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1
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Investigation of Heavy Concretes Produced with Heavy Artificial Aggregates

100%
Kılınçarslan Ş.
Acta Physica Polonica A
|
2015
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vol. 128
|
issue 2B
B-469-B-470
EN
For the adequate shielding of the radiological equipment using X and gamma rays, special materials with high attenuation properties are needed. This objective may be achieved by the use of concrete. Concrete engineers and technologists must take the role of aggregates more seriously, since there are increasing demands of modern concrete mixtures in terms of technological properties and greater economy. Heavyweight concrete contains aggregates that are natural or synthetic. In this study, metal industry waste products such as iron filings and rebar pieces were used to produce heavy concrete. Physical, mechanical and radiation shielding properties of the obtained concrete with barite, aggregates and artificial aggregates were studied. According to test results, the concrete produced with artificial aggregates can provide the desired physical properties. Radiation shielding coefficient was found to be proportional to the density of concrete.
2
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Investigation of the Effect of Selection of Construction Materials for Radiotherapy Centers

63%
Kılınçarslan Ş., Akyol B.
Acta Physica Polonica A
|
2016
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vol. 130
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issue 1
441-443
EN
Today, with the increasing use of various forms of radiation, all biological organisms are put at risk. Radiation science for medicine, agriculture, industry and military purposes has grown wide. To be protected from the harmful effects of radiation, attention should be paid to the time, distance and shielding rules. Shielding process varies according to the types of materials to be used. Turkey has the most abundant reserves of barite, which is a kind of heavy aggregate. Barite is experimentally used as a heavy concrete aggregate for radiation shielding purposes. In the present study, at first the shield thickness of the designed radiotherapy centre is computed according to the normal and heavyweight concretes. Then, the effect of type of material on the design of the radiotherapy centre is examined carrying out static and structural analyses.
3
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The Effects of Accelerating Admixture on the Mechanical Properties of Boric Acid Added Mortars

51%
Davraz M., Kılınçarslan Ş., Pehlivanoğlu E.
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vol. 125
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issue 2
263-267
EN
Use of boron compounds has not become widespread because of the hardening and the other related problems in cementitious composites. The boron compounds as an additive material can be used widely in the production of cement and concrete in case of the elimination of these negative conditions. Thus the control of workability and hydration process of fresh concrete and mortar, some technological properties such as fire resistance, the radiation impermeability of hardened concrete and mortars can be enhanced. In this study, the effects of accelerating admixtures to the mechanical properties of boric acid added mortars were investigated. In order to determine of these effects and the results obtained to compare with those of control mortars, prismatic mortar samples were prepared in accordance with TS 196-1. Boric acid was added to mortar samples by up to 1% from 0.25% by weight of cement. Boric acid was not added to control mortar samples. Portland cement, boron modified active belite cement and calcium aluminate cement as binding material were used in mortar samples. 2, 7, 28 day compressive strengths and 28 day flexural strengths of 315 prismatic samples which were prepared in accordance with the design of 35 different mixes were determined. Results of boric acid added mortar samples were compared with control samples produced by using Portland cement, BAB cement and CAC cement. 2, 7, and 28 day compressive/flexural strength of mortar samples which were added 1% boric acid was determined as 0/0, 12.8/2.90, 40/6 MPa, respectively. Other hand, 2, 7, and 28 day compressive/flexural strength of mortar samples which were added 1% boric acid and 2% sodium aluminate was determined as 14.2/3.07, 27.2/5.57, 34.2/5.97 MPa, respectively. As a result, the retarding effect of the boric acid in terms of early strength of concrete was suppressed using sodium aluminate.
4
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Mechanical Performances of Artificial Aggregated Lightweight Concrete

51%
Davraz M., Ceylan H., Kılınçarslan Ş.
Acta Physica Polonica A
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2015
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vol. 127
|
issue 4
1246-1250
EN
In this study, some physical and mechanical performances of artificial aggregated lightweight concretes were compared. Special empirical models were developed to estimate the elasticity modulus of lightweight aggregate concrete (LWAC). Five different natural aggregates and one artificial lightweight aggregate material were used throughout the research. Mixture proportions were kept as constant values in all concrete mixtures. All mixtures were cast into cubic, prismatic and cylindrical concrete standard moulds and they were cured at the same curing conditions. A series of physical and mechanical properties, such as density, compressive strength and elasticity modulus for LWAC were experimentally determined. According to the research findings a few empirical models were statistically developed for estimating the elasticity modulus and Poisson's ratio of LWAC and a new diagram practically to be used for estimating the Poisson's ratio of LWAC was also proposed.
5
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Cement Paste as a Radiation Shielding Material

45%
Akkurt İ., Günoğlu K., Başyiğit C., Kılınçarslan Ş., Akkaş A.
Acta Physica Polonica A
|
2013
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vol. 123
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issue 2
341-342
EN
Cement, mainly, natural limestone and clay mixture after being heated at high temperature is obtained by milling and it is defined as a hydraulic binder material. Especially, cement is used in production concrete. The photon attenuation coefficient (μ, cm^{-1}) for cement paste has been measured using gamma spectrometer containing NaI(Tl) detector and MCA at 835, 1173, and 1332 keV. Cement paste was prepared with types of Portland cement which is CEM I 52,5 R- and CEN reference sand has been used according to TS EN 196-1 standard. The mass attenuation coefficients have been calculated at photon energies of 1 keV to 100 GeV using XCOM and the obtained results were compared with the measurements at 835, 1173, and 1332 keV.
6
Content available remote

Determination of Some Heavyweight Aggregate Half Value Layer Thickness Used for Radiation Shielding

39%
Akkurt İ., Başyiğit C., Akkaş A., Kılınçarslan Ş., Mavi B., Günoğlu K.
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EN
A radiation dose above the maximum permissible limit is very dangerous for human being. In radiation shielding, absorbent materials' properties must be well known. Heavyweight concrete is the most widely used in the world for this aim. The aggregate component of concrete plays an important role in improving concrete properties and this is effect of shielding properties of concrete. The thickness of any given material where 50% of the incident energy has been attenuated is known as the half-value layer. The half-value layer is expressed in units of distance (mm or cm). Like the attenuation coefficient, it is photon energy dependent. Increase of the penetrating energy of a stream of photons will result in an increase in a material's half-value layer. In this study, half-value layer thickness of concrete containing limonite, siderite and barite at different ratios was investigated; for this purpose measurements have been obtained by a collimated beam of gamma ray from sources ^{60}Co. The total linear attenuation coefficient (μ), half-value layer thickness is evaluated in this study.
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