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Chloride attack severely impacts the performance of reinforced concrete. The total and free chloride ion concentration (CIC) of self-compacting concrete (SCC) prepared with three supplementary cementitious materials (SCM) – fly ash (FA), blast furnace slag (BS) and silica fume (SF) – were measured by accelerated salt immersion tests. The apparent chloride diffusion coefficient (CDC) at any exposure time and erosion depth were calculated using the Boltzmann–Matano method. The influence of the type and content of SCM, the water–binder ratio (W/B) and the type of salt solution on CIC and CDC were investigated. Both the introduction of SCM and the reduction of W/B effectively reduced the CIC. The SCM that most effectively reduced CIC was SF, followed by BS and then FA. Free CIC was reduced to a greater degree than total CIC in FA and BS concrete, but the opposite was true for SF concrete. The presence of calcium chloride in salt solution increased total CIC while reducing free CIC. Apparent free CDC dropped over exposure time and initially increased with erosion depth but eventually stabilised. A model of apparent free CDC considering time–depth dependency was created, which shows that time reduction factors of CDC is greater in SCC containing SCM than in control SCC. [ABSTRACT FROM AUTHOR]

A new bridge was built in Kalix, northern Sweden, to replace an existing prestressed concrete box‐girder bridge that had been in service for over 60 years. The old bridge had a total length of 283.6 m divided into five spans: 43.9 m, 47.0 m, 94.0 m, 47.0 m, and 43.9 m. It was constructed using the balanced cantilever method with segments having lengths of around 3.0 m. The need for replacement arose from recommendations extracted from an assessment of the old bridge's state and capacity. In addition to the construction of the new bridge, its replacement necessitated the creation and evaluation of demolition procedure for the existing bridge. This procedure had to be carefully designed to avoid damaging the new bridge and stability‐related issues but also to prevent debris from falling into the Kalix River, which is part of a Natura 2000 protected area. This paper discusses various issues considered while developing the demolition strategy, including the use of bed‐rock anchored tendons, intermediate support fixing at specific locations, and proper evaluation of position of the demolition equipment supported by the bridge, among others. The problem of disposing of the demolished material is also discussed. [ABSTRACT FROM AUTHOR]

As worldwide infrastructure is ageing, significant efforts have been paid to the development of strengthening techniques that will restore or increase the initial capacity of existing structures. Considering that it is expected that shear failure happens in a less ductile mode than that observed under bending actions, special attention has been devoted to shear strengthening methods. These methods included externally bonded fiber reinforced polymers (EB‐FRP), near‐surface mounted (NSM‐FRP) method, and the embedded trough‐section (ETS) technique, among others. In this paper, ETS method is used for the strengthening in shear of a reinforced concrete railway bridge located in Finland. The ETS method consists in the embedment of FRP or steel bars through predrilled holes into the concrete core. The bars are bonded to the concrete using adhesives. The paper includes a brief review of recent advances in the use of ETS and comparison with other available techniques, the description of the case study, instrumentation of the bars using fiber optic sensors (FOS) for strain monitoring, the procedure used for the installation of the bars in the field, and a preliminary analysis of the data collected. [ABSTRACT FROM AUTHOR]

Traditional visual inspections of existing infrastructure have limitations such as safety risks, limited accuracy for subsurface defects, and subjective assessments. Modern inspection techniques like terrestrial laser scanning, closerange photogrammetry (CRP), and infrared scanning offer faster and more accurate data collection, allowing for more informative and precise descriptions of objects, while minimizing traffic disturbances often associated with visual inspections. In this paper, CPR, a non‐destructive survey technique for reconstructing 3D shapes from 2D images, is used for the inspection of five bridges in Northern Sweden. The surveys were performed under different weather conditions, using different data acquisition equipment and personnel with different levels of experience. The acquired images were used to create 3D models of the bridges and to evaluate the evolution of damages over time. Results showed that although better models were created when using equipment with higher specifications, cheap gear such as GoPro or cellphones can also be used for the cases in which a lower level of detail is required. Furthermore, initial experience of the personnel does not seem to have high influence on the results. [ABSTRACT FROM AUTHOR]