In order to minimise the impact on the natural environment, the move from prescriptive to performance-based specifications for concrete materials and construction has become a critical issue in highway bridge design and construction. The Ontario Ministry of Transportation (MTO) has been moving away from prescriptive specifications since the mid 1980's starting with introduction of end-result based specifications for compressive strength. Today, MTO uses payment adjustment formulas for quality indicators measured on hardened concrete that include: compressive strength, air void system parameters and, for high performance concrete, rapid chloride permeability. However, the move to true performance-based specifications is impeded by the limited range of test methods available today and by the lack of verifiable links between test results obtained at the time of construction and the actual service life of the concrete structure. The paper describes attempts to evaluate, under realistic field conditions, the applicability of existing non-destructive test methods such as permeability to water, air penetrability, and electrical resistivity. For the covering abstract of this conference see ITRD number E216597.
Abstract