Determination of Mix Composition of Concrete Containing Fly Ash Using Gamma Spectrometry

2012 ◽  
Vol 1488 ◽  
Author(s):  
Konstantin Kovler ◽  
Zakhar Prilutsky
Keyword(s):  
Fly Ash ◽  
Gamma Spectrometry ◽  
Natural Radionuclides ◽  
Supplementary Cementitious Materials ◽  
Gamma Ray Spectrometry ◽  
Hardened Concrete ◽  
Concrete Composition ◽  
Activity Concentrations ◽  
Concrete Mix

ABSTRACTThe information about concentrations of natural radionuclides in concrete mix and mineral raw materials used for concrete manufacture, supplementary cementitious materials (SCM) including, can be helpful for determination of concrete composition. The paper deals with the novel approach to determine concrete mix composition – using gamma-ray spectrometry.In order to determine concrete composition, the content of naturally occurring radioactive materials (NORM) was determined in cement, FA and aggregates. Concrete compositions of both fresh and hardened mixes were determined by solving an over-determined system of four algebraic equations. The over-determined system consists of three equations, which represent activity concentrations of 226Ra, 232Th and 40K in concrete mix as a function of activity concentrations of the same radionuclides in cement, fly ash and aggregates, and the fourth conditional equation representing a sum of volumetric concentrations of cement, fly ash, aggregates and water in concrete mix as 100%. An over-determined system of linear equations was solved by the method of Lagrange multipliers, which provides a strategy for finding the maxima and minima of a function subject to constraints.Gamma spectrometry was found very sensitive to the presence of FA in both fresh and hardened concrete, while 232Th activity concentration - well correlated with the FA content in the mixes. On the contrary, accurate determination of the rest of concrete composition was difficult.

scholarly journals New Approach for the Determination of Radiological Parameters on Hardened Cement Pastes with Coal Fly Ash

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 475
Author(s):  
Ana María Moreno de los Reyes ◽  
José Antonio Suárez-Navarro ◽  
Maria del Mar Alonso ◽  
Catalina Gascó ◽  
Isabel Sobrados ◽  
...  
Keyword(s):  
Fly Ash ◽  
Activity Concentration ◽  
Gamma Ray ◽  
Coal Fly Ash ◽  
Cementitious Materials ◽  
New Method ◽  
Supplementary Cementitious Materials ◽  
Hardened Cement ◽  
Cement Pastes ◽  
Activity Concentrations

Supplementary cementitious materials (SCMs) in industrial waste and by-products are routinely used to mitigate the adverse environmental effects of, and lower the energy consumption associated with, ordinary Portland cement (OPC) manufacture. Many such SCMs, such as type F coal fly ash (FA), are naturally occurring radioactive materials (NORMs). 226Ra, 232Th and 40K radionuclide activity concentration, information needed to determine what is known as the gamma-ray activity concentration index (ACI), is normally collected from ground cement samples. The present study aims to validate a new method for calculating the ACI from measurements made on unground 5 cm cubic specimens. Mechanical, mineralogical and radiological characterisation of 28-day OPC + FA pastes (bearing up to 30 wt % FA) were characterised to determine their mechanical, mineralogical and radiological properties. The activity concentrations found for 226Ra, 212Pb, 232Th and 40K in hardened, intact 5 cm cubic specimens were also statistically equal to the theoretically calculated values and to the same materials when ground to a powder. These findings consequently validated the new method. The possibility of determining the activity concentrations needed to establish the ACI for cement-based materials on unground samples introduces a new field of radiological research on actual cement, mortar and concrete materials.

scholarly journals Inter-comparison exercise utilizing x- and γ-ray spectrometry

2020 ◽  
Vol 27 ◽  
pp. 121
Author(s):  
Filothei K. Pappa ◽  
Christos Tsabaris ◽  
Dionisis Patiris ◽  
Georgios Eleftheriou ◽  
Effrossini G. Androulakaki ◽  
...  
Keyword(s):  
Gamma Ray ◽  
Natural Radionuclides ◽  
Atomic Spectrometry ◽  
Gamma Ray Spectrometry ◽  
Metal Concentrations ◽  
Activity Concentrations ◽  
Great Divergence ◽  
Set Up ◽  
Comparison Exercise ◽  
Good Agreement

Radionuclides are characterized by their nuclear and chemical behavior. Additionally, the geochemical characteristics of radionuclides result in their accumulation in the sediments via sorption processes. In this work the radionuclide activity concentrations obtained by gamma-ray spectrometry (HPGe detector) were converted to metal concentrations as described in [1]. The results were compared with the measured metal concentrations obtained by atomic spectrometry (X-ray fluorescence system-XRF). The samples originate from the coastal environment of two Greek areas, characterized by elevated values of natural radionuclides (e.g. 226Ra) and metals. The preliminary study revealed a good agreement among the concentrations of potassium calculated via activity concentrations of 40K and those of XRF measurement, while a great divergence was observed for the thorium case. These differences can be attributed to the low statistics, as well as to the calibration set-up of Th XRF measurement.

Determination of Natural Radioactivity and Radiological Hazard Associated with Sediments Sourced from Ogunpa River Channels, Ibadan, Nigeria

2021 ◽  
Author(s):  
N N Jibiri ◽  
S O Egwu ◽  
N E Adesiji
Keyword(s):  
Building Material ◽  
Natural Radionuclides ◽  
Water Channel ◽  
River Channels ◽  
Activity Concentrations ◽  
Soils And Sediments ◽  
Radium Equivalent ◽  
Radiological Safety ◽  
Radiological Health

Abstract The natural radionuclides content and radiological assessment of sediments of the Ogunpa waste-water channel were evaluated to ascertain the radiological safety of the sediments as a building material. The mean activity concentrations of 40K, 226Ra and 232Th in Bq kg−1 were found to be 171 ± 69, 11 ± 5 and 10 ± 4, respectively. The overall mean radium equivalent 29 ± 13 Bq kg−1 was <370 Bq kg−1 that can give the maximum recommended dose of 1 mSv to the general public. The activity concentrations of the radionuclides were all less than world average for soils and sediments. Thus, the use of the sediments from the Ogunpa water channel as building material is safe and would not pose any significant radiological health hazards.

Effect of Curing Temperature on Hardened Concrete Properties

2005 ◽  
Vol 1914 (1) ◽  
pp. 97-104 ◽  
Author(s):  
W. Micah Hale ◽  
Thomas D. Bush ◽  
Bruce W. Russell ◽  
Seamus F. Freyne
Keyword(s):  
Fly Ash ◽  
Cementitious Materials ◽  
Curing Temperature ◽  
Supplementary Cementitious Materials ◽  
Cold Weather ◽  
Strength Development ◽  
Hardened Concrete ◽  
Hardened Properties ◽  
Hot Weather ◽  
Materials Used

Often, concrete is not mixed or placed under ideal conditions. Particularly in the winter or the summer months, the temperature of fresh concrete is quite different from that of concrete mixed under laboratory conditions. This paper examines the influence of supplementary cementitious materials on the strength development (and other hardened properties) of concrete subjected to different curing regimens. The supplementary cementitious materials used in the research program were ground granulated blast furnace slag (GGBFS), fly ash, and a combination of both materials. The three curing regimens used were hot weather curing, standard curing, and cold weather curing. Under the conditions tested, the results show that the addition of GGBFS at a relatively low replacement rate can improve the hardened properties for each curing regimen. This improvement was noticeable not only at later ages but also at early ages. Mixtures that contained both materials (GGBFS and fly ash) performed as well as and, in most cases, better than mixtures that contained only portland cement in all curing regimens.

The Influence of W/C Ratio and Superplasticizer Type on Porosity of Concrete with Air-Entraining Cement with Fly Ash

2018 ◽  
Vol 279 ◽  
pp. 266-270
Author(s):  
Beata Łaźniewska-Piekarczyk
Keyword(s):  
Fly Ash ◽  
Fresh Concrete ◽  
Air Entrainment ◽  
Hardened Concrete ◽  
Research Results ◽  
Concrete Mix ◽  
European Standards ◽  
New Generation ◽  
Air Entrained Concrete

The research results of stability of air-entrainment of concrete acc. PN-EN 480-1 in case of innovate air-entraining multi-component cement CEM II/B-V is presented in the paper. The influence of PCE, naphthalene and phosphonamidite based superplasticizers and w/c ratio: 0.45, 0.50 and 0.55 on air-entrainment and consistency of fresh concrete mix was investigated. The research results indicated that with increasing w/c ratio the air-entrainment of concrete increases. Moreover, in case of an increase in the degree of liquidity of the air-entrained concrete made of participation of the innovative, air-entraining multi-component cement CEM II/B-V, first and new generation superplasticizers based on modified naphthalene, and then modified phosphonamidite should be used. PCE based superplasticizer cause the too high air-entrainment of concrete. The research results proved, that the porosity of hardened concrete meets the European standards for frost-resistant concrete.

Determination of Slag and Fly Ash Content in Hardened Concrete

1995 ◽  
Vol 17 (1) ◽  
pp. 55 ◽  
Author(s):  
RD Hooton ◽  
RD Hooton ◽  
CA Rogers
Keyword(s):  
Fly Ash ◽  
Ash Content ◽  
Hardened Concrete

Characterization of Canadian fly ashes and their relative performance in concrete

1987 ◽  
Vol 14 (5) ◽  
pp. 667-682 ◽  
Author(s):  
G. G. Carette ◽  
V. M. Malhotra
Keyword(s):  
Fly Ash ◽  
Setting Time ◽  
Air Entrainment ◽  
Relative Performance ◽  
Hardened Concrete ◽  
Freezing And Thawing ◽  
Fly Ashes ◽  
Wide Range ◽  
Pozzolanic Properties

Eleven Canadian fly ashes were characterized and evaluated for their relative performance in concrete. Characterization included the determination of mineralogical composition, chemical composition, physical characteristics, and pozzolanic properties. The relative performance of each fly ash in concrete was evaluated through determination of the following properties of fresh and hardened concrete: slump, air content, bleeding, setting time, strength, modulus of elasticity, drying shrinkage, creep, and freezing-and-thawing resistance.The results indicate a wide range of chemical, physical, and pozzolanic properties for the fly ashes investigated. In spite of this, all the fly ashes studied are shown to be suitable for use in concrete. They affect, however, the properties of fresh and hardened concrete in different ways, and this should be taken into account when proportioning concrete containing these fly ashes. Key words: fly ash, concrete, pozzolanic activity index, bleeding, setting time, air-entrainment, strength, creep, shrinkage, freezing and thawing.

scholarly journals Determination of the activity concentration levels of the artificial radionuclide137Cs in soil samples collected from Qatar using high-resolution gamma-ray spectrometry

2016 ◽  
Vol 44 ◽  
pp. 1660237
Author(s):  
Huda Al-Sulaiti ◽  
Tabassum Nasir ◽  
K. S. Al Mugren ◽  
N. Alkhomashi ◽  
N. Al-Dahan ◽  
...  
Keyword(s):  
High Resolution ◽  
Nuclear Power ◽  
Activity Concentration ◽  
Gamma Ray ◽  
Germanium Detector ◽  
Soil Samples ◽  
Gamma Ray Spectrometry ◽  
Activity Concentrations ◽  
High Resolution Gamma

The goal of this study was to establish the first baseline measurements for radioactivity concentration of the artificial radionuclide [Formula: see text]Cs in soil samples collected from the Qatarian peninsula. The work focused on the determination of the activity concentrations levels of man-made radiation in 129 soil samples collected across the landscape of the State of Qatar. All the samples were collected before the most recent accident in Japan, “the 2011 Fukushima Dai-ichi nuclear power plant accident”. The activity concentrations have been measured via high-resolution gamma-ray spectrometry using a hyper-pure germanium detector situated in a low-background environment with a copper inner-plated passive lead shield. A radiological map showing the activity concentrations of [Formula: see text]Cs is presented in this work. The concentration was[Formula: see text]found to range from 0.21 to 15.41 Bq/kg. The highest activity concentration of [Formula: see text]Cs was observed in sample no. 26 in North of Qatar. The mean value was found to be around 2.15 ± 0.27 Bq/kg. These values lie within the expected range relative to the countries in the region. It is expected that this contamination is mainly due to the Chernobyl accident on 26 April 1986, but this conclusion cannot be confirmed because of the lack of data before this accident.

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