Yazar "Şimşek O." seçeneğine göre listele

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    Determination of alkali-silica reaction effects of zeolitic tuff addition on the different aggregates
    (2010) Gökçe H.S.; Taban S.; Şimşek O.
    The aim of this study is to determine the alkali-silica reaction (ASR) related characteristics of crushed stones that are produced from rocks of perlite, andesite and limestone when zeolitic tuff (ZT) is used in the mortar mix as cement replacement in different ratios. Accelerated mortar bar experiments in accordance with ASTM C 1260 were carried out on crushed stone aggregate samples to determine the ASR. CEM I 42.5 R type cement was replaced by ZT material in the following ratios: 0, 10, 20, 30 and 40%; in order to investigate the effects of replacement on the ASR pertaining to the aggregate types, 45 mortar bar pieces were produced. The length change values of the samples were measured on the 3, 7, 14, 28, 42, 56 days according to the accelerated mortar bar method. Measured length changes for the control samples on 14th day were found to be 0.570% at the level of potentially harmful for perlite, 0.101% at the level of critic for andesite and 0.061% at the level of harmless for limestone. Length changes at the harmful levels were taken under control for perlite at 30 and 40%, for andesite at 20, 30 and 40% ZT replacement ratios. Length change values of all samples decrease as ZT replacement increases. As a result, ZT replacement is effective to suppress the ASR of reactive aggregates.
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    Research of pesimum reactive aggregate ratio of the perlite aggregate with different methods
    (2010) Gökçe H.S.; Şimşek O.
    In this study, it is purposed to determine of reactive aggregate ratio of the perlite aggregate for given up the highest length change. For this purpose, properties of relate to alkali-silica reaction (ASR) of the perlite aggregate determined with non-reactive limestone aggregate. For the determination of ASR, according to ASTM C 1260 accelerated mortar bar method, for microstructure; Scanning Electron Microscope (SEM) and Energy Dispersive X-ray (EDX) analysis were carried out on the samples which are perlite, limestone and used both of them. Mixtures were prepared by weight at 0, 10, 20, 30, 40, 50 and 100% ratios with usage of perlite aggregate that obtained from Ankara Çubuk region instead of limestone aggregate that obtained from Ankara Hasano?lan region. 21 pieces of mortar bars were produced for 7 different mixtures. The length change values of the samples were measured on the 3, 7, 10, 14, 21 and 28-day according to the accelerated mortar bar method. Morphology and chemical composition of highest length changed samples were determined with SEM and EDX. Increase of fracture density and Ca ratio was observed in parallel with the increase of length change. According to average of 14 days length change, 40% perlite aggregated samples underwent highest length change and these samples were determined as pesimum reactive aggregate ratio of the perlite aggregate.