The effect of curing age on chloride diffusion coefficient of recycled aggregate concrete subjected to different compressive stresses was investigated.A compression loading setup was both designed and fabricated.The c...The effect of curing age on chloride diffusion coefficient of recycled aggregate concrete subjected to different compressive stresses was investigated.A compression loading setup was both designed and fabricated.The chloride diffusion coefficients of recycled aggregate concrete under compressive stresses were measured by the rapid chloride ion migration(RCM)method.The experimental results show that the chloride diffusion coefficients of recycled aggregate concrete(RAC)under different compressive stress ratios generally decrease with the increase of curing age.For RAC subjected to the same compressive stress ratios,the chloride diffusion coefficients approximately have power functions with curing ages and the relationship models are proposed.Moreover,the influence of curing age on chloride diffusion coefficient firstly decreases and then increases as the compressive stress ratio increases.展开更多
This paper describes the effects of fire on durability of reinforced concrete structures, and points out that fire not only damages the chemical composition and physical structure of concrete by high temperature, but ...This paper describes the effects of fire on durability of reinforced concrete structures, and points out that fire not only damages the chemical composition and physical structure of concrete by high temperature, but also leads to an additional risk due to the generation of polyvinyl chloride (PVC) combustion gases. A mathematical model is proposed to calculate chloride ingress profiles in fire damaged concrete, so as to explore the service life prediction of the structure. Rapid Chloride Migration (RCM) test was carried out to determine the chloride diffusion coefficients for the application of the mathematical model. Finally, the detected results of a reported case testified to the validity of the mathematical model.展开更多
This paper applies the Debye-Hückel-Onsager electrolyte solution theory to investigate the diffusivity of ions in concrete pore solutions.First,a model of the diffusion coefficient associated with the ionic speci...This paper applies the Debye-Hückel-Onsager electrolyte solution theory to investigate the diffusivity of ions in concrete pore solutions.First,a model of the diffusion coefficient associated with the ionic species,solution concentration and ambient temperature is proposed in the saturated concrete.Secondly,as an example,the effects of sodium chloride solution concentration,which are associated with influencing factors such as the ionic cloud radius,electrophoresis and relaxation,on the chloride diffusion coefficient are analyzed.It is found that the diffusion coefficient decreases with the increase in solution concentration,and the electrophoresis and ionic cloud radius are two important factors influencing the ionic diffusivity.Finally,the experiments,in which the chloride diffusion coefficients in specimens under different water-cement ratios are measured by the rapid chloride migration（RCM）method,are carried out to validate the effectiveness of the proposed model,and the results indicate that there is a generally reasonable agreement between the experimental and the proposed model results.展开更多
基金supported by the Fundamental Research Funds for the Central UniversitiesFoundation of Graduate Innovation Center in Nanjing University of Aeronautics and Astronautics (No.kfjj20150105)the National Natural Science Foundation of China (No. 51279074)
文摘The effect of curing age on chloride diffusion coefficient of recycled aggregate concrete subjected to different compressive stresses was investigated.A compression loading setup was both designed and fabricated.The chloride diffusion coefficients of recycled aggregate concrete under compressive stresses were measured by the rapid chloride ion migration(RCM)method.The experimental results show that the chloride diffusion coefficients of recycled aggregate concrete(RAC)under different compressive stress ratios generally decrease with the increase of curing age.For RAC subjected to the same compressive stress ratios,the chloride diffusion coefficients approximately have power functions with curing ages and the relationship models are proposed.Moreover,the influence of curing age on chloride diffusion coefficient firstly decreases and then increases as the compressive stress ratio increases.
基金Project (No. 50538070) supported by the National Natural ScienceFoundation of China
文摘This paper describes the effects of fire on durability of reinforced concrete structures, and points out that fire not only damages the chemical composition and physical structure of concrete by high temperature, but also leads to an additional risk due to the generation of polyvinyl chloride (PVC) combustion gases. A mathematical model is proposed to calculate chloride ingress profiles in fire damaged concrete, so as to explore the service life prediction of the structure. Rapid Chloride Migration (RCM) test was carried out to determine the chloride diffusion coefficients for the application of the mathematical model. Finally, the detected results of a reported case testified to the validity of the mathematical model.
基金The National Basic Research Program of China(973Program)(No.2009CB623203)the National Natural Science Foundation of China(No.51078186)+2 种基金Program for Special Talents in Six Fields of Jiangsu Province(No.2008169)the Natural Science Foundation of Jiangsu Province(No.BK2010071)China Postdoctoral Science Foundation(No.200902500)
文摘This paper applies the Debye-Hückel-Onsager electrolyte solution theory to investigate the diffusivity of ions in concrete pore solutions.First,a model of the diffusion coefficient associated with the ionic species,solution concentration and ambient temperature is proposed in the saturated concrete.Secondly,as an example,the effects of sodium chloride solution concentration,which are associated with influencing factors such as the ionic cloud radius,electrophoresis and relaxation,on the chloride diffusion coefficient are analyzed.It is found that the diffusion coefficient decreases with the increase in solution concentration,and the electrophoresis and ionic cloud radius are two important factors influencing the ionic diffusivity.Finally,the experiments,in which the chloride diffusion coefficients in specimens under different water-cement ratios are measured by the rapid chloride migration（RCM）method,are carried out to validate the effectiveness of the proposed model,and the results indicate that there is a generally reasonable agreement between the experimental and the proposed model results.
