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• ASR expansion was suppressed and transferred to free or low stress directions. • Stress reduces the degradation of the modulus of elasticity. • ASR did not affect the peak shear strength of the low aspect ratio shear walls. • The Disturbed Stress Field Model provides a viable platform for implementing ASR constitutive models. Concrete nuclear structures have been identified as suffering from alkali aggregate reaction (AAR) in both Canada and the United States. Although much research effort has been directed toward understanding its effect on reinforced concrete structures, unresolved issues still remain. Among them are the effect of multiaxial stress states, commonly developed in nuclear structures, on the response of AAR-affected concrete; also of concern is the possible invalidity of conventional methods of analysis for structural assessment due to the induced anisotropy in the mechanical properties of concrete. The Canadian Nuclear Safety Commission initiated and funded an extensive study aimed to reveal the implications of concrete deterioration due to AAR on structural integrity, which included material and structural testing and modeling. This paper presents an overview of the entire research program and discusses the key results. [ABSTRACT FROM AUTHOR]

• Sheltered natural carbonation can be similar between different climates. • Huge impact of curing on natural carbonation for very early age (i.e. 1 day) • Impact of curing is negligible for advanced curing age, regardless of cement type. • Strong impact of precipitation on natural carbonation. • The higher the number of rainy days, the lower the carbonation speed. This paper describes a unique international inter-laboratory study on the carbonation resistance of concrete prepared with different supplementary cementing materials. Concrete specimens – from 45 different concrete mixtures – prepared centrally in Lafarge Centre de Recherche (France) were shipped in a sealed condition to 4 other academia research laboratories (located in USA, Canada, India and China). The specimens were exposed to the ambient environments and atmospheric CO2 concentrations in the five locations, including Lafarge Centre de Recherche in France, in both sheltered and unsheltered condition for a period of 5 years. Measurements of carbonation depth were performed at periodic intervals, and the data was analyzed to assess the influence of climatic conditions on the resistance to carbonation. The results indicate that the general trend of carbonation is not much different irrespective of the macroclimate. Further, the number of rainy days seems to have a more significant influence on the progress of carbonation than the total rainfall in the region. [ABSTRACT FROM AUTHOR]

Abstract: Many transportation authorities in the United States and Canada require condition assessments of concrete bridge decks and roadways as part of scheduled rehabilitation and maintenance programs. Nondestructive test (NDT) methods and laboratory studies are commonly used by engineering consultants to perform these evaluations. Amongst typical NDT methods, ground-penetrating radar (GPR) is one of the best suited to accomplish this task. Unfortunately, reported test results are oftentimes ambiguous, due to the current numerical analysis approach to evaluate the data. This paper describes some of the shortcomings of numerical analysis of GPR profiles and it introduces an alternative method developed by the authors. Several examples of actual field investigations are described, where the computer-assisted visual interpretation of GPR profiles was used to validate and eventually improve this new analysis approach. The authors’ project experiences on several structures indicate that mapping defects by visual identification of corrosion-induced anomalies in concrete is a much more accurate way of mapping defects. The results obtained from the field applications suggest that use of the computer-assisted visual interpretation of GPR data is an efficient and reliable approach that can be used by experienced GPR analysts. [Copyright &y& Elsevier]