Concrete infrastructure degrades over time, not only a result of aging, but can also due to the inadequate design of concrete’s resistance to the ingress of moisture and aggressive ions. These are precursors for most forms of chemical attack and/or degradation of its physical microstructure. Although degradation due to freeze-thaw cycles, carbonation, corrosion, sulfate attack, etc. and the corresponding mechanisms have been studied for decades, the design of the durable structural concrete remains suboptimal. This is partly due to our inability to translate the kinetics of degradation reactions, rates of damage, symptoms of damage on small-scale (e.g. 100x200 mm cylinders or 75x75x300 mm prisms), unreinforced, unrestrained, mechanically unloaded specimens to large-scale, real life, structural elements that are reinforced (or prestressed), subjected to restraint, and mechanically loaded in tension or compression. There is a strong need for research to relate the performance of materials tested in the laboratory to the performance of structures in the field so that existing and new concrete structures are safe, sustainable and fulfill their estimated design life.
The overall scope of the presentation entails an overview of some specific aspects of an experimental study, with the objectives to: (i) identify key limitations in single-mechanism testing approaches; (iii) propose a series of parallel or in-sequence laboratory testing approaches; (iii) identify the parameters sensitive to coupled exposure; and (iv) recommend some potential paths forward related to linking accelerated laboratory testing pertaining to conditioning and sequencing, that encourage pessimum (worst case) behavior which will be applied and used to advance the understanding of coupled degradation mechanisms on concrete performance.