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Heavy weight high performance concrete (HPC) can be used when particular properties,
such as high strength and good radiation shielding are required. Such concrete, using ilmenite and
hematite coarse aggregates can significantly have higher specific gravities than those of concrete made
with dolomite and air-cooled slag aggregates. Four different c...
Contexts in source publication
Context 1
... and mechanical properties of coarse aggregates and its fine portion carried out according to the limits specified by the ESS 1109 [13] and ASTM C637 [15] are given in Table 2. Results show that ilmenite has higher specific gravity and low- er water absorption than hematite, air-cooled slag and natural dolomite. ...
Context 2
... physical properties of the different concrete mixes are shown in Table 4. It can be observed that the differences in slump values are mainly attributed to the differences in water absorption of the used aggregates; these values are 0.7, 10.4, 0.1 and 1.4% for dolomite, hematite, ilmenite and air-cooled slag, respectively (Table 2). Therefore, hematite gives the lowest slump value; this is probably due to the high water content con- sumed by hematite aggregate to compensate its high absorp- tion, while, ilmenite gives the highest value. ...
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Citations
... The smelting process operates up to 2000 • C and evaporated and deposited mostly amorphous SF consists of over 90 % silica particles with less than 1 μm in size and spherical morphology [4,7]. SF improves the durability of hardened concrete through increased compressive strength, freeze-thaw resistance, corrosion and sulphate resistance, carbonation, and alkali-aggregate resistance [8][9][10][11]. SF contents were varied up to 30 % as cement substitutes but 10 % was evaluated as the optimal content [6,10,[12][13][14]. The positive influence of the SF substitute was explained in terms of the beneficial pozzolanic reaction between SF and calcium hydroxide with the formation of the secondary C-S-H gel phase and, as well as better packing density resulting in a dense interfacial zone [6,10,12]. ...
... SF improves the durability of hardened concrete through increased compressive strength, freeze-thaw resistance, corrosion and sulphate resistance, carbonation, and alkali-aggregate resistance [8][9][10][11]. SF contents were varied up to 30 % as cement substitutes but 10 % was evaluated as the optimal content [6,10,[12][13][14]. The positive influence of the SF substitute was explained in terms of the beneficial pozzolanic reaction between SF and calcium hydroxide with the formation of the secondary C-S-H gel phase and, as well as better packing density resulting in a dense interfacial zone [6,10,12]. ...
... SF contents were varied up to 30 % as cement substitutes but 10 % was evaluated as the optimal content [6,10,[12][13][14]. The positive influence of the SF substitute was explained in terms of the beneficial pozzolanic reaction between SF and calcium hydroxide with the formation of the secondary C-S-H gel phase and, as well as better packing density resulting in a dense interfacial zone [6,10,12]. ...
... In this case, the surface of the fillers should be well moistened with a water-cement solution for the cement paste to bond well with the surface of the filler. Fillers need to be hydrophilic [6,9]. This condition was achieved mainly by cleaning fillers from other organic-inorganic compounds. ...
... As a result, it causes the service life of hydrotechnical structures to decrease. According to the results of scientific research, it is justified that the optimal thickness of the cement paste between the small filler grains in the concrete is 0.040...0.1mm [6]. ...
In the article, the stages of formation of joint zones during the natural hardening of hydraulic concrete, the connections between cement stone and filler surface, and the influence of the mineralogical composition of fillers and external surface parameters on the structuring of cement stone in joint zones are studied by conducting laboratory tests. The development of high-performance technologies that accelerate the structuring of cement stone in the contact zones of hydraulic concrete fillers is considered urgent, and it is considered urgent to conduct scientific and practical research on the management of the spatial structuring mechanism arranged in the contact zones of fillers. The purpose of scientific and practical research is to study the possibilities of ensuring that hydraulic concrete strength reaches 70% within two days and to study the mechanisms affecting the kinetics of structuring in the contact zone.
... SF has specific gravity lower than that of cement. A high specific area with fine particle size creates higher water demand during mixture process, thus it has a negative impact on the workability leading to a higher amount of superplasticizer usage [70,74]. The particle size and shape of SF can be observed in Fig. 3 [75]. ...
The disposal of hazardous waste materials in landfills and open areas creates a severe impact on the environment. Silica Fume (SF), a by-product from the ferrosilicon and silicon industry, is generated in high quantities. Recent studies have highlighted the advantages of reusing SF to produce high-strength concrete (HSC) and ultra-high-performance concrete (UHPC) instead of discarding it. This paper herein reviews the current research on SF in concrete and discusses the physical and chemical properties, mechanical properties, durability, and microstructure. Depending on the concentration of the SF, flexural, tensile, and compressive strength was positively influenced. Also, SF improved the pore size to increase drying shrinkage through the pozzolanic reaction. A few studies showed the disadvantages of SF exhibiting the negative impact on workability and shrinkage of concrete. The influence of SF on cement hydration products should be analyzed from the microstructure perspective.
... The fast neutron removal cross-section of the air was ignored in this study, and neutrons travel 130 cm and reach the concrete wall without attenuation. The total microscopic cross-section values (σ)i of the concrete elements were collected at 2.45 MeV and then inserted into Equation (3) with the properties of the materials listed in Table 1 [54][55][56][57][58][59]. The fast neutron removal cross-section (∑Ri) values for each element of the materials were calculated, and the results are shown in Table 2. ...
... The fast neutron removal cross-section of the air was ignored in this study, and neutrons travel 130 cm and reach the concrete wall without attenuation. The total microscopic cross-section values (σ) i of the concrete elements were collected at 2.45 MeV and then inserted into Equation (3) with the properties of the materials listed in Table 1 [54][55][56][57][58][59]. The fast neutron removal cross-section (∑ Ri ) values for each element of the materials were calculated, and the results are shown in Table 2. ...
... Different photon interaction processes characterize the attenuation of X-or γ-rays inside the shielding materials. These processes include photoelectric absorption, Compton scattering, pair production in the nuclear field, and pair production in the electric field [41,55,[60][61][62][63][64]. Theoretically, the sum of these processes is represented by the total mass attenuation coefficient µ m given in Equation (5). ...
A radiation source based on the inertial electrostatic confinement fusion (IECF) system is being developed for multidisciplinary research applications. The radiation outputs from the IECF system are 2.45 MeV fast neutrons and the associated co-generated X-rays with an energy less than 3 MeV. A radiation shielding study has been performed on five types of concrete to define the most efficient material for the shielding design of the system. The proposed materials were ilmenite-magnetite concrete (IMC), ordinary concrete-1 (OC-1), barite-containing concrete (BC), ordinary concrete-2 (OC-2), and serpentine-containing concrete (SC). A numerical model was applied to determine the effective removal cross-section coefficients (∑Rt) for the fast neutrons and the total mass attenuation coefficients (µm), the half-value layer (HVL), the mean free path (MFP), the effective atomic number (Zeff), and effective electron density (Neff) for photons inside the materials. The model considered the radiation source energy and the material properties of the concrete types. The results revealed that the serpentine-containing concrete exhibited the highest ∑Rt with 12 cm of concrete thickness needed to attenuate an incident neutron flux to 1/100 of its initial value. In addition, the BC shows the highest µm with a 38 cm concrete thickness needed to attenuate the 3 MeV energy X-ray flux to 1/100 of its initial value. This study suggests that a 40 cm thickness of SC or BC adequately shields the radiation generated from an IECF system with a maximum particle production rate of up to 1 × 107 n/s.
... On the other hand, the production of high-strength concrete using tourmaline aggregate was (Gencel et al., 2010). Furthermore, the implementation of tourmaline aggregate in pavement design was demonstrated in many research works (Abo-El-Enein et al., 2014;Chyliński et al., 2020;Ghahfarokhi et al., 2014;Wang et al., 2014;Ding et al., 2017;Ye et al., 2019). ...
Gamma and neutron radiation causes severe effects on human health; many nuclear accidents led to radiation leakage affecting the environment and human health during the last century. Therefore, a great need for radiation shielding is now in demand. Concrete is the main constituent in any shielding design. This research investigates the mechanical properties of traditional concrete mixtures incorporating ilmenite or tourmaline aggregates. The crushing value of tested aggregates, along with the compressive and tensile behavior of concrete samples, was evaluated. Test results showed a general reduction in compressive and tensile strength of ilmenite concrete compared to conventional concrete by up to 18.2% and 27.5%, respectively. In contrast, tourmaline concrete achieved superior compressive and tensile strength than its conventional counterpart by up to 26.23% and 23.79%, respectively. The new concrete samples (Ilmenite and Tourmaline) are used in gamma and neutrons emission attenuation. Results show high gamma attenuation for both ilmenite (23-73%) and Tourmaline (32-79%). As for neutrons, the attenuation when using ilmenite was (9-37%) and for Tourmaline (13-42%).
... Heavy-density concrete made with air-cooled slag and fine aggregates of ilmenite can be used to enhance the shielding properties against gamma rays [99]. In the same study, they found that the crushed air-cooled slag can be used to develop concrete with highmechanical strength compared with corresponding concrete made with crushed hematite and ilmenite. ...
Concrete, an integral part of a nuclear power plant (NPP), experiences degradation during their operational lifetime of the plant. In this review, the major causes of concrete degradation are extensively discussed including mechanisms that are specific to NPPs. The damage mechanism could be chemical or physical. The major causes of chemical degradation include alkali–aggregate reactions, leaching, sulfate attack, bases and acids attack, and carbonation. Physical degradation is a consequence of both environmental and mechanical factors combined. These factors are mainly elevated temperature, radiation, abrasion and erosion, salt crystallization, freeze–thaw distortions, fatigue and vibration. Additionally, steel reinforcements, prestressing steels, liner plates, and structural steel also experience degradation. The prospective areas in the structural components of the NPP where the degradation could occur are mentioned and the effective solutions to the causes of degradation are highlighted. These solutions are designed to enhance the physical and chemical characteristics of concrete. Some of the major recommendations include addition of mineral substitutes, use of low water-to-cement ratio as well as low water-to-binder ratio, use of low alkali cement, use of special aggregates and fibers, use of corrosion inhibitors, use of cathodic protection, etc. The review concludes with an overview of present methods and possible recommendations used to enhance the quality of concrete towards preventing concrete degradation and increasing the lifetime of NPPs.
... At a percentage of 35.55-65.74% and 21-23.08% for Fe 2 O 3 and TiO 2 , respectively, ilmenite has a density of 4200-4240 kg/m 3 [76,79,80]. Hematite is also common in RSC research, but it is often reported to have a lower density than that of barite and magnetite. ...
... Fe 2 O 3 and 21-23.08% TiO 2 with a specific gravity of 4.2 [79,80]. This resulted in an attenuation coefficient percentage of 9.81%, which is higher than that of barite RSC at 9.73% [80]. ...
Nuclear energy offers a wide range of applications, which include power generation, X-ray imaging, and non-destructive tests, in many economic sectors. However, such applications come with the risk of harmful radiation, thereby requiring shielding to prevent harmful effects on the surrounding environment and users. Concrete has long been used as part of structures in nuclear power plants, X-ray imaging rooms, and radioactive storage. The direction of recent research is headed toward concrete’s ability in attenuating harmful energy radiated from nuclear sources through various alterations to its composition. Radiation shielding concrete (RSC) is a composite-based concrete that was developed in the last few years with heavy natural aggregates such as magnetite or barites. RSC is deemed a superior alternative to many types of traditional normal concrete in terms of shielding against the harmful radiation, and being economical and moldable. Given the merits of RSCs, this article presents a comprehensive review on the subject, considering the classifications, alternative materials, design additives, and type of heavy aggregates used. This literature review also provides critical reviews on RSC performance in terms of radiation shielding characteristics, mechanical strength, and durability. In addition, this work extensively reviews the trends of development research toward a broad understanding of the application possibilities of RSC as an advanced concrete product for producing a robust and green concrete composite for the construction of radiation shielding facilities as a better solution for protection from sources of radiation. Furthermore, this critical review provides a view of the progress made on RSCs and proposes avenues for future research on this hotspot research topic.
... A number of materials has been explored for shielding of nuclear radiation such as iron, lead, polyethylene, graphite, and concrete [9][10][11][12][13][14][15][16][17]. Concrete has been widely used in the construction of nuclear facilities primarily due to its versatility, structural strength, and ability to shield nuclear radiation [18]. Concrete is strong, having a reasonable shielding capacity, and, more importantly, economically viable material for the construction of radiation shielding structures in nuclear power plants, healthcare facilities involving radiology and particle accelerators, etc. ...
Concrete is an economical and efficient material for attenuating radiation. The potential of concrete in attenuating radiation is attributed to its density, which in turn depends on the mix design of concrete. This paper presents the findings of a study conducted to evaluate the radiation attenuation with varying water-cement ratio (w/c), thickness, density, and compressive strength of concrete. Three different types of concrete, i.e., normal concrete, barite, and magnetite containing concrete, were prepared to investigate this study. The radiation attenuation was calculated by studying the dose absorbed by the concrete and the linear attenuation coefficient. Additionally, artificial neural network (ANN) and gene expression programming (GEP) models were developed for predicting the radiation shielding capacity of concrete. A correlation coefficient (R), mean absolute error (MAE), and root mean square error (RMSE) were calculated as 0.999, 1.474 mGy, 2.154 mGy and 0.994, 5.07 mGy, 5.772 mGy for the training and validation sets of the ANN model, respectively. Similarly, for the GEP model, these values were recorded as 0.981, 13.17 mGy, and 20.20 mGy for the training set, whereas the validation data yielded R = 0.985, MAE = 12.2 mGy, and RMSE = 14.96 mGy. The statistical evaluation reflects that the developed models manifested close agreement between experimental and
predicted results. In comparison, the ANN model surpassed the accuracy of the GEP models, yielding the highest R and the lowest MAE and RMSE. The parametric and sensitivity analysis revealed the thickness and density of concrete as the most influential parameters in contributing towards radiation shielding. The mathematical equation derived from the GEP models signifies its importance such that the equation can be easily used for future prediction of radiation shielding of high-density concrete
... Experimental and analytical programs were developed to study the effects of cementing content and aggregates on the radiation shielding concrete (Kaplan 1989;Abo-El-Enein et al., 2014;Ouda 2015;El-Samrah et al., 2018a;Masoud et al., 2020). Accordingly, eight concrete mixes with varying density and composition were designed using the absolute volume method (ACI 1996) to meet a target slump of 100 ± 15 mm without any signs of segregation and bleeding, and a minimum compressive strength of 45 MPa. ...
Radiation shielding properties of 8 concrete mixes were studied in detail. The concrete mixes included 4 coarse aggregate types; dolomite, barite, ilmenite, and celestite, and 2 cementing material content. Important parameters accounted for in this study include: Mass attenuation coefficient that was calculated using WinXCom program then linear attenuation coefficient, half value layer, tenth value layer, and mean free path were deduced; Effective atomic number was calculated using Auto-Zeff software; Exposure build-up factor was calculated using the Geometric Progression approximation method up to 40 mean free path using Phy-X/PSD Software; Fast neutrons macroscopic effective removal cross-section and thermal neutron macroscopic absorption cross-section were calculated using MRCsC and JANIS-4 programs, respectively. Subsequently, the mixes were assessed for use in a dry storage cask using OpenMC code. The results showed that concrete mixes containing barite and celestite were the best in attenuating gamma rays emitted in narrow and broad beam situations.
... gr/cm 3 , hematite is 4.9-5.3 gr/cm 3, steel shot parts are 6.2-7.8 gr/cm 3 [34,35], and according to the above research, it is suggested that metal waste materials can be used as heavyweight fillers for special concrete. ...
... Concrete with metal fillers has increased thermal resistance, better thermal conductivity, and lower shrinkage. Meanwhile, it is difficult to eliminate the shrinkage completely and prevent the appearance of cracks on the border between cement and metal fillers [3,5,12,34,36,37]. ...
... However, despite the high density of samples, the capillary water absorption coefficient of PAS, PAMK, and PASMK samples were 1.14, 0.99, and 0.97 g/m 2 ·min, respectively. According to [3,34], more than the cement fineness of the pozzolanic microsilica and metakaolin additives, it is the powder that promotes filling the voids and a dense microstructure, and improves resistance to permeability in capillary [80,81]. ...
As the construction of hydrotechnical and energy facilities grows worldwide, so does the need for special heavyweight concrete. This study presents the analysis of the influence of waste-metal particle filler (WMP) on Portland cement (PC) paste and mortars with pozzolanic (microsilica and metakaolin) additives in terms of the hydration process, structure development, and physical–mechanical properties during 28 days of hardening. Results have shown that waste-metal particle fillers prolong the course of PC hydration. The addition of pozzolanic additives by 37% increased the total heat value and the ultrasound propagation velocity (UPV) in WMP-containing paste by 16%; however, in the paste with only WMP, the UPV is 4% lower than in the WMP-free paste. The density of waste-metal particle fillers in the free mortar was about two times lower than waste-metal particle fillers containing mortar. Due to the lower water absorption, the compressive strength of WMP-free mortar after 28 days of hardening achieved 42.1 MPa, which is about 14% higher than in mortar with waste-metal particle filler. The addition of pozzolanic additives decreased water absorption and increased the compressive strength of waste-metal particle filler containing mortar by 22%, compared to pozzolanic additive-free waste-metal particle fillers containing mortar. The pozzolanic additives facilitated a less porous matrix and improved the contact zone between the cement matrix and waste-metal particle fillers. The results of the study showed that pozzolanic additives can solve difficulties in local waste-metal particle fillers application in heavyweight concrete. The successful development of heavyweight concrete with waste-metal particle fillers and pozzolanic additives can significantly expand the possibility of creating special concrete using different local waste. The heavyweight concrete developed by using waste-metal particle fillers is suitable for being used in load balancing and in hydrotechnical foundations.
