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This study assessed the robustness of the chloride conductivity test with respect to the effect of concrete quality on its sensitivity to selected test parameters. Experiments were carried out to assess the sensitivity of the test to changes in the following parameters: (i) test duration (10, 40 and 120 s), (ii) concentration of the NaCl solution (3M and 5M), and (iii) variation of capillary voltage (7, 10 and 15 V). Concrete test specimens were made using three w/b ratios (0.40, 0.50 and 0.60) and three binder types (CEM I 52.5N (PC – Portland cement), 70/30 PC/FA (FA – fly ash) and 50/50 PC/GGCS (GGCS – ground granulated Corex slag)). One parameter was varied at a time. The results show that concretes with high chloride conductivity index (CCI) values (>∼0.8 mS/cm) are generally sensitive to changes in concentration of NaCl solution, capillary voltage across the test specimen, and test duration. For such concretes, the CCI increases with increase in capillary voltage, CCI decreases with decrease in salt concentration while the effect of a longer testing duration on CCI appears to be random. Even though it is not stipulated in the test standard, this study recommends that the test duration (i.e. the duration the capillary voltage is passed across the specimen once the electrical circuit of the test set-up is closed) is limited to <10 s. [ABSTRACT FROM AUTHOR]

• Ambient–cured FA-GPCC gave strong long-term strength gains of 60–90%. • Ambient–cured FA-GPCC exhibited good durability and pore quality characteristics. • Strong correlation exists between OPI and WSI values. • CCI test indicated potential interferences by pore ion fluxes. • Research is needed to assess whether the CCI method is suitable for testing FA-GPCC. While the geopolymer binder system is considered the foremost eco – friendly alternative to conventional Portland cement, its long – term performance has not yet been fully established. This study evaluated the long – term strength development and durability performance responses of fly ash (FA) – based geopolymer concrete mixtures activated using combined sodium silicate and sodium hydroxide solutions mixed at a varied ratio of the former to the latter, ranging from 0.72 to 4.89. The foregoing investigation was done focusing on effects of physico – chemical parameters comprising SiO 2 /FA, Na 2 O/FA and H 2 O/FA ratios. Concrete samples were cast then ambient – cured for one year, or oven – cured at 60 °C for 24 h followed by ambient – curing until testing. Various tests were done at 28 days or one year, including compressive strength, durability indexes, water absorption and volume of permeable pores. The durability indexes measured were water sorptivity, oxygen permeability and chloride conductivity. It was found that ambient – cured geopolymer concretes exhibited strong long – term strength gains of 60 to 90%, normal pore structure characteristics and good durability quality. However, the chloride conductivity test seemed to display erratic outputs, possibly due to ion fluxes, hence further research is needed to evaluate the method's suitability for testing geopolymer concretes. [ABSTRACT FROM AUTHOR]

Abstract: Three types of chloride‐conducting membranes based on polyvinyl chloride, commercial gelatin, and polyvinyldifluoride‐hexafluoropolymer are introduced in this report. The polymers are mixed with chloride‐containing salts, such as tetrabutylammonium chloride, and cast to form membranes. We studied the structural properties, thermal stability, and electrochemical response of the membranes to understand chloride migration and transport. Finally, the membranes are tested in a prototype solid‐state chloride‐ion battery setup. The feasibility of the membranes for their potential use in anion batteries is discussed. [ABSTRACT FROM AUTHOR]

Abstract: Three ground granulated slags (FeMn arc-furnace (GGAS), Corex (GGCS) and blastfurnace (GGBS) slags) of varying chemical composition, and from different sources were used to make concretes using two w/b ratios (0.40 and 0.60) and three slag replacement levels (20%, 35% and 50%). The effect of chemical composition and replacement level of slags on the chloride penetration resistance of the concretes was assessed using the chloride conductivity test. The results showed that the chloride penetration resistance of concrete increases with decreasing w/b ratio and increasing slag replacement level. In the GGAS concretes, despite having relatively low SiO2 and high MgO content, its significantly high Mn2O3 and low Al2O3 content was found to have a negative effect on the chloride penetration resistance of the concrete. The significantly high chloride penetration resistance of GGCS concretes was partly attributed to both its high CaO content and particle fineness. Only GGCS concretes showed a trend of increasing chloride penetration resistance with increased particle fineness; GGBS and GGAS concretes did not show any trend between particle fineness and chloride penetration resistance. The slag activity index was found to be a better indicator of chloride penetration resistance in concrete than the slag hydraulic index. [Copyright &y& Elsevier]

The ionic conductive properties were studied of epithelia of collecting duct principal cells which had been grown in primary tissue culture from renal cortex/capsule explants. When pretreated with aldosterone (10 mol/l) and bathed on either surface with isotonic HCO-free Ringer's solution, the transepithelial voltage, V, varied between −21 and −72 mV (apical surface negative) while the transepithelial resistance, R, ranged from 0.4 to 1.5 kΩcm. By 10:1 step-changes in Na concentration the apical cell membrane was shown to have a high conductivity for sodium, inhibitable by amiloride, 10 mol/l. However, contrary to observations in natural collecting duct under control conditions, amiloride never reversed the polarity of V even at 10 mol/l. Both the apical and the basolateral cell membranes were conductive for potassium and both conductivities were inhibitable by Ba (5 mmol/l). 10:1 reduction of apical Cl concentration strongly hyperpolarized V with a monophasic time course suggesting the presence of a paracellular shunt conductance for Cl. In addition there may be a small Cl conductance present in the apical cell membrane since apical application of the chloride channel blocker 5-nitro-2-(3-phenylpropylamino)-benzoic acid (NPPAB) at 10 mol/l produced a minute but significant hyperpolarization. On the other hand, 10:1 reduction of basolateral Cl concentration caused a biphasic change in V (initial depolarization, followed by repolarization) which indicates the presence of a large Cl conductance in the basolateral cell membrane. The latter was not inhibitable by 10 mol/l NPPAB. Higher concentrations of this and of an other Cl channel blocker produced non-specific effects. In conclusion, our studies of a pure principal cell epithelium confirm findings described for the intact cortical collecting duct and add new information concerning chloride conductivity and related blocking agents. [ABSTRACT FROM AUTHOR]