Sürdürülebilir Kalkınma Amaçları
Yayınlar
- MakaleAçık Erişim2020Optimising High Lime Fly Ash Content By Means of Silica Fume Incorporation to Control Alkali-Silica Reaction And Drying Shrinkage of Mortars
Gökçe, H. Suleyman; Hosseinnezhad, Hojjat; Üzüm, Onur; Hatungimana, Daniel; Ramyar, Kambiz
In this study, the effect of binary and ternary cementitious systems composed of portland cement, high-lime fly ash and silica fume on the compressive strength, alkali-silica reaction (ASTM C 1567) and drying shrinkage of mortar mixtures was researched. For this purpose, binary and ternary binders were prepared with partial replacement of cement with either fly ash (15wt% and 30wt%) or silica fume (5wt%) or both mineral admixtures (15wt+%5wt% and 30wt%+5wt%). An alkali reactive basalt aggregate was used in this study. It was found that partial replacement of cement with high-lime fly ash reduced the strength of mortar mixtures even up to 28-days. Besides, addition of 5% silica fume had not a significant effect on the early strength of fly ash-bearing mixtures. However, silica fume inclusion improved the 28-day strength of mixtures. In terms of alkali-silica reaction (ASR), the fly ash with lower lime content reduced the 14-day expansion more than that of fly ash with higher lime content. The opposite results were the case in 28-day ASR expansions. The ASR expansions of the fly ash-bearing mixtures were significantly reduced by the introduction of the additional 5% silica fume to these mixtures. However, silica fume incorporation remarkably increased the drying shrinkage values of the mixtures. Finally, fly ash with higher lime content was found to be more satisfactory in terms of compressive strength, alkali-silica reaction and drying shrinkage in the ternary binder system.
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İncele - MakaleYalnız künye2019Scopus SJRQ1Assessment of Alternative Segregation Test Methods for Self-Consolidating Heavyweight Concrete
Gökçe, H. Suleyman; Aksan, Umut; Andiç-Çakir, Ozge
This investigation is focused on the use of alternative segregation test methods on high-performance self-consolidating heavyweight concrete. Many segregation test methods have been developed by researchers up to now; however, the disadvantages of these methods, such as being time-consuming, the requirement of excessive labor, and the lack of precision, cannot ensure their worldwide prevalence. In the study, the segregation limitations stated in various test methods, that is, the column test, density variation method, and 3-compartment sieve test, were evaluated on self-consolidating heavyweight concrete produced with barite aggregate. For this purpose, in total, eight self-consolidating heavyweight concrete mixtures designed in two water/binder ratios were prepared by replacing viscosity modifier, silica fume, and fly ash with ordinary Portland cement in different amounts. The mixtures were constituted in satisfactory segregation grades, allowing researchers to evaluate the relationship between those methods. The segregation coefficient limits of the column test, density variation method, and 3-compartment sieve test are recommended as 7%, 1%, and 6.3% for the self-consolidating heavyweight concrete mixtures tested in the study.
AtıfWoS5OpenAlex7İncele - MakaleYalnız künye2010Effect of Alternative Expanded Perlite Using on Properties of Raw Perlite Aggregated Light-Weight Concrete
Gökçe, H. Suleyman; Simsek, Osman; Durmus, Gokhan; Demir, Ilhami
Perlite is a natural building materials contribute to global warming positive thanks to its isolation and lightness characteristics as concrete aggregate with usage of in construction sector. In research results, about %74 of world perlite reserves was determined to be in Turkey. It is thought that energy of fairly hard obtained will provide more efficient usage thanks to efficient usage of the natural reserves. Such approaches will provide to reduce of environment pollution in the usage of energy. In this study, with different characteristic usability of expanded perlite aggregate was researched in raw perlite aggregated light weight concrete. 7 different mixtures were prepared in volume at 10% ratio by using 3 different expanded perlite aggregate instead of raw perlite aggregate. With prepared light weight concrete mixtures 100x100x100 mm sized cube samples were produced. 28 days compressive strength, unit volume weight and water absorption ratio of these sample were researched. As a result, with suitable characteristic usage of expanded perlite aggregate was understood to be effective on the mechanical and physical properties of perlite aggregated light weight concrete.
AtıfWoS3İncele - MakaleYalnız künye2010Scopus SJRQ2RESEARCH OF PESIMUM REACTIVE AGGREGATE RATIO OF THE PERLITE AGGREGATE WITH DIFFERENT METHODS
Gökçe, H. Suleyman; Simsek, Osman
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 Cubuk region instead of limestone aggregate that obtained from Ankara Hasanoglan 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.
AtıfWoS3İncele - MakaleYalnız künye2010Scopus SJRQ2DETERMINATION OF ALKALI-SILICA REACTION EFFECTS OF ZEOLITIC TUFF ADDITION ON THE DIFFERENT AGGREGATES
Gökçe, H. Suleyman; Taban, Saniye; Simsek, Osman
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 14(th) 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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