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- MakaleYalnız künye2021Scopus SJRQ1A regional supplementary cementitious material for the cement industry: Pistachio shell ash
Tekin, İ.; Dirikolu, İ.; Gökçe, H.S.
The recycling of agricultural wastes in cementitious products has recently been a trendy approach for the sustainability goals of the world as it ensures economic and ecological advantages in addition to the safe disposal of these wastes. In this regard, the potentiality of a biomass ash obtained from the incineration of pistachio shell to serve as a supplementary cementitious material is documented in the present study. An increase of up to 30% in the amount of pistachio shell ash resulted in the proportional increase of both water requirement and setting time of the ordinary Portland cement by up to 54% and 300%, respectively. The incorporation of up to 20% pistachio shell ash into the cement yielded specimens of comparable or higher compressive strength values relatively varying between 98% and 117% at the 28 days and later curing ages. Beside the cementitious property, it was observed that a presence of graphitic structures in the pistachio shell ash remarkably improved the mechanical and the microstructural properties of cement mortars. In conclusion, at least 10% incorporation of this ash into the cement is highly recommended for the cement industry as it is beneficial in achieving the highest ultimate (400-day) compressive strength and promotes no loss on the early (2-day) compressive strength.
AtıfScopus41WoS38OpenAlex45
İncele - 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.
AtıfOpenAlex1
İncele - MakaleYalnız künye2018Scopus SJRQ2X-ray CT monitoring of macro void development in mortars exposed to sulfate attack
Tekin, Ilker; Birgul, Recep; Aruntas, Huseyin Y.
This study reports the results of nondestructive monitoring of macro void developments in mortars manufactured with both ordinary Portland cement and sulfate resistant cement. Two types of curing were utilized; tap water curing and another curing environment that contains 5% Na2(SO4) solution. Being the primary objective of this study, macro void developments of the mortar specimens were monitored by X-ray Medical Computerized Tomography. Compressive strength tests and water absorption tests were conducted on specimens that were kept in both curing environments for a duration of 560 days. Data analyses yielded consistent results among the three tests used in this experimental study. Macro void ratios of mortars decreased at the beginning of experiments for a certain period; afterwards, macro void ratios increased. The objective of this study was accomplished as anticipated since X-CT image analysis was able to nondestructively monitor macro void development process in cement mortars.
AtıfScopus6WoS6OpenAlex1İncele - MakaleYalnız künye2012Scopus SJRQ1Determination of the effect of volcanic pumice replacement on macro void development for blended cement mortars by computerized tomography
Tekin, Ilker; Birgul, Recep; Aruntas, Huseyin Yilmaz
In this study, the effect of volcanic pumice replacements with different ratios on the macro void development was observed using CT for a period of 100 days. The cured mortar specimens were imaged by X-ray CT on different days of the experiment. Utilizing Hounsfield Unit values as guides, void volumes and ratios were identified and measured by Matlab software. SEM images supported the X-ray CT results. It is shown that X-ray CT analysis is capable of assessing the development of macro voids in the mortar specimens.
AtıfScopus22WoS21OpenAlex20İncele