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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.
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İncele - MakaleAçık Erişim2020Scopus SJRQ1Physical and mechanical properties of cement containing regional hazelnut shell ash wastes
Baran, Y.; Gökçe, H. S.; Durmaz, M.
Turkey is ranked in the first place with two-thirds of the world hazelnut production. As the amount of shell obtained from shelled-hazelnut is almost equal to that of hazelnut by weight, the shell is a regionally important waste. The biomass is consumed as a fuel in some homes, workplaces, and public buildings with the help of specific caldrons. In the study, the use of ash was researched in the production of blended cement. For this purpose, blended cement mixtures containing hazelnut shell ash at the ratios of 0, 5, 10, 15, 20, 25 and 30% by weight of CEM I 42.5R ordinary Portland cement were prepared. The binary cementitious systems were assessed in terms of chemical, physical and mechanical properties. Hazelnut shell ash introduction increased the water demand up to 59% for standard consistency and reduced setting time up to 96% according to the ordinary Portland cement. Compressive strength results were remarkably reduced by an increase in the amount of ash. With over 5% of hazelnut shell ash introduction, the 28-d compressive strength value was found unsatisfactory (<42.5 MPa). The insufficient total amount of SiO2+Fe2O3+Al2O3 reduced the usage amount of the biomass ash in cementitious products due to having no pozzolanic characteristic. Hazelnut shell ash can be used as an alkaline set accelerator in concrete products as it is not steel-reinforced due to its high chlorine ion content. (C) 2020 Elsevier Ltd. All rights reserved.
AtıfWoS35OpenAlex41İncele - MakaleAçık Erişim2018Investigation of Superplasticiser Effect on Blended Cements Replaced By Bottom Ash
Tekin, Ilker; Tekin, Duygu
In the study, the main aim was determined conformity between blended cements and superplasticizer (SP) with fineness of mineral additives. Within this scope, compressive strength test and flow table test were performed on the cement mortars and standard consistency, setting times and soundness tests were performed on cement pastes which prepared with blended cements. In the experimental studies, bottom ash from Yatagan thermal power plant which was used after grinded size from 2 mm to 120 Am and 60 Am sizes was replaced with CEM I 42.5R type cement by weight 0%, 10%, 20% and 30%. Moreover superplasticizer additives which contained poly naphthalene sulfonate (PNS) from different companies were tried in blended cements According to the results, fineness of mineral additives increased the compressive strength of the mortars and accelerated setting times. PNS based SP's affects fresh paste behaviors such as reducing initial setting times and retarding finish setting times Another result is that company differences in PNS based chemical additives is significant parameter with cement conformity and this parameter makes up significant effects on fresh cement paste.
- MakaleAçık Erişim2018Effect of the polynaphtalene sulfonate based superplasticizer on mechanical and physical properties of blended cement replaced with Bayburt Stone at different fineness
Tekin, Ilker; Tekin, Duygu
In this study, grinded Bayburt Stone has pozzolanic property with 45 mu m and 125 mu m fineness was replaced with PC 42.5R (CEM-I) type cement at ratio of 0%, 10%, 20%, and 30% by weight. The aim of this study was made up in two phase, one of them was to investigate the effects of Bayburt Stone waste contain zeolite with different fineness on physical and mechanical properties of composite cements and the other one was to investigate behavior of same superplasticizer belong to two different company. Standard consistency, setting time and volume expansion tests are performed on the cement pastes and compression strength and flow tests are performed on the cement mortars. Mortar specimens are kept in standard curing for 28 days, than compressive strength test are performed at the ages of 2, 7 and 28 days. As a result, changes in specific surface area depending on the particle size distribution of mineral additives makes significant different on the physical, mechanical and rheological properties of cement mortars. In this study, it was determined that same type of superplasticizers which had different companies could be used in blended cement replaced with Bayburt stone.
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İncele - 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