期刊：
International Journal of Electrochemical Science,2018年13(1):498-513 ISSN：1452-3981
通讯作者：
Shi, Xianming
作者机构：
[Tong, Yangyang; Lit, Zhipeng; Gong, Jing; Shen, Zhang] Wuhan Polytech Univ, Sch Civil Engn & Architecture, Wuhan 430023, Hubei, Peoples R China.;[Shi, Xianming] Washington State Univ, Dept Civil & Environm Engn, Lab Corros Sci & Electrochem Engn, POB 642910, Pullman, WA 99164 USA.
通讯机构：
[Shi, Xianming] W;Washington State Univ, Dept Civil & Environm Engn, Lab Corros Sci & Electrochem Engn, POB 642910, Pullman, WA 99164 USA.
关键词：
Electrical injection of corrosion inhibitor (EICI);Electrochemical chloride extraction (ECE);Finite element modeling;Rebar corrosion;Repair mortar
摘要：
Repair mortar is commonly used to rehabilitate reinforced concrete structures or components that exhibit a relatively high level of distresses. Yet, the repair mortar can be contaminated by salt from its service environment. This work employs a two-dimensional finite element model to investigate the non-stationary transport behavior of ionic species in salt-contaminated and water-saturated repair mortar under an externally applied electric field. The model was experimentally validated and then utilized to evaluate the effectiveness of electrochemical chloride extraction (ECE) with or without electrical injection of corrosion inhibitor (EICI). In the case study, both the ECE alone and the simultaneous ECE+EICI treatment was found effective in decontaminating the zone in front of the steel rebar. In both techniques, the magnitude of current density had a significant effect on removing chloride out of the mortar and increasing the pH of the pore solution near the rebar, whereas the treatment time did not have a significant effect under some scenarios. The injection of the organic corrosion inhibitor significantly slowed down the removal of chloride. Changes in the ionic distribution in the mortar were generally beneficial in reducing the corrosion risk of the steel rebar and thus extending the service life of the repair mortar.
摘要：
Ordinary concrete was modified with additions of superabsorbent polymers (SAPs). Research was conducted to assess the weight loss ratio from cyclic freeze-thaw tests, the shrinkage ratio, and the sulfate attack resistance coefficient of compressive strength for the modified concrete. The results indicate that freeze-thaw resistance, shrinkage resistance, and sulfate attack resistance were greatly improved when compared to the control concrete. At the same time, the microstructure of concrete modified with SAPs was examined using scanning electron microscopy (SEM). The SEM results revealed a modification mechanism of the treated concrete. Ordinary concrete was modified with additions of superabsorbent polymers (SAPs). Research was conducted to assess the weight loss ratio from cyclic freeze-thaw tests, the shrinkage ratio, and the sulfate attack resistance coefficient of compressive strength for the modified concrete. The results indicate that freeze-thaw resistance, shrinkage resistance, and sulfate attack resistance were greatly improved when compared to the control concrete. At the same time, the microstructure of concrete modified with SAPs was examined using scanning electron microscopy (SEM). The SEM results revealed a modification mechanism of the treated concrete.
摘要：
A study was conducted to verify the validity of silane as an additive by monitoring the corrosion behavior of silane-enhanced mortar. Silane coupling agents were used in varying proportions, and the effect of the coupling agent content on mortar properties was studied. The integral silane mortar additive was (γ-glycidoxypropyl) methyldimethoxysilane (KH560). River sand with a fineness modulus of 2.43 was used as the fine aggregate. A water/cement ratio of 0.4 was used for preparing mortar mixtures incorporating no silane (the reference sample), and 1, 3, and 5% silane. Distilled water was used to prepare the mortars.<br/>
摘要：
Graphene oxide (GO) is increasingly used in various applications, and the implications of this nano-sized material entering the natural environment are of great interest. GO is highly soluble in water, and its accumulation in soil could significantly alter the physical and mechanical properties of the soil. In this laboratory study, we mixed GO with a soil (clayey sand, SC) to systematically study the engineering properties and microstructure of the modified soil. The experimental results reveal that the physical and mechanical properties and microstructure of clayey sand can be significantly changed by the addition of a minute quantity of GO. The liquid limit and plasticity index of the soil steadily increased (up to a GO concentration of 0.08 wt%), whereas the plastic limit did not change significantly. The addition of GO (up to 0.08 wt%) into the soil generally decreased the soil's void ratio under a given hydrostatic consolidation pressure, while increasing its undrained shear strength. Such remarkable modifications of soil by minute amounts of GO can be attributed to the extremely high specific surface area of GO and its stable dispersion in water.
摘要：
Rayleigh-Benard convection in liquids with nanoparticles is studied in the paper considering a two-phase model for nanoliquids with thermophysical properties determined from phenomenological laws and mixture theory. In the absence of nanoparticle-modified thermophysical properties as used in the paper, the problem is essentially binary liquid convection with Soret effect. The base liquids chosen for investigation are water, ethylene glycol, engine oil, and glycerine, and the nanoparticles chosen are copper, copper oxide, silver, alumina, and titania. Using data on these 20 nanoliquids, our theoretical model clearly explains advanced onset of convection in nanoliquids in comparison with that in the base liquid without nanoparticles. The paper sets to rest the tentativeness regarding the boundary condition to be chosen in the study of Rayleigh-Benard convection in nanoliquids. The effect of thermophoresis is to destabilize the system and so is the effect of other parameters arising due to nanoparticles. However, Brownian motion effect does not have a say on onset of convection. In the case of nonlinear theory, the five-mode Lorenz model is derived under the assumptions of Boussinesq approximation and small-scale convective motions, and using it enhancement of heat transport due to the presence of nanoparticles is clearly explained for steady-state motions. Subcritical motion is shown to be possible in all 20 nanoliquids.
摘要：
A microemulsion was successfully prepared via polycondensation of alkoxy silanes. Research into the control of the preparation and properties of the microemulsion was conducted. The structure and properties of the microemulsion were characterized by transmission electron microscopy (TEM) and photon correlation spectroscopy (PCS). The variation in the temperature, the methods, and the amount of catalyst and surfactant was studied in relation to the properties of the final microemulsion.
