RESUMO
Cathodic protection (CP) is being increasingly used on reinforced concrete structures to protect steel reinforcing bars from corrosion in aggressive conditions. Due to the complexity of environmental conditions, the design specifications in national and international standards are still open to discussion to achieve both sufficient and efficient protection for reinforced concrete structures in engineering practices. This paper reports an experimental research to investigate the influence of chloride content on concrete resistivity, rebar corrosion rate and the performance of CP operation using different current densities. It aims to understand the correlation between the chloride content and concrete resistivity together with the CP current requirement, and to investigate the precision of the CP design criteria in standards.
RESUMO
Neutron diffraction data from in situ deuteration and dedeuteration of Li(3)N are presented under different pressure regimes, whereby reaction pathways differing from the widely reported stoichiometric pathway of Li(3)N + 2D(2)<--> Li(2)ND + LiD + D(2)<--> LiND(2) + 2LiD are observed. At sufficiently high pressures, where the deuterium chemical potential is comparable with the heat of amide formation, the reaction appears to be driven straight to the amide plus deuteride phase mixture. At lower pressures, a cubic phase exhibiting a concentration-dependent variation in lattice parameter is observed. In dedeuteration, two sets of reflections from cubic structures with distinct lattice parameters are observed, both of which exhibit a continual decrease in cell volume. The reaction pathways are discussed in terms of the compositional variation.