Steel Waste Research Articles

Strength Properties of Sustainable Mortar Containing Waste Steel Slag and Waste Clay Brick: Effect of Temperature.

The use of waste streams for the production of sustainable cement-based materials cannot be overemphasized. This study investigates the feasibility of reusing waste steel slag (WSS) and waste clay brick (WCB) as a replacement for natural sand (NS) in mortar. Numerous studies have reported mainly the compressive strength of concrete/mortar, while limited research is available that focuses on the tensile and flexural strength of mortar, and especially the performance at elevated temperature. Hence, this study investigates the tensile and flexural strength of mortar with three different replacement percentages (0, 50 and 100% by volume of NS) of NS by WSS and WCB at normal temperature (without thermal treatment) and after exposure to elevated temperatures (250, 400 and 600 °C). At ambient condition, both tensile and flexural strength were enhanced as the WSS content increased (76 and 68%, respectively, at 100% WSS). In comparison, the strength increased at 50% WCB (25 and 37%, accordingly) and decreased at 100% WCB (23 and 20%, respectively) compared to 100% NS. At elevated temperatures, both the tensile and flexural strength of mortar mixes decreased significantly at 600 °C.

Investigation on mechanical properties and deformation behavior of copper-based three-phase metal matrix composite: Experimental and micro-macro-mechanical finite element analysis

The present study involved development of copper-based metal matrix composite, reinforced with waste EN 31 steel chips and TiB2 ceramic particles. Waste EN 31 steel chips and TiB2 ceramic particles were ball-milled for 100 h to obtain a single entity. The composite material was produced with a stir-casting technique, followed by a squeeze pressure process. The addition of Cu + 10 wt% of waste steel chips + 5 wt% of TiB2 improved the tensile strength of the copper matrix by about 68.35%. Furthermore, the addition of Cu + 5 wt% of waste steel chips + 10 wt% of TiB2 and Cu + 12.5 wt% of waste steel chips + 2.5 wt% of TiB2 increased the hardness and toughness of the copper matrix by about 133.33% and 28.57%, respectively. The addition of Cu + 10 wt% waste steel chips + 5 wt% of TiB2 ensured minimal corrosion weight loss in the metal matrix composite as a result of low porosity and a strong bond between the molecules. Further, representative volume element (size: 225 × 225 × 225 nm)-based finite element analysis was done to explain the micro-mechanical deformation, interfacial strength of matrix-particle interaction and damage behavior of Cu + 10 wt% of waste steel chips + 5 wt% of TiB2 metal matrix composite. A user material sub-routine model was also written and implemented with the help of FORTRAN subroutines to simulate the macro-mechanical tension test process of Cu + 10 wt% waste steel chips + 5 wt%TiB2 metal matrix composite. The results revealed a good agreement between the micro-mechanical and macro-mechanical finite element analysis models on the one hand and the experimental results on the other. Further, the representative volume element (with matrix and particles) showed about 59% and 66.5% higher tensile strength compared to the matrix–particle interface and the matrix (without particles), respectively. The percentage difference between the micro-mechanical finite element analysis and the experiments as well as the macro-mechanical finite element analysis and the experiments was found to be 5.58% and 9.64%, respectively. The finite element analysis results established that the waste steel chip powder particles exhibited greater stress than the TiB2 powder particles.

Laboratory Investigation and Numerical Modelling of Concrete Reinforced with Recycled Steel Fibers.

In the last decades, fiber reinforced concrete have emerged as the possible key to revolutionize civil engineering. Among different types of fibers employed in concrete technology to date, the application of recycled steel fibers produced from end-of-life car tires appears to be a viable approach towards environmentally friendly construction. In this study, we demonstrate the laboratory research and numerical analysis of concrete reinforced with waste steel fibers recovered during the recycling process of end-of-life car tires. Concrete mixes with the following fiber contents: 0.5%, 0.75%, 1.0%, 1.25%, and 1.5% per volume were prepared and then tested in three-point bending conditions. The laboratory investigation revealed highly boosted properties of concrete under flexure. We further performed the finite element method (FEM) analysis of 2D models using Atena software in order to develop a material model allowing the numerical modelling of recycled steel fibers reinforced concrete (RSFRC) behavior. The parameters of RSFRC material model have been modified using the inverse analysis until matching the experimental performance of the material. The results, being in good agreement with the laboratory investigation, have indicated a high potential of RSFRC for real scale construction applications.

Effect of pumice powder and nano-clay on the strength and permeability of fiber-reinforced pervious concrete incorporating recycled concrete aggregate

Pervious concrete (PC) has been widely used to construct concrete pavements and to increase the permeable surfaces all over the world. With the boost in the use of PC, it is necessary to make it more environmental-friendly and cost efficient. This study investigates employing recycled concrete aggregate (RCA) and pozzolanic additives as a partial replacement (PR) of natural coarse aggregate (NCA) and Portland cement, respectively. For this purpose, the NCA was replaced with 10%, 25%, 50% and 100% RCA and the Portland cement was replaced with 10%, 25% and 50% pumice used in combination with 1–3% nano-clay (NC). The compressive and flexural strengths, void content, density, and permeability of concrete were evaluated. Moreover, the effect of adding three different types of fibers including steel fiber (STF), macro-fiber (MF), and waste plastic fiber (WPF) at volume fractions of 1% and 2% on the properties of concrete was studied. A total number of 7791 specimens from 371 mixtures were cast and tested. Using RCA decreased density, compressive strength (CS) (up to 58%) and flexural strength (FS) (up to 64%) and increased the void content and permeability (up to 15%) of concrete. The use of pumice generally reduced the early-age strength of concrete; however, using 10–25% pumice increased the mechanical strength at 90 days. Incorporating 1–3% NC also had positive effects on the strength properties and led to a minor reduction in permeability. STF performed better than MF and WPF, and adding 1% STF, MF, and WPF increased the 180-day FS of RC25 by 78.9%, 67.4% and 37.1%, respectively. The effectiveness of fibers declined with the increase in RCA content, which could be related to the poor compaction of concrete. According to the test results, the 90-day CS of mix RC50Pu25 with 2% STF and mix RC100Pu10NC1 was equal to the control mix. Therefore, it sounds that it is a feasible approach to significantly reduce the consumption of NCA and cement by using specific dosages of the other materials used in this study.

Factors affecting multiple persistent organic pollutant concentrations in the air above Japan: A panel data analysis

Numerous reports have elucidated different statistical approaches to identify temporal trends in atmospheric persistent organic pollutant (POP) time series. However, the correlation of industrial activity with concentrations of atmospheric POPs in Japan has not yet been determined. Herein, a panel data analysis of a 16-year monitoring program (2003–2018) conducted by the Japanese Ministry of Environment was used to investigate a range of POPs in the atmosphere above Japan. This work focuses on polychlorinated biphenyls (PCBs), polychlorinated naphthalenes (PCNs), polybrominated diphenyl ethers (PBDEs), hexachlorobenzene (HCB), and pentachlorobenzene (PeCBz) collected each year at 53 sites across Japan. The panel analysis revealed that PCB, PCN, and PBDE concentrations were influenced by a combination of factors including year, industrial activity (municipal and industrial waste incinerators, cement kilns, steel industry, and secondary zinc production), population, temperature, and atmospheric boundary layer. However, HCB and PeCBz were not significantly affected by these factors. Industrial activity showed stronger positive correlations with all homologues of PCBs, PCNs, and PBDEs as compared to those demonstrated by population. Significant decreasing trends were identified for the atmospheric ∑PBDEs (half-life t1/2 = 9.4 years), ∑PCNs (t1/2 = 8.9 years), and ∑PCBs (t1/2 = 13.5 years) concentrations, while HCB and PeCBz showed slightly increasing or steady levels. As a statistical tool, panel data analysis can contribute to the assessment of spatial and temporal trends of POPs at a national scale, while elucidating different behavioral responses to numerous environmental variables.

Mechanical Performance of Recycled Aggregate Concrete Containing Lathe Waste Steel Fibre

The increasing demand, diminishing supplies, and growing pressure on natural resources have necessitated recycling and reusing waste. Several kinds of research have been done on the reuse and recycling of debris from building projects. Thus, with a view to the reuse of waste materials, the elimination of environmental contamination, the reduction of overhead costs of concrete, and the extension of the service life of concrete structures, this research aimed to study the feasibility of utilizing recycled concrete aggregate (RCA) with constant inclusion of waste steel fibre (LWSF) in concrete by evaluating its workability, compressive and splitting tensile strengths. A concrete mix ratio of 1:2:4 by weight of cement, sand, and granite was adopted with a water-cement ratio of 0.45. Five different concrete mixes were prepared in this study; one normal aggregate concrete (NAC) and four (4) other mixes with 25%, 50%, 75%, and 100% recycled aggregate content with a constant 1.5% addition of LWSF. The result of workability shows a reduction with an increase in the percentage replacement level. The recycled aggregate concrete (RAC) was characterized by lower compressive strength as compared with the NAC. When the replacement ratio increased from 25% to 50%, a significant reduction of about 14% and 30% were observed in the compressive strength at 7-days, but at 28-days slight increase in the compressive strength was observed. Also, a decrease in splitting tensile strength as the percentage replacement of crushed granite (CG) with RCA is increased was observed. Overall, the findings showed that the RAC-containing LWSF is environmentally sustainable and would significantly reduce the global greenhouse impact and building materials' overall quality.
 Keywords: Recycled concrete, lathe waste, steel fibre, compressive strength, tensile strength

An indigenous iron-reducing microbial community from MX80 bentonite - A study in the framework of nuclear waste disposal

Highly compacted MX80 bentonite has been selected as the engineered buffer and backfill material in several proposed concepts for long-term deep geological storage of nuclear waste. Iron-reducing bacteria reduce Fe (III) to Fe (II) and some are adapted to high temperatures and desiccated environments, in keeping with periods of less habitable conditions within the repository. In one potential UK repository concept, iron from carbon steel canisters may contribute to an iron-rich environment at the clay-canister interface. This could lead to changes in the mineralogy and iron-content of MX80 bentonite due to variation of the redox state and solubility, which in turn could alter the geomechanical properties of the clay. To investigate the potential role of iron-reducing bacteria in this process enrichments were carried out with both commercially available MX80 bentonite powder and compacted MX80 bentonite to identify the presence of an indigenous iron-interacting community in the clay. Throughout these enrichments Fe (II) soluble, Fe (II) total, and pH were measured, and the enrichments were subjected to 16S rRNA community analysis. Concentrations of Fe (II) total peaked at day 28 in all enrichments; however, the concentration was overall higher when accompanied by bacterial growth. Fe (II) soluble remained low throughout. 16S rRNA gene sequencing revealed the presence of several putative iron-interacting bacteria, as well as thermotolerant and spore-forming species. The indigenous community was largely comprised of firmicutes, including iron-reducers and spore-forming bacteria such as Desulfosporosinus. Therefore, MX80 bentonite inherently carries a viable microbial community which could potentially interact with structural iron present within MX80 bentonite or other mineral components, such as a carbon steel waste canister. Various research has shown that microbial activity is unlikely within the bulk bentonite provided high compaction is maintained. The importance of this high compaction is highlighted by the finding here of a viable, robust and functionally diverse community within the clay and activity may be possible anyway at edge sites and interfaces where, locally, swelling pressures might not fully develop.

A Zero-Waste Multi-Criteria Decision-Support Model for the Iron and Steel Industry in Developing Countries: A Case Study

The iron and steel industry is a major global industry that consumes vast quantities of energy and causes environmental degradation through greenhouse gas emissions and industrial waste generation, treatment, and disposal. There is a need to manage complex iron and steel industrial waste in Africa, which requires a system engineering approach to zero waste management as informed by multi-criteria decision-making. The purpose of the current study was to develop a hybrid four-step multi-criteria decision-support model, the i-ZEWATA (Industrial Zero Waste Tiered Analysis). I-ZEWATA acts as a road map to understand, design, assess, and evaluate the iron and steel industrial waste systems with the ultimate objective of moving towards and achieving a zero-waste footprint. The results demonstrate that iron and steel waste can be identified, visualized, prioritized, and managed to promote zero-waste by applying a system-engineered approach. Additionally, relationship patterns to environmental, social, operational, and economic aspects with system behavioral patterns and outcomes were identified. It was clear from the case study in South Africa that, although technology and solution investment is essential, waste management, valorization, and treatment components require a concerted effort to improve industrial waste operational management through effective zero-waste decision-support towards a circular economy.

Radiation shielding properties of mortars containing heavyweight particles

Abstract In this study the radiation shielding properties of mortar samples were investigated. The samples were created by replacing heavyweight particles of iron, steel and chromium waste by calcareous sand in different volume percentages. Additionally, the effects of the physical properties of particles and samples on shielding properties is also discussed. In the scope of this work, the radiation shielding properties of mortar samples were measured by determining the values of mass attenuation coefficients by means of an experimental setup consisting of 133Ba, 137Cs and 60Co standard point sources and high purity germanium (HPGe) detector. It’s concluded that the highest mass attenuation coefficient values among the heavy particles were achieved by chromium particles. However, all the high-density particles used in the study improved the radiation shielding properties of the mortars considerably compared to ordinary mortars.

Plasticity and Strength Behaviour of Marine Clay Stabilized with Waste Steel Dust for Soil Improvement Works

Soft marine clay soil is characterized with highly compressible behavior, in which associated with poor bearing capacity and low in shear resistance. Soil improvement works are carried out to reduce the soil failure and destruction to the superstructure. Various techniques available for soil stabilization including the use of admixture to improve the engineering properties of the problematic soil. This paper aims to report on the use of waste steel dust retrieved from the medication supply industry as soil stabilization agent. Several series of Atterberg limit test and Unconfined Compressive Test were carried out to foresee the potential use of the waste steel dust for the purpose of civil engineering applications. The significant findings from this study is evident that the waste steel dust ranges from 5% to 15% did not able to serve as soil stabilization agent. It can reduce the plastic behavior of the soil sample; however, it also caused the strength of the soil declined. In comparison with previous studies, the presence of activated agent could possibly enhance the performance of waste steel dust as an alternative treatment agent to soil improvement works. The use of activated agent is to serve as pozzolanic materials to create cementitious bonding in between the soil interparticles matrix.

Buckling behavior of double-layered composite cylindrical shells

Composite shells of revolution are widely used as pressure vessels, reservoirs and tanks, rocket, spacecraft parts and in different elements of the building. The aim of this study is to investigate the buckling and post-buckling behavior of the cylindrical shell made of mild steel filled with melted waste polymer, polypropylene, filled with the silicon and the steel adhesive. Furthermore, seven thin-walled cylindrical shell specimens with different composite cover subject to hydrostatic pressure were tested in the present work. The results of testing under different theories and codes are compared. Also, one specimen was without composite cover (perfect model), which used to check other specimens. This study shows that the initial buckling value of all other specimen tests was higher than the perfect specimen and double layer CFRP coiling have a significant effect on the initial buckling value. However, using material between two cylinders instead of CFRP wrapping increased initial buckling value compared to the perfect specimen. The use of melted PP was more effective than other materials (silicone, steel adhesive glue and waste polymer).

Investigating the environmental pollution caused by steel slag in Dana steel rolling mill plant, Katsina

Presence of heavy metals in the soil may contaminate the surrounding environment which causes chronic diseases. The waste steel slag in Dana steel rolling mill Katsina, Nigeria is always dumped within the premises of the company. Therefore, this research examined the level of environmental pollution caused by the deposited steel slag. Minipal 4 version of PW4030 X –Ray Fluorescence Spectrometer (XRF Spectrometer) was used to analyse the chemical composition of sample A (slag), sample B (mill scale), sample C (humus soil) and sample D (humus soil and slag) at Centre for Energy Research and Training, Ahmadu Bello University, Zaria, Kaduna State, Nigeria. Chemical compounds were detected in all the samples with oxides, Fe2O3 (11.8% - 86.13%) and SiO2 (4.41% - 57.7%) dominating. Product moment correlation coefficient was used to compare the effect of Slag (sample A) on Humus soil (sample C). The result obtained has shown that, the calculated value r = + 0.763 is greater than the table value r = + 0.483 at 5% level of significance and 15 d.f. This indicates that, the correlation between the two samples is highly significant. Fe2O3, MnO and ZnO trace elements in the humus soil were enriched after cultured with slag sample and P2O5, K2O, CaO, and SO3 trace elements that are useful for plants growth and development were leached.

Processing of ferrous iron and steel waste in the context of the circular economy

The paper presents the possibilities of exploiting the small and powdered ferrous waste with the production of lighters that can be used as a raw material in the loading of the steel processing units. The capitalization of small ferrous and powdered iron and steel wastes is an important problem, because their transformation into by-products, so in economic goods can lead to a rational exploitation of the resources of raw materials and energy, thus ensuring both the needs of the human society and the protection of the environment surrounding.

Iron oxide nanoparticles obtained from steel waste recycling as a green alternative for Congo red dye fast adsorption

Iron oxides can be applied as adsorbents to remove harmful substances from the water used in the textile process. If these oxides can be synthetized through acid digestion of ferrous metal compounds, they can create a cycle of pollutants control from pollutant materials. In this study, two iron oxides were synthetized from steel waste, through razor blades (RB) and bottle caps (BC) acid digestion followed by coprecipitation, for application as Congo red dye adsorbent. Studies about the structure, composition and materials’ properties were obtained through x-ray fluorescence, x-ray diffractometry, x-ray absorption, Fourier transform infrared spectroscopy, Raman spectroscopy, thermogravimetric analysis, UV–Vis electronic spectroscopy, nanoparticle tracking analysis, zeta potential and Brunauer, Emmett, Teller method. The structural and composition analysis showed a mixture of iron oxide phases and nanometric average particle sizes. The oxides presented maximum adsorption capacity (qmax) of 418.41 mg·g−1 for IO-RB, and 104.17 mg·g−1 to IO-BC, at room temperature. Furthermore, the particles present magnetic properties from the produced iron oxide that facilitates their removal from the system, after application. The adsorbents were characterized after adsorption through the same initial techniques; thus, the produced compounds and the adsorption capacity of each oxide were correlated.

Durability of concrete made with steel filings as a replacement of fine aggregate

Steel filings are primarily composed of steel. These steel filings are produced by grinding, shaving and cutting the various steel in the mechanical workshop or factories. The steel wastes are disposed into the landfills, rivers and oceans thereby increasing pollution. To reduce these wastes reaching the landfill sites, one solution is to reuse them in construction. There have been some studies on the strength of concrete made with steel filings, however, no study has been reported on the durability. The purpose of this research was to evaluate the durability of concrete made with steel fillings as a replacement of fine aggregate. In the current study, different replacement levels of steel fillings such as 0%, 10%, 20%, 30% and 40% have been used in the making of concrete. Cube samples were tested for durability after normal curing for 28 days. It was found that the cube looses its workability and slump, when the percentage of steel filing were increased beyond 40% as replacement of fine aggregate. The water absorption increased with increasing percentage of steel filing and the sorptivity tests showed that the weight of capillary rise of water increased with the increasing percentage of steel filing due to the increased porosity of the concrete. This type of concrete may be used for the pavement and parking lots, where there is a problem of water logging, as it would allow the water to pass through it and may help in recharge of the ground water.

Shaking Table Tests on Seismic Behavior of Geogrid-reinforced Retaining Wall with Waste Steel Slag Backfill

Shaking Table Tests on Seismic Behavior of Geogrid-reinforced Retaining Wall with Waste Steel Slag Backfill

Adsorptive Removal of As(V) from Aqueous Solution onto Steel Slag Recovered Iron – Chitosan Composite: Response Surface Modeling and Kinetics

In the present work iron particles was recovered by dry magnetic separation, from waste steel slag, doped with chitosan for adsorbent prepared, characterized and evaluated for the removal of As(V) from an aqueous solution. The adsorption of As(V) was optimized by using response surface methodology through Box-Behnken design model, which gave high correlation coefficient (R2 = 0.9175), and a predictive model of quadratic polynomial equation. Analysis of variance and Fischer's F-test were used to govern the parameters which interrupt the adsorption of As(V).The adsorbent was characterized by FTIR, XRD and SEM. Optimal conditions, including adsorbent dosage, pH, temperature, initial ion concentration and contact time for the removal of As(V), were found to be 0.8 g, pH 4, 308 K, 10 mg L−1 and 3 h, respectively. Langmuir isotherm model fitted better compared to the Freundlich model having a maximum adsorption capacity of 11.76 mg g−1, a high regression coefficient value of 0.993 and least chi-square value of 0.1959. The process was found to follow monolayer adsorption and pseudo-second-order kinetics. Thermodynamic parameters such as ∆S, ∆H and ∆G indicated the feasibility, spontaneous and endothermic nature of adsorption. Successful regeneration of the adsorbent implies its applicability to the removal of arsenic from real life wastewater.

Experimental study of the effect of waste steel scrap as reinforcing material on the mechanical properties of concrete

This research presents an experimental finding on the mechanical properties of concrete with waste steel scrap. The recycling of scrap metal as a concrete base reinforcement eliminates the issue of disposal. The laboratory tests for compressive strength and splitting tensile strength were conducted for different percentages of waste steel scrap (0%, 0.5 %, 0.75 %, and 1.5 %) determined by the volume of concrete. The compression behavior was obtained using uniaxial compression tests while the tensile behavior was obtained using splitting tensile tests. Laboratory testing of 12 cubic specimens and 12-cylinder specimens was conducted on the 28th day of curing. With the addition of waste steel scrap, it was found in the test results that the compressive strength increased by 26.8 % for 0.5 %, 30.7 % for 0.75 %, and reduced by 5.3 % for 1.5 % by volume of concrete. The splitting tensile strength increased by 11.2 % for 0.5 %, 5.8 % for 0.75 % and 2.5 % for 1.5 % by volume of concrete. The test outcomes showed that the modulus of elasticity and peak strain contains a remarkable increment with the increase in waste steel scrap volume. Compared with plain concrete, the strength properties of concrete with steel scrap were improved, however, with an increased amount of waste scrap, the workability of concrete was reduced.

Mechanical Performance and Environmental Assessment of Sustainable Concrete Reinforced with Recycled End-of-Life Tyre Fibres.

The presented research’s main objective was to develop the solution to the global problem of using steel waste obtained during rubber recovery during the tire recycling. A detailed comparative analysis of mechanical and physical features of the concrete composite with the addition of recycled steel fibres (RSF) in relation to the steel fibre concrete commonly used for industrial floors was conducted. A study was carried out using micro-computed tomography and the scanning electron microscope to determine the fibres’ characteristics, incl. the EDS spectrum. In order to designate the full performance of the physical and mechanical features of the novel composite, a wide range of tests was performed with particular emphasis on the determination of the tensile strength of the composite. This parameter appointed by tensile strength testing for splitting, residual tensile strength test (3-point test), and a wedge splitting test (WST), demonstrated the increase of tensile strength (vs unmodified concrete) by 43%, 30%, and 70% relevantly to the method. The indication of the reinforced composite’s fracture characteristics using the digital image correlation (DIC) method allowed to illustrate the map of deformation of the samples during WST. The novel composite was tested in reference to the circular economy concept and showed 31.3% lower energy consumption and 30.8% lower CO2 emissions than a commonly used fibre concrete.

Investigating flexural performance of waste tires steel fibers-reinforced cement-treated mixtures for sustainable composite pavements

In many parts of the world, the cement-treated base course material has been extensively used within composite pavements for enhancing the load-carrying capacity of pavements. However, its vulnerability to cracking under repetitive traffic loading, due to its brittle nature, significantly cuts off its lifespan and hence reducing the sustainability of composite pavements. To provide a solution to this problem, this study is aimed to investigate the flexural performance of cement-treated base (CTB) mixtures reinforced with the Waste Steel Fibers (WSF) extracted as a residual product from the scrap tires. The flexural performance is evaluated in terms of flexural fatigue and flexural strength. Moreover, the effect of steel fiber reinforcement on the dynamic modulus of the cement-treated base mixtures was also studied. The specimens for dynamic modulus were prepared by using a gyratory compactor to better simulate the traffic loading. Furthermore, the basic split tensile strength and unconfined compressive strength of WSF reinforced CTB mixtures were also studied. Lastly, important correlations were derived based on the results obtained in this study, to predict the flexural performance of CTB mixtures in terms of dynamic modulus and fatigue life by conducting basic split tensile strength tests and flexural strength tests. Based on the results, WSF reinforcement has noticeably enhanced tensile strength, dynamic modulus, flexural strength, and fatigue life of CTB mixtures. On the other hand, the variations in the compressive strength due to WSF reinforcement were trivial. Based on the results, the steel fibers content of 0.3% by volume of the wet compacted blend has shown more promising results than lower and higher WSF contents.