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In the Hokuriku region, alkali-silica reaction (ASR) caused severe degradations in many concrete bridges. However, criteria for repair and replacement works of these structures are still unclear. For the development of damage evaluation procedure, it is necessary to investigate the load-carrying capacity of prestressed concrete (PC) girders affected by ASR-induced deterioration in actuality. This study constructed two full-size PC specimens from the high-early-strength Portland cement and reactive aggregates, and then exposed them to outdoor environmental conditions. One of them was specially mixed with a controlled amount of fly ash. After one and a half years of outdoor exposure, destructive loading tests were carried out to investigate the difference in loading capacity of the girders. From results of the long-term exposure and the tests, the flexural strength and the rigidity of the specimen with fly ash were not degraded while ASR was also effectively suppressed. In addition, cylindrical concrete cores were taken at different positions of both girders to analyze the relationship between mechanical properties of concrete such as compressive strength, static elastic modulus, and ultrasonic wave propagation speed. Results of the coring test showed that the mechanical properties of concrete cores varied according to their collecting positions and directions.

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Quinoline derivatives are important moieties in bioactive molecules and advanced materials. However, an efficient strategy to synthesize quinoline derivatives remains challenging. Herein, we describe an efficient and practical method for the synthesis of quinolines by Cu-catalyzed cyclization of 2-amino benzyl alcohol with ketones (or secondary alcohols) via an acceptorless dehydrogenation pathway. Interestingly, a range of highly functionalized quinolines is prepared in good yields using low catalyst loading under relatively mild conditions. Furthermore, density functional theory (DFT) calculations are carried out to investigate mechanistic insights for the acceptorless dehydrogenation pathway.

Structural responses have been used as inputs in the evaluation procedures of civil structures for years. Apart from the degradation of a structure itself, changes in the environmental conditions affect its characteristics. For adequate maintenance, it is necessary to quantify the environment-induced changes and discriminate them from the effects due to damage. This study investigates the variation in the vibration responses of prestressed concrete (PC) girders, which were deteriorated because of the alkali-silica reaction (ASR), concerning ambient temperature and humidity. Three PC girders were exposed to outdoor weather conditions outside the laboratory, one of which had a selected amount of fly ash in its mixture to mitigate the ASR. The girders were periodically vibration tested for one and a half years. It was found that when the temperature and humidity increased, the frequencies and damping ratios decreased in proportion. No apparent variation in the mode shapes could be identified. A finite element model was proposed for numerical verification, the results of which were in good agreement with the measured changes in the natural frequencies. Moreover, the different dynamic performances of the three specimens indicated that the fly ash significantly affected the vibrations of the PC girders under ASR deterioration.