus (RDEM) of specimens were analyzed. Results were showed that the appearance damage characteristics of RAC are different from NAC, as the replacement ratio of RCA was increased, the damage appearance of the specimens was exacerbated, and surface spalling transformed into corner spalling and holes were generated in the surfaces of the specimens. Compared with mass loss, REDM can better reflect the frost resistance of BFRRC. BF could significantly improve the damage appearance and RDEM loss of the specimens, incorporating 4 kg/m3 of BF can significantly improve the frost resistance of RAC. In addition, the mechanism of freeze–thaw damage was revealed by using scanning electron microscopy (SEM) and damage theory, a freeze–thaw damage model of BFRRC was established by defining the damage degree on the basis of the RDEM. The results of this work could provide a reference for the further research and engineering application of BFRRC.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"10 1","pages":"115"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"84817290","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}

{"title":"A coupled experimental and numerical simulation of concretejoints' behaviors in tunnel support using concrete specimens","authors":"F. Zhou, V. Sarfarazi, H. Haeri, Mohammad Hosein Soleymanipargoo, J. Fu, M. F. Marji","doi":"10.12989/CAC.2021.28.2.189","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.189","url":null,"abstract":"The experimentally tested modelled specimens were simulated by a two-dimensional particle flow code to study the behavior of rock mass surrounding a tunnel interacted with a nearby rock joint or discontinuity. The specially prepared specimens are tested in the laboratory and the measured results are provided. Then a numerical modelling of these tests is accomplished by a calibrated two-dimensional particle flow code to study the rock tunnel behavior while interacting with a neighboring joint. The two-dimensional discrete element code was calibrated using Brazilian tensile test. Then the modelled specimens are provided so that various configurations of tunnel cross sections and the neighboring joints were tested under uniaxial compression condition. This study showed that the tensile cracks are the most dominant mode occurred in these modelled samples. The wing cracks initiated from the joint tips when the joints interacted in a position less than that of the tunnel height. These cracks are then propagated and interacted with the tunnel ceiling. When the joint interacting the tunnel head and the interaction angle is negative the tunnel can be in a stable position considering the joints effect on its instability situation. But for positive interaction angles and the case of joint existing near the tunnel head, the wing cracks may initiate and propagate towards the tunnel ceiling. As the distance of joint from the tunnel ceiling is increased its effect on the tunnel instability is decreased because the failure stress is increased. The number of joints and their distance with the tunnel boundary (ceiling) have also a profound effect on the stability condition of the tunnel. The failure stress reached its maximum value for the increase from -30 to -60 degrees or increase from 30 to 60 degrees. The failure stress also decreased as the number of notches and their lengths increased. In all these interaction scenarios, the corresponding numerical and experimental values compared and it is concluded that the failure stresses are very close to each other which verified the accuracy and applicability of the proposed modeling technic.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"21 1","pages":"189"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83282576","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}

{"title":"Bond behavior of FRP bars in CR concrete","authors":"Jiongfeng Liang, Jianguo Liu, Lifei Fan, R. Ren, Wei Li, Wen-rui Yang","doi":"10.12989/CAC.2021.28.2.107","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.107","url":null,"abstract":"This paper evaluated the bond behavior between recycled crumb rubber (CR) concrete and fiber reinforced polymer (FRP) bar. An experimental study consisting of fifty-seven pull-out specimens with fine recycled crumb rubber aggregate content of 0%, 5%,10% and 15% was described. The results showed that recycled crumb rubber concrete pull-out specimens exhibited similar bond stress-slip curves, which had four stages: the micro-slip, concrete internal cracking, pullout and residual stages. The use of crumb rubber in concrete reduced the bond strength. The bond strength decreased with the increase of the compressive strength of recycled crumb rubber concrete. The type and content of recycled crumb rubber also affected the bond strength. The glass fiber reinforced polymer (GFRP) bars tended to have stronger bonds than that of basalt fiber reinforced polymer (BFRP) bars.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"44 1","pages":"107"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"72706019","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}

{"title":"The utility of proper orthogonal decomposition for dimensionality reduction in understanding behavior of concrete","authors":"A. Manoj, K. Narayan","doi":"10.12989/CAC.2021.28.2.129","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.129","url":null,"abstract":"Properties of wet and set concrete are influenced by a wide range of variables. With new formulations being tried and adopted, understanding workability, strength and durability characteristics of these formulations is of utmost importance. From among the wide range of variables that affect properties of concrete, identification of the most vital, interplay between variables, quantification of influence, for judicious manipulation of mix proportioning, placement, compaction and curing, to get the desired and targeted end results can vastly be improved by employing the state of the art data handling tools. Group method of data handling (GMDH), a set of mathematical algorithms, is of great usage potential in multi-variable data modeling, optimization and pattern recognition. Proper Orthogonal Decomposition (POD) a subset of GMDH, a technique for systematic dimensionality reduction and pattern recognition, is of great importance in studying complex datasets. This paper presents the need for adoption of GMDH techniques in concrete technology with an account of trends in this direction and also provides an illustration of POD's utility as a valid decision-making tool in dimensionality reduction and projection of behavior of concrete subjected to elevated temperature.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"55 1","pages":"129"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"90460791","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}

{"title":"Efficient soft computing techniques for the prediction of compressive strength of geopolymer concrete","authors":"Rahul Biswas, A. Bardhan, P. Samui, B. Rai, Subrata Nayak, D. J. Armaghani","doi":"10.12989/CAC.2021.28.2.221","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.2.221","url":null,"abstract":"In the recent year, extensive researches have been done on fly ash-based geopolymer concrete for its similar properties like Portland cement as well as its environmental sustainability. However, it is difficult to provide a consistent method for geopolymer mix design because of the complexity and uncertainty of its design parameters, such as the alkaline solution concentration, mole ratio, and liquid to fly ash mass ratio. These mix-design parameters, along with the curing time and temperature ominously affect the most significant properties of the geopolymer concrete, i.e., compressive strength. To overcome these difficulties, the paper aims to provide a simple mix-design tool using artificial intelligence (AI) models. Three well-established and efficient AI techniques namely, genetic programming, relevance vector machine, and Gaussian process regression are used. Based on the performance of the developed models, it is understood that all the models have the capability \u0000to deliver higher prediction accuracies in the range of 0.9362 to 0.9905 (based on R2 value). Among the employed models, RVM outperformed the other model with R2=0.9905 and RMSE=0.0218. Theodore, the developed RVM model is very potential to be a new alternative to assist engineers to save time and expenditure on account of the trial-and-error process in finding the correct design mix proportions.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"116 1","pages":"221"},"PeriodicalIF":4.1,"publicationDate":"2021-08-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"87698354","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}

{"title":"A novel approach to the complete stress strain curve for plastically damaged concrete under monotonic and cyclic loads","authors":"Trong Nghia-Nguyen, Thanh Cuong-Le, S. Khatir, M. Wahab","doi":"10.12989/CAC.2021.28.1.039","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.1.039","url":null,"abstract":"In this paper, new analytical formulations, which can be easily applied to normal and high-strength concretes under \u0000monotonic compressive and direct tensile loads, are proposed. Moreover, plastic damage model for concrete under uniaxial cyclic loading is also employed by introducing a simple damage function. The majority of published material models focuses on a certain type of concrete based on their testing results, which can be hardly applied to other types of concrete such as normal or high strength concrete. This paper presents a novel approach that can be applied to different types of concrete and highlights that the differences among testing results may come from the variations of strain at the peak stress. The damage phenomenon of concrete is simplified by a non-linear degradation of elastic modulus function, which in turn creates a linear stress-strain relation under cyclic loading. The damage function can be easily and quickly used to calibrate concrete properties for plastic damage \u0000model, which is very useful for industrial applications. Finally, the accuracy and pre-eminence of the proposed damage model are verified through comparison with experimental data and analytical solutions.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"12 1","pages":"39-53"},"PeriodicalIF":4.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"75792008","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}

{"title":"Strength performance with buckling analysis of Intermediate filaments by consideration nonlocal parameters","authors":"M. Safeer, M. Khadimallah, M. Taj, M. Hussain, Elimame Elaloui, A. Tounsi","doi":"10.12989/CAC.2021.28.1.069","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.1.069","url":null,"abstract":"Protein structures, that form intermediate filaments (IFs) was first found by an experiment known as the computerized analysis of amino acid sequence of a human epidermal keratin derived from cloned cDNAs. This study is made by \u0000the application of Euler beam theory. The buckling of intermediate filaments is studied keeping the nonlocal effects under consideration. It is observed that the nonlocal parameter has a great impact on the dynamics of intermediate filaments. The buckling behavior of intermediate filaments is investigated with different four conditions like as simply supported, clamped, cantilever and propped cantilever beam. Also the effect of critical bucking force is seen for different strengths of nonlocal \u0000parameter as 1,2,3,4.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"9 1","pages":"69"},"PeriodicalIF":4.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"86199876","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}

{"title":"Investigation of the effects of corrosion on bond strength of steel in concrete using neural network","authors":"N. Concha, A. Oreta","doi":"10.12989/CAC.2021.28.1.077","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.1.077","url":null,"abstract":"Corrosion of steel reinforcement due to hostile environments is regarded as one vital structural health concerns in concrete structures. Specifically, the development of corrosion affects the necessary bond strength of rebar in concrete contributing to the loss of resilience and possible structural failures. It is thus essential to understand the effects of corrosion on bond strength so that remedial measures can be done on existing and deteriorating RC structures. Hence, this study investigated through laboratory experiments and Artificial Neural Network (ANN) modeling the effects of corrosion on bond strength. Experimental results showed that at small amounts of corrosion less than 0.27%, the bond strength was observed to increase. At these levels, the amounts of corrosion products were sufficient enough to expand freely through the permeable structure of concrete and occupy the pore spaces. Beyond this level, however, the bond strength of concrete deteriorated significantly. There was an observed average decrease of 1.391 MPa in the bond strength values for every percent increase in the amount of corrosion. The expansive and progressive internal radial stress due to corrosion resulted to the development of internal and surface cracks in concrete. In the parametric investigation of the derived ANN model, the bond strength was also observed to decline continuously with the growth of corrosion derivatives as represented by the relative magnitudes of the ultrasonic pulse velocity (UPV). The prediction results of the model can be utilized as basis for design and select appropriate mitigating measures to prolong the service life of concrete structures.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"197 1","pages":"77-91"},"PeriodicalIF":4.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"83097056","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}

{"title":"Enhancing the performance of hyposludge concrete beams using basalt fiber and latex under cyclic loading","authors":"S. Srividhya, R. Vidjeapriya, M. Neelamegam","doi":"10.12989/CAC.2021.28.1.093","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.1.093","url":null,"abstract":"An attempt has been made to study the influence of basalt fiber and latex on the behaviour of hypo sludge based \u0000concrete beams under cyclic loading. Two sets of four geometrically similar specimens were cast to study the deflection behaviour of beams. The analysis and study of parameters such as ultimate load carrying capacity, crack pattern, energy dissipation, stiffness degradation and ductility were conducted in this investigation. A preliminary investigation showed that the durability properties decreased when hypo sludge was added to concrete. To enhance the durability, SBR latex was added to one set of four specimens. Results indicate that the addition of basalt fibers and latex to the hypo sludge based concrete beams showed significant improvement in ultimate load carrying capacity, stiffness, energy dissipation and ductility compared to the control concrete beams. The specimen (LHSBFC) with 10% hypo sludge, 0.25% Basalt fiber and 10% SBR latex showed an increase of 1.82% load carrying capacity, 2.65% stiffness, 21.84% ductility, 16% energy dissipation when compared to the control concrete beam.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"79 1","pages":"93-105"},"PeriodicalIF":4.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88153868","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}

{"title":"Experimental study and modeling on stress-strain curve of sulfate-corroded concrete","authors":"Guangji Yin, X. Zuo, Xiao D. Wen, Yu-Juan Tang","doi":"10.12989/CAC.2021.28.1.001","DOIUrl":"https://doi.org/10.12989/CAC.2021.28.1.001","url":null,"abstract":"The stress-strain curve of concrete under a uniaxial compression can reflect much information about its mechanical properties. This paper performs an experimental study and modeling on the stress-strain curve of concrete subjected to external sulfate attack (ESA). To shorten the experimental period, cement mortar specimen (CMS) with a small size is selected as research objected, and is immersed into purified water, 2.5% and 5.0% Na2SO4 solution. First, an economic test equipment is designed by adding rigid elements to ordinary hydraulic testing machine. Second, the evolution of stress-strain curve and mechanical properties of sulfate-corroded CMS with immersion time is obtained. Based on least-square method, the expressions of two chemical damage parameters are determined to respectively characterize the time-varying elastic modulus and compression strength of CMS caused by ESA. Then, a coupling chemo-mechanical damage constitutive model for sulfatecorroded CMS is established by introducing the chemical damage parameters. Finally, the numerical solution of the model is presented, and is validated by the above experimental data of stress-strain curve of CMS.","PeriodicalId":50625,"journal":{"name":"Computers and Concrete","volume":"38 1","pages":"1"},"PeriodicalIF":4.1,"publicationDate":"2021-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"88419712","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}