Investigation of Gamma Radiation Shielding of Concrete Containing Blast Furnace Slag Waste via Experimental and Calculation Methods

2018 ◽  
Vol 765 ◽  
pp. 329-334 ◽  
Author(s):  
Pranpriya Phutthanet ◽  
Pithiwat Tiantong ◽  
Phongthorn Julphunthong ◽  
Panuwat Joyklad ◽  
Li Jie Wang ◽  
...  

This study aims to evaluate gamma-ray shielding characteristics of concrete produced from blast furnace slag. The chemical and physical properties of the aggregates including the chemical composition and specific gravity were investigated to evaluate their radiation shielding properties. The samples were prepared with a cement content of 400 kg/m3, a water to cement ratio of 0.4, and fine aggregate of 43% and coarse aggregate ratio of 57%. Blast furnace slag was replaced with sand at 25%, 50%, 75% and 100% by volume to improve the shielding properties. The compressive strengths at 3, 7 and 28 days and the unit weight of the prepared samples were determined. The linear attenuation coefficient was measured and calculated at photon energies of 0.662 MeV, 1.17 MeV and 1.33 MeV. The WinXCom program was employed to calculate the attenuation coefficient from the chemical composition of samples and the results were compared to the measured results. The study results suggest that the use of blast furnace slag is effectively in improving the compressive strength and shielding properties of concrete. The increase of blast furnace slag caused an increase in the linear attenuation from 0.190 cm-1 to 0.210 cm-1 at 0.662 MeV.

Author(s):  
Hitoshi Owada ◽  
Tomoko Ishii ◽  
Mayumi Takazawa ◽  
Hiroyasu Kato ◽  
Hiroyuki Sakamoto ◽  
...  

A “realistic alteration model” is needed for various cementitious materials. Hypothetical settings of mineral composition calculated based on the chemical composition of cement, such as Atkins’s model, have been used to estimate the alteration of cementitious material. However, model estimates for the concentration of certain elements such as Al and S in leachate have been different from experimental values. In a previous study, we created settings for a mineralogical alteration model by taking the initial chemical composition of cementitious materials from analysis results in experiments and applying their ratios to certain hydrated cement minerals, then added settings for secondary generated minerals in order to account for Ca leaching. This study of alteration estimates for ordinary portland cement (OPC) in groundwater showed that the change in Al and S concentrations in simulated leachate approached values for actual leachate[1]. In the present study, we develop an appropriate mineral alteration model for blended cementitious materials and conduct batch-type leaching experiments that use crushed samples of blast furnace slag cement (BFSC), silica cement (SC), and fly ash cement (FAC). The cement blends in these experiments used OPC blended with blast furnace slag of 70 wt.%, silica cement consisting of an amorphous silica fine powder of 20 wt.%, and fly ash of 30 wt.%. De-ionized water was used as the leaching solution. The solid-liquid ratios in the leaching tests were varied in order to simulate the alteration process of cement hydrates. The compositions of leachate and minerals obtained from leaching tests were compared with those obtained from models using hypothetical settings of mineral composition. We also consider an alteration model that corresponds to the diversity of these materials. As a result of applying the conventional OPC model to blended cementitious materials, the estimated Al concentration in the aqueous solution was significantly different from the measured concentration. We therefore propose an improved model that takes better account of Al behavior by using a more reliable initial mineral model for Al concentration in the solution.


Author(s):  
Paweena Jariyathitipong ◽  
Kazuyoshi Hosotani ◽  
Takashi Fujii ◽  
Toshiki Ayano

2010 ◽  
Vol 64 (1) ◽  
pp. 244-250 ◽  
Author(s):  
Shingo MIYAZAWA ◽  
Takashi YOKOMURO ◽  
Hiromi FUJIWARA ◽  
Kiyoshi KOIBUCHI

X-ray photoelectron spectrometry (X.p.s.) measures the kinetic energy of electrons photoejected from a solid surface by soft X-rays. The kinetic energy of the photoelectrons can be related to the binding energy that these electrons had originally in the solid. X.p.s. is a rather new technique for studying cements. It has been used recently in the surface analysis of C 3 S, C 2 S, C 3 A and blast-furnace slag grains during their hydration. Changes in chemical composition have been found as soon as the surface comes into contact with water, shown by a change in the shape, position an intensity of characteristic peaks like Ca 2p , Si 2p , O l8 and a reduction of characteristic ratios Ca/Si or Al/Si. A tentative interpretation of X.p.s. kinetic curves as a function of hydration time is presented.


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