2D,3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made with different cement replacement percentage by fly ash （0%,10%,20%,40%,60%）,water to binder ...2D,3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made with different cement replacement percentage by fly ash （0%,10%,20%,40%,60%）,water to binder ratios （0.3,0.35,0.4）,and curing ages （28 d,90 d）.An interaction effect caused by 2D and 3D diffusion could obviously be observed through the comparison with 1D testing results.In order to quantify the interaction effect,2D and 3D diffusion interaction coefficients was proposed in this paper.Finally,the changes of 2D and 3D interaction coefficients with the change in the free chloride ion concentration were given.The above research provide an insight into chloride ion attack on the edge and corner reinforcing bars of concrete structures in the field of civil engineering.展开更多
Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine...Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow,lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity (Sr/Ba) , alkalinity ( Ca + Mg)/(Si + Al) , reducibility (Ni + Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz -section to be represented for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratigraphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Carnian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epicontinental (cratonic) central Europe Basin. It covered the area in between Great Britain, North Sea, Poland and Southern Germany. It is composed of cyclic deposits of multicolored mudstones, gypsum/anhydrite, and dolomite beds. The two cases of marine ingression - influenced sequences share some common features.展开更多
Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted.However,these previous studies did not consider the effects of climate change,such as acceleration in the deteriorati...Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted.However,these previous studies did not consider the effects of climate change,such as acceleration in the deterioration of durability,on mixture design.This study presents a procedure for the optimal mixture design of termary blended concrete considering climate change and durability.First,the costs of CO2 emissions and material are calculated based on the concrete mixture and unit prices.Total cost is equal to the sum of material cost and CO2 emissions cost,and is set as the objective function of the optimization.Second,strength,slump,carbonation,and chloride ingress models are used to evaluate concrete properties.The effect of different climate change scenarios on carbonation and chloride ingress is considered.A genetic algorithm is used to find the optimal mixture considering various constraints.Third,ilustrative examples are shown for mixture design of ternary blended concrete.The analysis results show that for termary blended concrete exposed to an atmospheric environment,a rich mix is necessary to meet the challenge of climate change,and for termary blended concrete exposed to a marine environment,the impact of climate change on mixture design is marginal.展开更多
An investigation on chloride ingress and macro-cell corrosion of steel bars in concrete made with recycled brick aggregate(RBA)was carried out.As control cases,virgin brick aggregate(BA)and stone aggregate(SA)were als...An investigation on chloride ingress and macro-cell corrosion of steel bars in concrete made with recycled brick aggregate(RBA)was carried out.As control cases,virgin brick aggregate(BA)and stone aggregate(SA)were also investigated.Both cylindrical and cracked prism specimens were studied for 16 different cases.The prism specimens were made with a segmented steel bar providing electrical connection from outside of the specimens to measure macro-cell corrosion current continuously under seawater splash exposure for a period of 30 d using a data logger.Cylindrical specimens were submerged in 3%NaCl solution at a temperature of 40℃ to investigate chloride ingress in concrete made with RBA,BA,and SA after 120 and 180 d.Half-cell potential,corrosion area,and depths of corrosion were also investigated.The chloride ingress as well as corrosion of steel bars in concrete made with the different types of aggregate is ordered as RBA>BA>SA.展开更多
基金Funded by National Natural Science Fundation of China (No.51178106)Open Program from Guangxi Key Laboratory of Disaster Prevention and Reduction (No.2008TMKF009)+1 种基金973 Program (No.2009CB623200)Program for New Century Excellent Talentsin University
文摘2D,3D chloride ion concentration at the edge and corner zones were systematically investigated for fly ash concretes made with different cement replacement percentage by fly ash （0%,10%,20%,40%,60%）,water to binder ratios （0.3,0.35,0.4）,and curing ages （28 d,90 d）.An interaction effect caused by 2D and 3D diffusion could obviously be observed through the comparison with 1D testing results.In order to quantify the interaction effect,2D and 3D diffusion interaction coefficients was proposed in this paper.Finally,the changes of 2D and 3D interaction coefficients with the change in the free chloride ion concentration were given.The above research provide an insight into chloride ion attack on the edge and corner reinforcing bars of concrete structures in the field of civil engineering.
基金NSFC (National Science Foundation of China) Project No. 4967212, attained with the assistance of the AvH (Alexander von Humboldt Foundation) of Germany.
文摘Songliao Basin is filled predominantly with continental facies sediments including alluvial fan, fluvial plain, fan delta, lacustrine delta, shore - shallow lacustrine, beach salty flat, semi - deep to deep lacustrine, subaqueous gravity flow,lacustrine swamp and pyroclastic sediments. However, some event units were formed during lake - marine linking periods of the Mid - Cretaceous in the basin, which include black shales with high values for salinity (Sr/Ba) , alkalinity ( Ca + Mg)/(Si + Al) , reducibility (Ni + Zn)/Ga and sulfide sulfur as well as heavy isotopes. The Breitenholz -section to be represented for facies comparison with the Cretaceous evaporitic series in Northeast China is localized in Southwest Germany. Stratigraphically it belongs to the Crabfeld Formation of Keuper of the Germanic Triassic corresponding to Ladinian - Carnian of the international reference scale, and is generally called Lower Gipskeuper. The Germanic Triassic was deposited in the epicontinental (cratonic) central Europe Basin. It covered the area in between Great Britain, North Sea, Poland and Southern Germany. It is composed of cyclic deposits of multicolored mudstones, gypsum/anhydrite, and dolomite beds. The two cases of marine ingression - influenced sequences share some common features.
基金This research was supported by the Basic Science Research Program through the National Research Foundation of Korea(NRF)funded by the Ministry of Science,ICT&Future Planning(No.2015R1A5A1037548)an NRF Grant(NRF-2020R1A2C4002093)This study was supported by a 2018 Research grant(POINT)from Kangwon National University.
文摘Many studies on the mixture design of fly ash and slag ternary blended concrete have been conducted.However,these previous studies did not consider the effects of climate change,such as acceleration in the deterioration of durability,on mixture design.This study presents a procedure for the optimal mixture design of termary blended concrete considering climate change and durability.First,the costs of CO2 emissions and material are calculated based on the concrete mixture and unit prices.Total cost is equal to the sum of material cost and CO2 emissions cost,and is set as the objective function of the optimization.Second,strength,slump,carbonation,and chloride ingress models are used to evaluate concrete properties.The effect of different climate change scenarios on carbonation and chloride ingress is considered.A genetic algorithm is used to find the optimal mixture considering various constraints.Third,ilustrative examples are shown for mixture design of ternary blended concrete.The analysis results show that for termary blended concrete exposed to an atmospheric environment,a rich mix is necessary to meet the challenge of climate change,and for termary blended concrete exposed to a marine environment,the impact of climate change on mixture design is marginal.
文摘An investigation on chloride ingress and macro-cell corrosion of steel bars in concrete made with recycled brick aggregate(RBA)was carried out.As control cases,virgin brick aggregate(BA)and stone aggregate(SA)were also investigated.Both cylindrical and cracked prism specimens were studied for 16 different cases.The prism specimens were made with a segmented steel bar providing electrical connection from outside of the specimens to measure macro-cell corrosion current continuously under seawater splash exposure for a period of 30 d using a data logger.Cylindrical specimens were submerged in 3%NaCl solution at a temperature of 40℃ to investigate chloride ingress in concrete made with RBA,BA,and SA after 120 and 180 d.Half-cell potential,corrosion area,and depths of corrosion were also investigated.The chloride ingress as well as corrosion of steel bars in concrete made with the different types of aggregate is ordered as RBA>BA>SA.
