PERFORMANCE BASED DURABILITY DESIGN

摘要

Performance requirements for (concrete) structures are usual with respect to structural safety and fire-resistance. They are also imposed for the service life of structures, such as 50 years for buildings and 75 years for bridges. However to meet these service life requirements mostly descriptive specifications are used which prescribe the constituent materials and put limitations on the mix design e.g. the water/cement ratio, cover thickness and curing conditions. Implicitly it is assumed that the performance requirements with respect to the service life of the structure are fulfilled. Descriptive requirements are valid within strict boundaries of the composition and application of the concrete. In a strongly changing concrete market in which the bandwidth of concrete performance is strongly increasing with a growing variety of additions, admixtures and aggregates these descriptive requirements are often not applicable. A performance-based approach is required for those new concrete compositions and applications. The paper presents respectively: definitions, the level on which requirements are imposed, what explicitly designing on durability means, tests methods to assess the performance progress and durability performance requirements already existing in various standards notably the European standard for concrete EN 206.