Heavyweight Concrete Research Articles

Impact of natural aggregates and some industrial wastes on radiation shielding properties of heavyweight concrete: Experimental and theoretical study

The methodology to produce five concrete specimens with high density has been conducted, incorporating natural aggregates such as sand and basalt as well as commercial aggregates like lead and copper. These specimens have been designed for use in structural and radiological shielding purposes. The five specimens exhibit exceptional mechanical features, characterized by superior performance and remarkable stability. The specimen labeled heavyweight concrete with 36% Pb (HWC36Pb) has been found to have a compressive strength of 28 MPa and a tensile strength of 2.76 MPa. Furthermore, the current work specimens show excellent potential for attenuating gamma, neutron, proton, and alpha radiation, particularly at low energies. This supports their potential use in medical and nuclear facilities. Radiation attenuation results show that the specimen with the ID HWC36Pb exhibits the maximum attenuation coefficient for gamma and neutron radiation among the other investigated specimens, which were either doped with a small quantity of lead or doped with copper. The mass attenuation coefficient of HWC36Pb at a gamma energy of 662 keV was determined to be 0.0905 cm2/g. Furthermore, it demonstrates the highest fast neutron removal cross-section, measuring 0.0944 cm−1.

Research on the effect of apparent density on the rheological properties of lightweight and heavyweight concrete

This paper investigated the influence from apparent density on rheological property of lightweight and heavyweight concrete. The apparent densities of 1761 kg/m³, 3048 kg/m³ and 3548 kg/m³ were selected. The obtained results showed when the slump for lightweight and heavyweight concrete was controlled in the range of 160 ± 10 mm, the yield stress (τ0) and plastic viscosity (μp) increased significantly as the addition of the apparent density. The slump tests of fresh lightweight and heavyweight concrete were numerically simulated with an error of less than 3.0 % using lattice Boltzmann method (LBM). The established slump model could accurately predict the flow behavior and characteristics of lightweight and heavyweight concrete at different apparent densities. By comparing the distribution of physical fields such as velocity and pressure, the effect of apparent density upon the flow behavior of lightweight/heavyweight concrete was analyzed in depth, and the changing rule in rheological performance of concrete with different apparent densities was clarified.

Improving passing ability of ultra-heavy-weight concrete by optimising its packing structure

Heavy-weight concrete (HWC) is a widely adopted radiation shielding material in the nuclear industry. In this study, two kinds of high-density aggregate, namely, iron sand (IS) and steel slag coarse aggregate (SSCA), were adopted to fully replace river sand and natural coarse aggregate, respectively, producing ultra-heavy-weight concrete (UHWC) with a unit weight >3800 kg/m3, to ensure excellent radiation shielding performance. However, IS and SSCA seriously impaired the passing ability of UHWC as the cement paste could not hold the IS and SSCA as firmly as natural aggregates, owing to their high density. To overcome this, the rheology of UHWC should be optimised by partially replacing the cement with superfine silica fume (SSF) and using a suitable amount of superplasticiser (SP) to enhance the wet packing density (WPD). A total of 28 UHWC mixes with different replacement ratios of SSF and different SP dosages were tested for segregation width, flowability, L-box passing ability, unit weight and WPD. Results revealed that incorporating an appropriate quantity of SSF and SP improved the WPD of UHWC, resulting in improved segregation resistance, enhanced flowability, increased passing ability and a higher unit weight. Lastly, there is a positive correlation between flowability, passing ability and WPD.

Reinventing concrete: Sustainable nano-alumina from metallic waste-cans and nano-ferrite for next-generation green magnetite heavyweight concrete

For the first time, sustainable nano-alumina, obtained from metallic waste-cans, is employed in green heavyweight magnetite concrete (GHMC). The GHMC mixes comprised fixed contents of 500, 125, 60, and 27.4 kg/m3 of cement, granulated blast furnace slag (GBFS), silica fume, and superplasticizer (SP), respectively. The benefits of typical magnetite heavyweight concrete was exploited alongside various percentages of research variables in different 11 mixes. The Sand (S) was used as a replacement for fine magnetite (FM) by (25 %, 50 %, 75 %), steel reinforced fiber (SRF) was added by (1 %, 1.5 %). Moreover, the nanoparticles included nano-Alumina (NA) by (2 %, 3 %, 4 %), nano-ferrite powder (NF) by 2 %, and 2 % NA+2 % NF. The effects of sand, SRF, NA, and NF were studied on slump, wet, dry, and oven dry densities, compressive strength (fc) and tensile strengths (ft), water absorption% (Wa%), electrochemical attack with chloride and sulfate, and thermogravimetric analysis (TGA), microstructure (SEM), and gamma-ray attenuation coefficient (LAC-μ, HVL, v) as shown in F ig. 1. The results revealed that adding 25 % sand, 1.5 % SRF, and 2 % NA+2 % NF boosted all of GHMC's tested properties. Although the replacement of 25 % sand slightly reduced the density of GHMC, it improved GHMC's workability, mechanical properties, and durability. Adding 1.5 % SRF resulted in an enhanced density as well as it improved all mechanical properties and durability. The fc, ft, and WA%, were enhanced by 31 %, 70 %, and 38 % at 28 days of age. The mixes incorporating 2%NA were better than those incorporating 2%NF for all testing properties. More improvements were noticed due to adding NA up to 4 %. Moreover, the mix incorporating 2 % NA+2 % NF had the best results compared to other nanoparticles percentages. For example, the dry density, fc and ft, and Wa% were improved up to 3.5 %, 66 %, 216 %, and 68 % at 28 days of age. Furthermore, the residual fc due to the exposure to chloride and sulfate was improved by 87 % and 78 % after 28 days, respectively. The TGA% at 1000 °C improved to 98.73 %, and LAC-μ improved by 83–102.4 %.

Physical and mechanical properties of light and heavyweight concretes reinforced with basalt fibre

Physical and mechanical properties of light and heavyweight concretes reinforced with basalt fibre

Radiation shielding properties of heavy-weight concrete and heavy-weight geopolymer concrete incorporating nano-ZnS

The population growth and the subsequent increase in energy demand for buildings require the widespread use of sustainable materials in the construction industry. Therefore, geopolymer concretes (GPC) are expanding with the ability to emit less greenhouse gases (GHG) compared to conventional concrete. In this study, the effect of adding different content of Zinc sulfide nanoparticle (nano-ZnS) 0, 1.5, 3, 4.5, and 6 % by weight of cement on density (ρ), compressive strength, gamma ray radiation protection characteristics, and microstructure based on scanning electron microscope (SEM) is investigated in heavy-weight concrete (HWC) and heavy-weight geopolymer concrete (HGC). The results have shown that nano-ZnS nanoparticles improve the strength and gamma ray shielding properties of HWC and HGC by modifying the microstructure so that by adding the optimal amount of 6 % nano-ZnS, the maximum compressive strength for HWC and HGC was obtained by 57.4 and 41.5 %, respectively. In addition, the highest linear attenuation coefficient (µ)was obtained with the addition of 4.5 % nano-ZnS for HWC and HGC, 12.8 and 8.9 %, respectively.Furthermore, the life cycle assessment (LCA) of the three phases of raw material production, transportation and concrete production has revealed that HGC has emitted 41.5 % less CO2 compared to HWC. In general, HGC in the presence of the optimal amount of nanoparticles has shown a more visible improvement in compressive strength and gamma ray shielding properties. In addition, HGC as an environmentally friendly material, has significantly reduced the emission of CO2.

Evaluation of mechanical strength, gamma-ray shielding characteristics, and ITZ microstructural properties of heavyweight concrete using nano-silica (SiO2) and barite aggregates

This research assessed the mechanical performance, gamma-ray shielding, and interfacial transition zone (ITZ) microstructural properties of concrete mixes that incorporate barite coarse aggregates and nanosilica. To achieve this goal, several concrete mixes containing normal coarse aggregate (NC), barite aggregate (BC), and nano-silica/barite aggregates (NSBC) were fabricated. Several properties such as workability, mechanical strength, electrical resistivity (ER), ultrasonic pulse velocity (UPV), chloride migration (RCPT), and gamma shielding were comparatively assessed for these concrete mixtures. In addition, analytical characterizations viz., x-ray diffraction (XRD), Fourier transform infrared (FTIR), scanning electronic microscopy (SEM), and energy dispersive x-ray (EDX) were employed to study the ITZ microstructure at mortar/aggregate interface of concrete mixtures. The results showed that barite concrete incorporating nanosilica (NSBC) exhibited higher density and improved mechanical properties compared to both normal concrete (NC) and barite concrete (BC). Specifically, concrete mixture containing barite aggregate and 3% nanosilica (3NSBC) content exhibited improved impermeability and reduced concrete porosity. The gamma-ray shielding properties for 3NSBC were superior among all concrete mixtures. After 28 days, 3NSBC exhibits higher compressive strength (18.26% and 14.76%) and greater shielding capacity (12.82% and 6.66%) compared to NC and BC, respectively. The analytical characterizations results have demonstrated that nanosilica helps prevent the accumulation of calcium hydroxide in the ITZ by utilizing it to form calcium silicate hydrate. This leads to the development of a more compact and denser microstructure in the ITZ of nano-silica-based barite concrete (NSBC). Furthermore, it was revealed that, the incorporation of nanosilica exceeding 3% led to agglomeration, resulting in a weaker ITZ within the concrete leading to overall reduction in concrete properties.

Mechanical properties, attenuation coefficient, and microstructure of ultra high-performance heavyweight concrete for radiation shielding applications

This paper explores the characteristics of ultra-high-performance heavyweight radiation shielding concrete by using many types of radiation-resistant aggregates. The experimental work is carried out in two groups, The first group contains six mixes that are prepared by using barite, basalt, and serpentine as heavyweight coarse aggregate, and the second group contains six mixes that are prepared by using the same percentages of coarse aggregate in the first group while partially replacing the fine aggregates with hematite. The main research aim is to study radiation absorption characteristics using 60Co sources that discharge 1.25 MeV photons. Linear attenuation coefficient, half-layer value, and tenth-layer value layers were assessed as radiation absorption characteristics. In addition, the hardened characteristics of all mixes like compressive, tensile, flexural strengths, and modulus of elasticity have been investigated, also, microstructure has been tested. Based on the results, The density of mixtures ranged between 2690 and 3080 kg/m3. The largest value of concrete density was recorded for barite with hematite. Although basalt with hematite gave the maximum compressive strength value of 155.8 MPa. Barite with hematite improved the radiation protection properties compared to basalt with sand by 20 % as the Linear attenuation, HVL, and TVL values became 0.173 cm−1, 4.01 cm, and 13.28 cm respectively.

Mechanical and durability properties of structural grade heavy weight concrete with fly ash and slag

The paper investigates the fundamental mechanical and durability properties of a M50 strength grade heavy weight concrete (HWC), with replacement of cement by fly ash at 15 %, 25 % and 35 % levels and slag at 40 %, 50 % and 60 % levels. The mechanical properties studied include compressive strength, elastic modulus, flexural and split tensile strengths, and the durability properties include water permeability, drying shrinkage and carbonation behavior. Although extended curing improves mechanical strength and water permeability properties of fly ash and slag blended HWCs, fly ash replacement reduces the modulus of elasticity of HWC to some extent. A simple relationship was used to estimate the elastic modulus of fly ash and slag based HWCs from their density and compressive strength, and the estimated values agreed well with the experimental results. Experimental investigation shows that the long term drying shrinkage strain for all fly ash based HWCs (15 %–35 %) is lesser than that for the 100 % ordinary portland cement (OPC) and all slag based HWCs. The resultant hardened density variations of fly ash and slag blended concretes exposed to long term controlled environment discussed in this paper can be used for estimating shielding thickness of HWC members against ionizing radiations. The carbonation resistance of fly ash and slag HWCs exposed to 3 % CO2 condition for 146 days is also evaluated. Accelerated carbonation coefficients (kacc) estimated for all types of HWCs show that the carbonation resistance of HWC prepared with 15 % fly ash and 40 % slag is comparable. The rate of accelerated carbonation of HWCs increases for the increase in replacement level of fly ash and slag. In addition to the higher rate of carbonation, increase in calcium carbonate content estimated through micro analytical studies also suggest that a higher level of slag replacement reduces the carbonation resistance of HWC significantly.

Influence of heavyweight aggregate on the fresh, mechanical, durability, and microstructural properties of self-compacting concrete under elevated temperatures

Recently, attention has been drawn to the production of heavyweight self-compacting concrete which combines the benefits of heavyweight concrete (HWC) and self-compacting concrete (SCC). This paper investigates the effect of using the barite coarse aggregate (size 4–8 mm) as substitution of volume of the natural coarse aggregate (size 4–8 mm) with various percentages (0, 20, 40, 60, 80, and 100%) on self-compacting concrete (SCC) properties. Slump-flow, T500 time, V-funnel, J-ring, L-box test, and fresh density were used to evaluate the fresh SCC characteristics. However, compressive strength, flexural strength, splitting tensile strength, water absorption, dry density, sulphate attack, and ultrasonic pulse velocity were used to evaluate the mechanical and durability characteristics. In addition, the impact of elevated temperatures (600 °C and 800 °C) on SCC containing various ratios of barite was studied through the evaluation of the density and compressive strength losses. Also, using fourier transform infrared radiation (FTIR) technique, mercury intrusion porosimetry (MIP), and scanning electron microscope (SEM), a microstructural investigation was conducted on hardened SCC containing various ratios of barite to determine the behaviour of barite in comparison to the control mix. The results demonstrate a slight negative effect on fresh and hardened of SCC properties with increasing percentages of barite. However, concrete incorporating up to 80% barite fulfilled all of the EFNARC-recommended criteria for SCC and the dry density of samples containing 80% barite was 2.660 kg/m3. Therefore, the self-compacting and heavyweight concrete characteristics were met by incorporating 80% barite as coarse aggregates. Nevertheless, the rate of increment in compressive strength increased with increasing barite ratios after exposure to 15 cycles of sulphate attack compared to the non-exposed samples.

Effect of heavy-weight recycled materials on radiation shielding and properties of high-strength concrete with CEM III

This research aims to study the effect of replacing up to 100% of recycled coarse aggregates with heavyweight aggregates. In addition to the effect of adding heavyweight aggregate slag on the efficiency of shielding against radiation and on the mechanical physical properties and elevated temperature of heavyweight high-strength concrete (HWHSC). In this investigation, HWHSC mixtures incorporate lead slag (LS), copper slag (CS), and steel slag (SS) as coarse aggregate. Recycled heavyweight coarse aggregates are added to concrete mixtures at volume ratios of 0%, 25%, 50%, 75%, and 100%. Slump test, compressive strength, flexural strength, tensile strength, elastic modulus, and bulk density tests were carried out. Three different gamma-ray energies at 137Cs 662, 60Co 1173, and 60Co 1332 (keV) sources were used to evaluate the mass attenuation coefficient, linear attenuation coefficient, half and tenth-value layer, and mean free path. To evaluate the impact of elevated temperature on density, compressive strength, and radiation shielding properties, concrete mixtures were exposed to 22 °C, 300 °C, 500 °C, and 800 °C. Compared to basalt-based concrete, heavy-weight concrete (HWC) incorporating LS, CS, and SS coarse aggregate has a significantly higher density. The results show a good effect of recycled heavyweight coarse aggregates on fresh, mechanical, and radiation-shielding properties. The density of the developed high-strength concrete (HSC) mixes ranges between 2400 and 3370 kg/m3, and the increase in recycled heavyweight coarse aggregates replacement ratio up to 75% increased all mechanical characteristics of HWC mixtures. Using LS as a replacement of basalt by 75% resulted in the highest compressive strength, splitting tensile strength, flexural strength, and elastic modulus of 105.8 MPa, 14.2 MPa, 19.5 MPa, and 45.76 GPa, respectively. Compared to basalt, LS, CS, and SS eliminate the impact of elevated temperatures on HSHWC strength. The best radiation protection properties were achieved with the complete replacement of basalt by LS.

Development of 3D printed heavyweight concrete (3DPHWC) containing magnetite aggregate

The main objective of this study is to develop 3D printed heavyweight concrete (3DPHWC) to produce elements with a dry density of up to 3500 kg/m3 by replacing natural aggregate (SA) with magnetite aggregate (MA) up to 100%. A comprehensive systematic study was conducted to thoroughly assess mixtures' mechanical properties, physical proficiency, fresh properties, and printing qualities. The inclusion of MA exhibited the desired fresh properties required for 3D printing and promising physical and mechanical properties. Evaluation of the mechanical properties of designed 3DPHWC indicates that replacing SA with MA increases both cast and printed samples' strengths. The 3D printed M100 sample achieved higher 28 days flexural and compressive strengths by 18 % and 20%, respectively, compared to printed control mix (M0). Micro-CT study correspondingly demonstrated improvements in the composites' porosity, pore size, and pore morphologies. The linear attenuation coefficients (LACs) and half-value layer (HVLs) for slow neutron and gamma-ray were measured to assess radiation shielding characteristics. A significant performance improvement was obtained for slow neutrons by introducing the magnetite aggregate. Unlike slow neutrons, no significant difference was observed between cast and printed samples against γ-rays. Moreover, the effect of porosity on the shielding performance was discussed.

Effect of metakaolin and boron-carbide on the properties of magnetite, basalt and quartz concrete at different elevated temperatures

Nuclear buildings are important radiation-shielding structures. They must be shielded against radiation, fire, or heat during service life. Therefore, thermal properties and behaviour under elevated temperatures are essential in designing the nuclear structure. Furthermore, heavyweight concrete is essential for fire resistance in nuclear buildings. Mineral additives improve the physical, mechanical and fire resistance properties. The paper studied the influence of metakaolin and boron carbide additives on the thermal, mechanical and microstructural properties of magnetite, basalt and quartz concrete. Visual observations, residual mechanical properties and microstructural observations using (SEM) were studied at 20, 150, 300, 500 and 800 ℃. Results showed the enhancement of the compressive strength up to 300 ℃ upon using metakaolin and boron carbide additives. As well as metakaolin and boron carbide caused the spalling of magnetite concrete, where the compressive strength had shown a steep decline above 500 ℃. Furthermore, metakaolin and boron carbide positively influenced the strength properties of basalt and quartz concrete by reducing the permeability level and hindering the decomposition level of CSH. The Scanning Electron Microscopy (SEM) images associated the role of metakaolin and boron carbide in improving cement gel structure and reducing the decomposition level of the concrete.

Workability Assessment of Pumpable Structural-Grade Heavy-Weight Concrete Using Novel Coaxial Cylinder Method

The mixture proportioning of heavy-weight concrete (HWC), as seen from the literature, is primarily based on a trial-and-error approach; even so, data from the literature indicate that obtaining high-slump mixtures for high density levels (more than 3.1 g/cm3) is difficult. Because heavy-density aggregates are prone to segregation at high slump, a low water to cement ratio is generally used for HWCs, and full-scale pumping trials are needed for checking pumping placement. For structural-grade HWCs used in nuclear facilities and specific infrastructure such as tunnel cross-rail floating slabs, rheological properties are needed to quantify the workability for pumping placement. Because use of rheological assessment methods using sophisticated rheometers cannot be realized easily onsite, a novel coaxial cylinder method is proposed in this study for determining the yield stress of HWCs delivering 3,800 to 3,900 kg/m3 density. The device proposed in this study is portable and can be used also onsite. Four structural-grade hematite aggregate HWCs, with design strengths varying from 40 to 70 MPa, were designed with ordinary portland cement. To understand the effect of fly ash addition on rheological behavior, one of the structural-grade HWC with three different levels (15%, 25%, and 35%) of fly ash was investigated. For referring the initial workability and workability retention properties of HWCs used in jobsite pumping, the conventional slump test values of the mixture were compared with yield stress measurements. Experimental investigations suggested that the method proposed in this study are able to adequately capture the workability characteristics required for pumpable mixtures. Further, it was seen that 35% partial replacement of fly ash resulted in 100% reduction in yield stress of HWC mixtures. Fly ash replacement (15% to 35%) did not significantly alter the hardened concrete density (3,800 kg/m3); however, attainment of the specified compressive strength depended on the replacement level of fly ash and extended curing period.

Dynamic responses of radiation-induced heavyweight concrete subjected to biaxial compression

As a good shielding material, heavyweight concrete is largely utilized for building the Concrete Biological Shielding (CBS) wall of the commercial nuclear power plant, and is often subjected to the biaxial loadings with a strain rate possibly varying from 10−5s−1 to 10−2s−1. This paper assesses the combined effects of the lateral stress and the strain rate on the compressive strength of radiation-induced heavyweight concrete on the example of serpentine concrete. For this goal, a 3-dimensional rectangular numerical concrete specimen containing special aggregates and ITZs was firstly established. Exposed to neutrons of different fluences, the initial damages caused by the fast neutron were assessed by a thermal-mechanical approach. Then, a series of static and dynamic biaxial compressive tests on the rectangular specimens having initial damages of different degrees were carried out by finite element analysis via ABAQUS. The failure modes, the crack patterns, and the ultimate compressive strengths of the pre-irradiated serpentine concrete were obtained numerically. Finally, based on the numerical results and the classical "Kupfer-Gerstle" ("K-G") criterion, this paper derives the biaxial strength criterion of the radiation-induced heavyweight concrete undergoing both lateral stress and strain rate. Through the formula, it was found that the fast neutron fluence of high level reduces significantly the biaxial compressive strength of the heavyweight concrete. Besides, if the heavyweight concrete undergoes additionally lateral stress and the strain rate, the biaxial compressive strength could be enhanced. The enhancement effect was maximized at the lateral stress ratio of 0.5 and the strain rate of 10−2s−1. The current numerical approach was developed with a potential application to the lifetime extension of the heavyweight concrete infrastructures used in commercial nuclear reactors.

Behaviour and design of heavy-weight concrete-filled spiral welded columns

This study explores the mechanical performance of heavy-weight concrete-filled mild/stainless steel tubular columns under axial compression. An experimental programme comprising six short and six long circular specimens was carried out, in which a special mixed heavy-weight concrete (HWC) with a self-compacting nature was utilised to assist the widespread of such structural components. Comprehensive numerical analysis was also performed after the validations against the obtained test results. Specifically, the developed numerical models included a constitutive relationship for the confined HWC, with which the tested columns' compressive behaviour (particularly the less ductile post-peak behaviour) can be reproduced accurately. Based on obtained experimental and numerical results, the loads shared by the outer spiral welded circular tube and infilled concrete have been separated and traced. This has assisted in a clear and accurate identification of the resistance capacity contributed by individual components. A refined solution for the design of circular heavy-weight concrete-filled mild/stainless steel tubular columns has been proposed accordingly. Moreover, together with the experimental results, a series of numerical analysis were also performed to assess the applicability/accuracy of the existing design specifications regarding the member capacities of long columns, where global buckling effects were considered.

Strength and nuclear shielding performance of heavyweight concrete experimental and theoretical analysis using WinXCom program

This study presents experimental work and theoretical analysis to evaluate the performance of heavyweight concrete for nuclear shielding applications. Heavyweight concrete mixes were prepared using different coarse aggregates including crushed dolomite, magnetite and steel. Also, magnetite and steel filings were used to replace 50% and 100% by volume of the sand. The workability of fresh concrete and the compressive strength at 7 and 28 days were evaluated. The attenuation coefficient for concrete samples was determined using gamma-ray spectrometry and WinXCom software in gamma-energy lines of 0.662–1.332 MeV. The experimental results indicated that the concrete mixes containing steel particles as a coarse and fine aggregates achieved the most desirable performance in terms of density and gamma-attenuation. Concrete densities up to 5.8 ton/m3 were obtained using steel as coarse aggregates. For the examined photon energy lines, the average attenuation coefficient of the concrete mixes incorporating steel was two times that of the control mix. On the other hand, the concrete mixes incorporating magnetite achieved the highest compressive strength value of 68 MPa. The attenuation coefficient could be estimated theoretically using WinXCom with errors in the range of 12% to −15%.

Strength Reduction of Concrete Subjected to High Temperatures: Effects of Various Aggregates

Previous studies on the strength degradation of concrete subjected to high temperatures were analyzed. To analyze the effect of the coarse-aggregate type on strength degradation, data from previous studies were collected, and the coarse aggregate used, physical properties of the aggregate, and heating conditions were analyzed. The concrete types were classified into normal, heavyweight, and lightweight concrete. Their high-temperature characteristics were analyzed and evaluated according to the mixed coarse aggregate. Finally, the correlations derived from the analysis results were compared with the CEB Code. The analysis results were different for different concrete and coarse-aggregate types, and different tendencies from the CEB Code were observed.

Gamma Radiation Effect on Normal Weight Concrete, Heavy Weight Concrete, Steel Bars, and Fiber Bars

Gamma Radiation Effect on Normal Weight Concrete, Heavy Weight Concrete, Steel Bars, and Fiber Bars

Radiation shielding performance of seawater-mixed concrete incorporating recycled coarse aggregate and steel slag

Concrete production entails a high amount of freshwater consumption. Moreover, as heavy-weight concrete production is cost-inefficient for mass structures, such as radiation shielding facilities, the need for seawater and other recycled/waste materials to produce sustainable concretes for radiation shielding applications cannot be overemphasized. Hence, this paper investigates the radiation shielding performance of fresh water and seawater-mixed concrete mixes produced using various waste coarse aggregates, including recycled aggregate and electric arc furnace steel slag (EAF-SS). Partial simultaneous replacements of the two coarse aggregate types are also considered. Aimed at addressing material sustainability, a total of ten such concrete mixtures were designed and produced by varying the type of mixing water with different combinations of the normal and waste coarse aggregates while maintaining the cement content and water/cement ratio constants. These mixtures were then tested for their unit weight, compressive strength, and nuclear radiation response through gamma-ray intensity detection. The mixes' compressive strengths ranged from 30.8 to 49.8 MPa, all of which met the specifications for structural concrete. Linear attenuation coefficients were computed based on the radiation experimental results for the different mixes. Three of the specimens passed the minimum requirement to be considered heavy-weight concretes. Regardless of concrete strength, the unit weight of the mixes and the type of water (fresh versus seawater) used for mixing had an impact on radiation shielding performance. The maximum compressive strength was attained in the fresh water-mixed concrete fully incorporating EAF-SS as coarse aggregate – 13% over that of the concrete with natural aggregate. Moreover, the use of EAF-SS enhanced the radiation shielding performance of concrete by 13–19%. Using local seawater improves radiation shielding by 4–5% while pursuing sustainable concrete production for nuclear applications. A mixture's unit weight and chemical composition – particularly the existence of hematite – are crucial factors in the effectiveness of radiation shielding. The variations in gamma-ray transmission reductions between mixtures confirm the feasibility of the materials utilized.