The performance of a cathodic protection system in reinforced concrete structure: Monitoring and Service Life Modelling

The use of cathodic protection in reinforced concrete is becoming increasingly common with such systems being installed on a number of structures throughout the United Kingdom and Ireland. However the prescribed design lives (or service life) of each cathodic protection system vary widely. The aim of this project was to assess the effectiveness of a sacrificial anode cathodic protection system and to predict its design life through a series of laboratory based experiments. The experimental plan involved casting a number of slabs which represented a common road bridge structure. The corrosion of the steel within the experimental slabs was then accelerated prior to installation of a cathodic protection system. During the experiment corrosion potential of the steel reinforcement was monitored using half-cell measurement. Additionally the current flow between the cathodic protection system and the steel reinforcement was recorded to assess the degree of protection. A combination of theoretical calculations and experimental results were then collated to determine the design life of this cathodic protection system. It can be concluded that this sacrificial anode based cathodic protection system was effective in halting the corrosion of steel reinforcement in the concrete slabs studied. Both the corrosion current and half-cell potentials indicated a change in passivity for the steel reinforcement once sacrificial anodes were introduced. The corrosion current was observed to be sensitive to the changes to the exposure environment. Based on the experimental variables studied the design life of this sacrificial anode can be taken as 26 to 30 years.

The Influence of Child Protection Orientation on Child Welfare Practice

This article reports the findings of the second part of a two-part research project examining the potential for social workers to make changes in their work with families and children. While social workers in the United Kingdom have been encouraged to shift from a child protection to a child welfare orientation in their practice, such changes have been hampered by professional and organisational concern to manage risk. The research explores the influence of a child protection orientation on practice in child welfare cases. The findings, from two file analyses and interviews with twenty-six social workers, indicate that such an influence is indeed apparent. This is evidenced in two ways; firstly patterns of practice in child welfare cases are similar to those in child protection cases. Secondly, while the majority of social workers express an attitudinal desire to move towards a child welfare orientation, they still prioritise the management of risk in their practice. It is argued that social workers need permission from their employing organisations to make changes in their practice. This, in turn, requires such organisations to state clear goals in line with a child welfare orientation and develop holistic strategies to achieve these.