HIGH RESISTIVITY CONCRETE AND FRP BARS IN HIGH VOLTAGE APPLICATIONS

The addition of a combination of mineral admixtures and polymers, offer the potential to increase the electrical resistivity of concrete used in the construction of reinforced concrete structures without unduly compromising the material properties. This in itself may not provide the solution to the potentially hazardous situations arising during fault conditions in the vicinity of high voltage systems, but may aid in the overall mitigation of the problem when combined with other measures such as the use of FRP reinforcing and separate earthing systems. Although FRP bars provide potential benefits, their use in concrete construction in New Zealand has been limited. This may be due partly to FRP bars being considered new and unproven technology, and the design parameters may not yet by fully appreciated. Clearly, there are some questions regarding the long-term durability of GFRP bars incorporating E glass fibres. The bond-slip behaviour of FRP reinforcing bars is different to that of steel and although deterioration of the bars in concrete was not noted after one year, it is thought that bond performance may reduce with time. (A)