查看更多>>摘要：Use of recycled concrete aggregates (RCA) in structural concrete necessitates the understanding of complete stress-strain response of recycled aggregate concrete (RAC). An experimental and numerical investigation, was therefore, carried out to study and simulate the complete, pre-and post-peak, stress-strain response of RAC under uniaxial compression and is presented in this paper. Concrete cylinders cast with natural aggregates and RCA were tested under uniaxial compression and splitting tension to determine the compressive and splitting tensile strength along with the elastic modulus and Poisson's ratio. Experimental stress-strain curves were also produced. Cylinders were cast with different replacement percentages of RCA i.e., 0%, 30%, 50%, 70% and 100% and water-to-cement ratios of 0.43, 0.5 and 0.6. An equation for the estimation of uniaxial compressive strength of RAC has been proposed. Predicted compressive strengths compare well with the experimentally observed strengths. Experimentally measured elastic modulus and Poisson's ratio along with estimated compressive strengths were used in the elasto-damage constitutive model, proposed previously by the authors, to compare the stress-strain curves predicted by the model with the experimental stress-strain curves for uniaxial state of stress. Overall comparison of predicted stress-strain curves was found to be in good agreement with the experimentally exhibited stress-strain curves.
查看更多>>摘要：Use of recycled concrete aggregates (RCA) in structural concrete necessitates the understanding of complete stress-strain response of recycled aggregate concrete (RAC). An experimental and numerical investigation, was therefore, carried out to study and simulate the complete, pre-and post-peak, stress-strain response of RAC under uniaxial compression and is presented in this paper. Concrete cylinders cast with natural aggregates and RCA were tested under uniaxial compression and splitting tension to determine the compressive and splitting tensile strength along with the elastic modulus and Poisson's ratio. Experimental stress-strain curves were also produced. Cylinders were cast with different replacement percentages of RCA i.e., 0%, 30%, 50%, 70% and 100% and water-to-cement ratios of 0.43, 0.5 and 0.6. An equation for the estimation of uniaxial compressive strength of RAC has been proposed. Predicted compressive strengths compare well with the experimentally observed strengths. Experimentally measured elastic modulus and Poisson's ratio along with estimated compressive strengths were used in the elasto-damage constitutive model, proposed previously by the authors, to compare the stress-strain curves predicted by the model with the experimental stress-strain curves for uniaxial state of stress. Overall comparison of predicted stress-strain curves was found to be in good agreement with the experimentally exhibited stress-strain curves.
查看更多>>摘要：The present paper deals the time-dependent mixed convection Casson type MHD nanofluid flow with motile microorganisms around a spinning body adopting laminar boundary layer theory. Dynamic flow dependent on time is taken into account. The guiding partial differential structure has been converted into ordinary differential structure via similarity transformations. The numerical results of ordinary differential equations have been acquired by using shooting technique via MATLAB software. Aspects of such physical parameters have been discussed and clarified in details using tables and graphs. The effect of different parameters such as acceleration parameter on primary velocity, secondary velocity, temperature function, non-dimensional nanoparticle concentration. Comparison with previous studies is also mentioned and it is noted that a good agreement with published literature.
查看更多>>摘要：The present paper deals the time-dependent mixed convection Casson type MHD nanofluid flow with motile microorganisms around a spinning body adopting laminar boundary layer theory. Dynamic flow dependent on time is taken into account. The guiding partial differential structure has been converted into ordinary differential structure via similarity transformations. The numerical results of ordinary differential equations have been acquired by using shooting technique via MATLAB software. Aspects of such physical parameters have been discussed and clarified in details using tables and graphs. The effect of different parameters such as acceleration parameter on primary velocity, secondary velocity, temperature function, non-dimensional nanoparticle concentration. Comparison with previous studies is also mentioned and it is noted that a good agreement with published literature.
查看更多>>摘要：The use of fibers in concrete to prevent fractures and extend the joint seam space of concrete slabs is becoming more common in concrete pavements and bridge structures. However, their durability behavior against acid rain attacks and chloride ion penetration has been less studied. The current paper investigates how Fiber-Reinforced Concrete (FRC) containing 15% cementitious material (Metakaolin and Pumice) instead of Portland cement performs with respect to acid attack by using microstructure studies. In addition, the chloride penetration under marine environments was studied by simulating the tidal and immersion conditions. Durability findings demonstrate that Metakaolin and Pumice have a considerable impact on enhancing chloride penetration in marine environments. However, concrete with cementitious material shows a negative performance against acid attacks. From this research, Computed Tomography (CT) scan analysis and microstructure results show a porous structure in specimens containing admixture, and the Ca/Si ratio is decreased significantly due to decalcification.
查看更多>>摘要：The use of fibers in concrete to prevent fractures and extend the joint seam space of concrete slabs is becoming more common in concrete pavements and bridge structures. However, their durability behavior against acid rain attacks and chloride ion penetration has been less studied. The current paper investigates how Fiber-Reinforced Concrete (FRC) containing 15% cementitious material (Metakaolin and Pumice) instead of Portland cement performs with respect to acid attack by using microstructure studies. In addition, the chloride penetration under marine environments was studied by simulating the tidal and immersion conditions. Durability findings demonstrate that Metakaolin and Pumice have a considerable impact on enhancing chloride penetration in marine environments. However, concrete with cementitious material shows a negative performance against acid attacks. From this research, Computed Tomography (CT) scan analysis and microstructure results show a porous structure in specimens containing admixture, and the Ca/Si ratio is decreased significantly due to decalcification.
Son, Le TruongTho, Nguyen ChiChinh, Van MinhVan Thom, Do...
527-536页
查看更多>>摘要：This work examines the dynamic response of nanoplates by including the flexomagnetic effect based on the novel shear deformation theory. The plate's equilibrium equation is shown by using the concept of virtual work to solve the equation. The novelty of this work is to show the influence of the flexomagnetic effect on the displacement, velocity, and acceleration responses of nanoplates when subjected to time-varying loads. This study employs the finite element approach, using four nodal elements, each having six degrees of freedom. The finite element model in this study has been validated for dependability by comparison with previously reported findings. This research uses numerical calculations to demonstrate how geometric dimensions, material properties, and frequency of external pressures affect the dynamic response of nanostructures. This study is valuable for designers seeking to optimize the creation of nanoplates for practical use.
Son, Le TruongTho, Nguyen ChiChinh, Van MinhVan Thom, Do...
527-536页
查看更多>>摘要：This work examines the dynamic response of nanoplates by including the flexomagnetic effect based on the novel shear deformation theory. The plate's equilibrium equation is shown by using the concept of virtual work to solve the equation. The novelty of this work is to show the influence of the flexomagnetic effect on the displacement, velocity, and acceleration responses of nanoplates when subjected to time-varying loads. This study employs the finite element approach, using four nodal elements, each having six degrees of freedom. The finite element model in this study has been validated for dependability by comparison with previously reported findings. This research uses numerical calculations to demonstrate how geometric dimensions, material properties, and frequency of external pressures affect the dynamic response of nanostructures. This study is valuable for designers seeking to optimize the creation of nanoplates for practical use.
查看更多>>摘要：This study focuses on to predict the ultimate shear strength of steel fiber reinforced concrete (SFRC) slender and deep beams without stirrups using the gene expression programming (GEP). For this purpose, a large database containing 437 shear strength tests of SFRC beams that failed in shear mode were divided into two different groups according to their span-depth ratios and two different models were developed for slender and deep beams. The effective depth of beam (d), longitudinal reinforcement ratio (rho), shear span to effective depth ratio (a/d), compressive strength of concrete (f(c)'), fiber volume percentage V-f)and fiber factor (F) were considered as input parameters in GEP models. The results of the proposed models were compared to those of the existing models in the literature. It was concluded that the proposed models provide the best performance and accuracy for the shear strength of both slender and deep beams. Furthermore, sensitivity and parametric analysis were performed separately to evaluate the influence of input parameters on the shear strengths of both slender and deep SFRC beams.
查看更多>>摘要：This study focuses on to predict the ultimate shear strength of steel fiber reinforced concrete (SFRC) slender and deep beams without stirrups using the gene expression programming (GEP). For this purpose, a large database containing 437 shear strength tests of SFRC beams that failed in shear mode were divided into two different groups according to their span-depth ratios and two different models were developed for slender and deep beams. The effective depth of beam (d), longitudinal reinforcement ratio (rho), shear span to effective depth ratio (a/d), compressive strength of concrete (f(c)'), fiber volume percentage V-f)and fiber factor (F) were considered as input parameters in GEP models. The results of the proposed models were compared to those of the existing models in the literature. It was concluded that the proposed models provide the best performance and accuracy for the shear strength of both slender and deep beams. Furthermore, sensitivity and parametric analysis were performed separately to evaluate the influence of input parameters on the shear strengths of both slender and deep SFRC beams.
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