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    Corrosion and Chloride Diffusivity of Reinforced Concrete Cracked under Sustained Flexure
    (TMMOB İnşaat Mühendisleri Odası, 2020) Özyurt, Nilüfer; Söylev, Tayfun Altuğ; Özturan, Turan; Pehlivan, Ahmet Onur; Niş, Anıl
    This research discusses the chloride diffusivity of concrete as well as corrosion performance of rebars in cracked and uncracked states. Prismatic concrete specimens with two water-tocement ratios, two concrete cover thicknesses with and without steel fibers were used. Threepoint flexural loading was applied to form cracks and cracks were sustained by a bolt system. Half-cell potential and corrosion rate measurements were carried out following wetting - drying cycles in chloride environment which were continued for 80 weeks. The positive effects of lower water-to-cement ratio and greater cover depth were found to be surpassed by existence of cracks in concrete.
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    Testing of Maturity Methods for Concrete Quality Cured Using Various Temperatures
    (İstanbul Gelişim Üniversitesi Yayınları / Istanbul Gelisim University Press, 2021) Pehlivan, Ahmet Onur; Yazgan, Ahmet Utku
    Maturity of concrete is a subject of utmost essence in all phases of a construction project that has to be dealt with care and accordingly important advantages may be gained with optimum predictions. In this study, concrete specimens at various strength classes were prepared to investigate on the effect of concrete class on two different maturity function given in literature. Procedures were handled in accordance with the prescriptions given in ASTM C 1074. Recommendations given in the same standard for standard cement type was discussed and convenience of two different maturity functions were analyzed. Important values obtained from mortar specimens tests were applied to maturity calculations of concrete mixtures and applicability of the methods were discussed. It is found that with the increasing concrete quality, for two extreme temperatures (8 and 25 ?C) in this study, important deviations in the results are observed. Results obtained from specimens cured at 36 ?C were found to be significantly higher than specimens cured at 8 ?C at higher maturity levels. Datum temperature and Q-values data obtained from mortar mixtures were applied to concrete specimens and it may be asserted that concrete specimens demonstrated good correlation with the findings of both maturity functions. Generally, it may be expressed that maturity functions behave well under normal temperatures however applicability at extreme temperatures should be limited.