Durability design and service life modeling of concrete structures rely on environmental exposure classes based on the prevailing deterioration mechanisms. International standard environmental exposure classes, for example, those found in the fib Model Code 2010 and ISO 22965-1:2007 are predominantly based on European environmental conditions. Although these exposure classes are more suited to the prescriptive design for durability, they may also be adapted to performance-based design. For more complex design philosophies such as limit state design using partial factors, the generalizations of the standard exposure classes cannot be suitably employed and therefore a more rigorous characterization of the exposure environment is required. The standard exposure classes in the fib Model Code 2010 as well as various national codes from different regions of the world are critically reviewed, and their limitations highlighted. Based on the review, updates to the standard exposure classes for inclusion in the fib Model Code 2020 are proposed. This paper summarizes the work of TG8.8 WP3 (Commission 8: Durability, Task Group 8.8: Common approaches, Working Party 3: Exposure Zones) and represents the view of the Working Party members.

中文翻译：

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为耐久性设计和规范定义暴露等级的进展

混凝土结构的耐久性设计和使用寿命建模依赖于基于普遍劣化机制的环境暴露等级。国际标准环境暴露等级，例如fib模型代码 2010 和 ISO 22965-1:2007 中的等级主要基于欧洲环境条件。虽然这些暴露等级更适合耐久性的规定设计，但它们也可能适用于基于性能的设计。对于更复杂的设计理念，例如使用部分因子的极限状态设计，不能适当地采用标准暴露类别的概括，因此需要对暴露环境进行更严格的表征。fib 中的标准暴露等级标准规范 2010 以及来自世界不同地区的各种国家规范都经过严格审查，并强调了它们的局限性。根据审查，建议更新标准暴露类别以包含在fib模型代码 2020 中。本文总结了 TG8.8 WP3（委员会 8：耐久性，任务组 8.8：通用方法，工作组 3：暴露区）的工作，并代表了工作组成员的观点。