Accounting for Coupled Deterioration Mechanisms for Durable Concrete Containing Mineral By-Products

Sustainability of concrete materials often focuses on the benefits of incorporating mineral byproducts as alternative binders, thus reducing the cement amount requirements while not compromising performance. Yet performance is typically addressed from one perspective controlling the deterioration such as damaged caused by frost action, carbonation or chloride ingress alone. In this 3-year project, normal strength concrete was tested in the laboratory and at field sites with combinations of freeze-thaw, carbonation and chloride exposure at various ages to evaluate the influence of multiple attack types. Durability models are improved to account for deterioration interactions rather than single attack types alone. This paper shares some of the key laboratory and field test findings for mixtures containing by-products. The results are being used to update durability prediction tools which improve service life models for sustainability indicators used in design of concrete structures. BACKGROUND When durability of concrete is evaluated, many types of exposure or attack may be considered to influence the structural performance. Yet tools for predicting the lifetime of concrete materials are typically based on one driving force of the deterioration, such as spalling due to de-icer salt with frost exposure or cracking caused by chloride ingress and subsequent reinforcement corrosion. Accelerated laboratory tests are used to test these individual deterioration mechanisms and correlate the results to real-time performance of structures. In reality, existing structures are subjected to numerous and sometimes simultaneous forms of deterioration in their relative environments. Thus laboratory simulations and deterioration predictions should take into account these multiple, interacted deterioration parameters when modelling service life. A 3-year project was started in Finland in 2008 to address this need of understanding combined deterioration attack on concrete. This industry-lead project is entitled “Effect of Interacted