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Magnesium slag (MS) and fly ash (FA) are industrial wastes that must be utilized in a clean, effective, and massive method to avoid environmental pollution. In this study, the preparation of diopside-augite-based glass-ceramics was theoretically analyzed and experimentally conducted by disposal of MS and FA with chromium oxide (Cr 2 O 3) as a nucleating agent. The thermodynamics analysis first indicated that pyroxene could be the main crystal phase of the target glass-ceramics for the co-utilization of both wastes. The experimental results indicated that the main phase in prepared glass-ceramics samples was diopside ([Ca(Mg, Fe, Al)(Si, Al) 2 O 6 ], and the degree of glass network polymerization was enhanced with the FA in raw material increasing from 50 wt% to 65 wt%. Plus, the crystal size of the prepared glass-ceramics was gradually refined by increasing the FA. The optimized conditions were given as controlling nucleation at 790 °C for 2 h and crystallization at 929 °C for 2 h of the parent glass that derived from 40 wt% MS and 60 wt% FA as raw materials, 1 wt% Cr 2 O 3 as nucleating agent. The resulting glass-ceramics had excellent properties and chemical stability, such as a density of 3.11 g cm−3, bending strength of 101.98 MPa, acid resistance of 98.34 %, and alkali resistance of 99.53 %. This study provided a route to produce eco-friendly glass-ceramics material for architectural decoration by high-efficiency utilization of MS and FA. [ABSTRACT FROM AUTHOR]

The non-biodegradable Congo red (CR) dye which is widely used in textile industries has poses carcinogenic risks due to its complex reactions that may generate benzidine. Effective treatment of industrial effluent containing CR dye is imperative. This study assessed chitosan (Cs) and chitosan/fly ash (Cs/Fa) composites for biosorbing CR dye from synthetic textile wastewater. Fly ash varied in the range of (1:0.25–1:1) with chitosan to assess adsorption performance. Characterization techniques included FTIR, SEM, EDX, BET, and zeta potential analyses. Response surface methodology guided the determination of optimal variables. The study examined Cs and Cs/Fa dosage (A), time (B), and initial dye concentration (C) effects on CR removal. Incorporating fly ash substantially cut adsorption costs by 50% while enhancing dye removal up to 85% at pH 6. Improved acidic stability of chitosan (Cs/Fa 1:0.75) was notable. Chitosan (Cs) exhibited a high Congo red removal efficiency of 98% while the chitosan/fly ash (Cs/Fa) composites showed a substantial removal efficiency of 94%. Optimal conditions were 2 g L−1 of adsorbents, initial CR concentration of 40 mg L−1 for 120 min. Freundlich isotherm model best described adsorption behavior. Pseudo-second-order kinetics correlated significantly (R2 = 0.999). This study showed the potential of Cs and Cs/Fa bio-composites for effective textile wastewater treatment. [ABSTRACT FROM AUTHOR]

Industrial development has led to an increase in demand for friction materials, resulting in increasingly prominent environmental issues throughout their entire life cycle, and developing green and eco‐friendly brake friction materials has become a focus in the braking field. This paper explores the mechanical and tribological properties of fly ash (industrial waste) and sisal fiber (natural fiber) as eco‐friendly components to enhance brake friction materials. Four samples containing different ratios of fly ash and sisal fiber were prepared and tested with a variable‐speed friction testing machine. The results show that the eco‐friendly alternative combination can effectively improve the friction coefficient, and reduce friction fluctuations and thermal degradation, but the wear rate will also increase accordingly. In addition, the worn morphology reveals the formation of the contact platform and wear mechanism. A hybrid integration of analytic hierarchy process (AHP) and multi‐objective optimization by ratio analysis (MOORA) was used to weigh various evaluation indicators objectively and rank the samples. The sample with 8% fly ash and 6% sisal fiber exhibited the best comprehensive tribological performance. Highlights: Development of eco‐friendly brake friction composites with natural and waste additives.Investigation of the effect of the natural wastes' ratio on prepared composites' physical, mechanical, and tribological properties.Evaluation of brake friction composites with AHP‐MOORA.Sample S6F8 exhibits the best comprehensive tribological performance. [ABSTRACT FROM AUTHOR]

Expansive clays feature high compressibility and large swelling-shrinkage potential, which may cause significant damage to the infrastructures, including pavements. This study investigates the potential use of industrial waste ash generated from municipal solid waste incineration (MSWI) as a more sustainable treatment method to treat expansive soils compared to the use of conventional coal fly ash. A series of tests was conducted to study the mechanical, durability, and environmental performance of the MSWI fly ash in comparison with the coal fly ash. The study reveals that the compressive strength and resilient modulus of 20% MSWI fly ash treated sample increased to 0.86 MPa and 213 MPa respectively, depicting an increase of 150% and 240% of the control clay specimen. Results also indicate that MSWI treated expansive clay shows better performance during the soaked California bearing ratio (CBR) testings, moisture susceptibility and cyclic wetting–drying tests compared to coal fly ash treated samples. Microlevel investigations reveal that the influence of cation exchange is more decisive in the MSWI-treated clays due to the presence of higher Ca2+ ions, during the early stages, and the influence of hydration is stronger at the later stage of stabilisation. X-ray diffraction (XRD) results show that gismondine, albite, calcite, portlandite, andradite, and ettringite are the main crystalline phases formed during the stabilization. Heavy metal concentrations after the stabilisation are within the allowable limit defined by state regulations. Applying MSWI fly ash as a ground treatment for expansive clays can reduce the consumption of natural resources, promoting a "zero landfill" policy. [ABSTRACT FROM AUTHOR]

The current study examines the strength and transport properties of reclaimed asphalt pavement (RAP) inclusive pervious concrete (PC) pavement mixes containing various industrial and agricultural wastes such as silica fume (SF), fly ash (FA), and bagasse ash (BGA). Apart from a conventional PC mix (containing natural aggregates) and a 100% RAP inclusive PC mix, seven different mixes were developed by mixing 100% RAP aggregates with SF (5 and 10%), FA (10 and 15%), and BGA (5, 10, and 15%) as partial replacements for ordinary Portland cement. The above-mentioned PC pavement mixes were investigated for density, porosity, permeability, compressive strength, modulus of rupture, and abrasion resistance. The interconnected pore structure of conventional PC and RAP-PC pavement mixes was investigated using 2D image analysis and X-Ray microcomputed tomography. Based on the laboratory results, it can be stated that the inclusion of RAP significantly improves the transport properties of PC pavement mixes with increased porosity and permeability values. This was primarily due to a more interconnected pore matrix and lesser isolated voids in the RAP-PC pavement mix. The addition of SF could only improve the strength parameters (compressive strength and modulus of rupture) of the RAP-PC pavement mix. In contrast, BGA inclusion was observed to improve its transport properties (porosity and permeability). Furthermore, the inclusion of SF, FA, and BGA in a 100% RAP-PC mix improved abrasion resistance. When compared to the conventional PC pavement mix, incorporating RAP aggregates blended with SF, FA, and BGA can reduce the production cost of 1 m3 PC by 30–61% and lower CO2 emissions by 13–21%. However, considering the strength and transport property requirements of PC mixes, as well as the economic and environmental viability, the present investigation recommends using 5% SF, 10% FA, and 10% BGA in a 100% RAP-PC pavement mix. [ABSTRACT FROM AUTHOR]

As a result of firing pulverized coal in thermal power plants, enormous amounts of fly ash (FA) are produced as industrial waste. The release into the atmosphere and storage of this industrial waste remains one of the major environmental problems that threaten human health by contributing to air, water, and soil pollution. The recovery and reuse of FA in the construction industry is the only economic solution to the existing problem. In this study, the potential radiological risk caused by the usage of FA in concrete and cement production as a main component and its storage in landfill sites was evaluated for people and works by estimating radiological parameters (activity concentration and alpha index, annual effective doses, and the corresponding excess lifetime cancer risks) based on activity concentrations of terrestrial radionuclides in FA. Also, the radiological risk to the workers working in the FA landfill site was evaluated using the Residual Radioactivity Onsite 7.2 code. The average activity concentrations of terrestrial radionuclides in FA samples from the Tunçbilek lignite coal-fired thermal power plant at Kütahya province of Turkey were measured as 417, 156 and 454 Bq kg−1 for 226Ra, 232Th and 40K, respectively. When using up to 35% by mass of FA in cement and concrete, the average values of the radiological parameters revealed that they were within the recommended safety limits. However, code estimations showed that a regular worker in FA storage would be exposed to a total effective dose rate greater than 3 mSv y−1. [ABSTRACT FROM AUTHOR]

The electrodes of industrial electrostatic precipitators degrade as a result of two phenomena: corrosion and erosion. The first is chemical degradation by highly reactive compounds formed during combustion, in particular, during the incineration of municipal or industrial wastes or high-sulfur coal. The degradation intensity of electrostatic precipitator electrodes depends on the chemical composition of the exhaust gasses. High concentrations of chlorides, fluorides, or sulfur in the exhaust gasses cause strong corrosion of the electrostatic precipitator elements. The second mechanism is the erosion caused by solid particles conveyed by the exhaust gas stream due to their collision with the electrodes. In this study, the analysis of the degradation of electrodes of an electrostatic precipitator downstream of an industrial waste incinerator was carried out. The industrial wastes of unknown sources were subjected to thermal degradation in a rotary kiln. The aim of this study was to provide fundamental knowledge about the mechanisms of electrode degradation located on the surface of discharge electrodes of electrostatic precipitators during the combustion of industrial wastes. [ABSTRACT FROM AUTHOR]

This Study is focused on suitability of industrial wastes in cement stabilized soil. The investigation is based on Unconfined compressive strength (UCS) tests. Experimental work is carried out to compare the UCS of cement stabilized soil specimens with different proportion of industrial wastes like Iron ore tailing, Quarry dust, Fly ash and Bagasse ash. The mix proportion is designed such that clay content is maintained at 10.5% for fine grained soil and density of 17.5 kN/m³. It is observed that the mix comprising industrial wastes and fiber have improved the mechanical properties compared to cement stabilized soil. Fiber addition has improved post peak behavior of soil specimen. The Scanning Electron Microscopy (SEM) microstructure images depict soil particle flocculation, leading to an increase in compressive strength and Energy Dispersive X-ray Spectroscopy (EDS) studies suggest the use of industrial wastes with natural soil helps in strengthening of soil cement stabilization, as well as to minimize the environmental pollution. [ABSTRACT FROM AUTHOR]

Due to industrialization, soil heavy metal pollution is a growing concern, with humic substances (HS) playing a pivotal role in soil passivation. To address the long duration of the compost humification problem, coal fly ash (CFA) in situ catalyzes the rapid pyrolysis of the cotton stalk (CS) to produce HS to address Cd passivation. Results indicate that the highest yield of humic acid (HA) (8.42%) and fulvic acid (FA) (1.36%) is obtained when the CS to CFA mass ratio is 1:0.5, at 275 ℃ for 120 min. Further study reveals that CFA catalysis CS humification, through the creation of alkaline pyrolysis conditions, Fe2O3 can stimulate the protein and the decomposition of hemicellulose in CS, and then, through the Maillard and Sugar-amine condensation reaction synthesis HA and FA. Applying HS-CS&CFA in Cd-contaminated soil demonstrates a 26.69% reduction in exchangeable Cd within 30 days by chemical complexation. Excellent maize growth effects and environmental benefits of HS products are the prerequisites for subsequent engineering applications. Similar industrial solid wastes, such as steel slag and red mud, rich in Fe2O3, can be explored to identify their catalytic humification effect. It could provide a novel and effective way for industrial solid wastes to be recycled for biomass humification and widely applied in remediating Cd-contaminated agricultural soil. [ABSTRACT FROM AUTHOR]

The utilization of industrial solid waste in mines is an important approach to resource utilization. The backfill material in mines is mainly composed of solid waste, which plays a supporting role. The excitation effect of lime on phosphogypsum and fly ash in backfill was studied in this paper. The macroscopic and microscopic characteristics of the backfill material were tested using uniaxial compression, nuclear magnetic resonance, scanning electron microscopy, and electrochemical techniques, and a relationship model was established between them. Furthermore, the influence of industrial solid waste on the properties of the backfill material under the action of lime and the hydration mechanism between different industrial solid wastes were studied. The results show that (1) under the action of lime, fly ash reacts with lime to produce C-S-H and C-A-H, and then C-A-H reacts with phosphogypsum to produce AFt. (2) The excess phosphogypsum also fills the pores. Therefore, 1.8% lime reduces the porosity of the backfill by 17.88% and increases the strength by 21.57%. (3) The cross-scale relationship shows that strength is inversely proportional to each type of pore content and fractal dimension, and it logarithmically increases with impedance at different frequencies. The lower the frequency, the stronger the relationship is. (4) This study indicates that industrial solid waste is a suitable cement replacement. [ABSTRACT FROM AUTHOR]

Replacement of industrial byproducts as the main components of concrete has gained the attention toward the environment in reducing the raw material consumption. Fly ash (FA) cenosphere is one such industrial product used in the concrete as a partial or full replacement of fine aggregate, which can be able to use for non‐structural applications. Whereas for structural applications, reinforcement in the concrete and their bond behavior is an essential factor that influences its structural behavior. Hence, this study explores the bond behavior of plain and deformed rebar, 10 and 12 mm, respectively, in concrete containing 0%, 25%, 50%, 75%, and 100% FA cenosphere as fine aggregate. A pull‐out test is performed to study the bond behavior experimentally and the results show that the bond strength decreases with increase in the diameter of the rebar irrespective of concrete's compressive strength. The deformed rebar showed a better performance than the plain rebar with an average bond stress of nearly 60%. Finite element analysis has been performed using ANSYS‐ 2022R2 to validate the experimental results with simulated results in which the error percentage is in line with good results. [ABSTRACT FROM AUTHOR]

The intricate composition of wastewater impedes the recycling of agricultural and industrial effluents. This study aims to investigate the potential of sisal leaf wastewater (SLW), both water-treated (WTSLW) and alkali-treated (ATSLW), as a substitute for the alkali activator (NaOH solution) in the production of slag-powder- and fly-ash-based composites, with a focus on the effects of WTSLW substitution ratios and sisal leaf soaking durations. Initially, the fresh properties were assessed including electrical conductivity and fluidity. A further analysis was conducted on the influence of both WTSLW and ATSLW on drying shrinkage, density, and mechanical strength, including flexural and compressive measures. Microstructural features were characterized using SEM and CT imaging, while XRD patterns and FTIR spectra were employed to dissect the influence of WTSLW substitution on the composite's products. The results show that incorporating 14 wt% WTSLW into the composite enhances 90-day flexural and compressive strengths by 34.8% and 13.2%, respectively, while WTSLW curtails drying shrinkage. Conversely, ATSLW increases porosity and decreases density. Organic constituents in both WTSLW and ATSLW encapsulated in the alkaline matrix fail to modify the composites' chemical composition. These outcomes underscore the potential for sustainable construction materials through the integrated recycling of plant wastewater and solid by-products. [ABSTRACT FROM AUTHOR]

There are many environmental problems caused by factory waste. Sugar factory waste, in the form of bagasse ash, and PLTU factory waste, in the form of fly ash, are currently in the spotlight of science studies. This study used waste bagasse and fly ash to substitute Portland cement as the main ingredients for mortar. Baggash and fly ash waste were collected, processed, and then used to replace cement by up to 40% to determine to what extent they could be used in brick masonry work, wall plastering, and masonry paste. Experimental tests were carried out on mortar cube samples measuring 5×5×5 cm, comparing four types of samples consisting of Portland cement, bagasse ash, and fly ash. The compressive strength results were obtained after 28 days. Normal Mortar (MN=11.75 MPa) had higher compressive strength than the substitute mortar types MA (3.23 MPa), MB (3.09 MPa), and MC (2.98) MPa. According to SNI 6882- 2014, MA, MB, and MC mortars can be used as O-type mortar (2.4 MPa). Therefore, they can be applied to wall plastering or walls not bearing loads. [ABSTRACT FROM AUTHOR]

In the context of green and low-carbon materials development, the influence of replacing cement with circulating fluidised bed fly ash (CFBFA) on the expansion properties of paste under different curing conditions was first systematically investigated. Then, self-compacting concretes (SCCs) with recycled aggregate (RA) and CFBFA were prepared for filling steel tubes. The experimental results showed that, because of its unique physicochemical properties, the incorporation of CFBFA significantly increased the water requirement needed to achieve standard consistency of the paste and the pore structure was optimised by a reduction in the number of large pores due to the formation of more expansion components (ettringite, gypsum and portlandite are the main expansive products of CFBFA–cement paste). The influence of factors such as curing condition, age and CFBFA on the expansion effect was notable. With a 40% CFBFA content, the RA SCC in the steel tube showed an expansion of 41 μm/m, while the 28-day compressive strength reached 48.9 MPa. [ABSTRACT FROM AUTHOR]

Cold mix asphalt (CMA) technology is the most sustainable technology (green) available for the construction of flexible pavement to date, owing to the lower production temperatures involved. The present research investigates different fillers such as cement, fly ash (FA), and Stabil-road (SR) in different proportions ranging from 0 to 3% (1% increment). One control CMA with 1.5% water content and 6.6%asphalt residue and nine mixes with variable filler contents were prepared and tested according to the standards. The prepared mixes were tested and analyzed for mechanical properties namely Marshall stability, indirect tensile strength, resilient modulus (Mr), and abrasion loss. The stability of the CMA with 3% cement was 22% higher compared to the control CMA. Improvements in strength were observed with the inclusion of filler in the cold mix. The cold mix bituminous macadam (CMBM) is used for low-volume roads with mineral fillers, and it is a type of CMA, but using FA and SR, the strength and workability of the CMBM mix can be improved, and the mineral filler can be replaced by industrial waste. Significant reductions in production temperature and improved service life are some of the study's outcomes. It is a significant study because it reduces the asphalt production temperature and increases the pavement service life. It reduces energy loss during the construction of road pavement. Furthermore, the mechanical properties of the designed CMA depend on the mixing of aggregates, prewetting water content, emulsion, curing time, and pulse repetition periods. [ABSTRACT FROM AUTHOR]

The environmental impact of wastewater discharged from the textile dyeing industry has a significant challenge and influence on aquatic ecosystems and human health if not properly managed. This study aimed to develop a novel cross-linked chitosan composite, denoted as chitosan/fly ash/polyvinyl alcohol (Ch/FA/PVA), as a bio-adsorbent for removing Congo Red (CR) textile dye from industrial wastewater. The synthesis involved the incorporation of FA into the chitosan matrix at various ratios to optimize the process. A specifically tailored composite, Ch/FA0.75/PVA, exhibited superior performance with a remarkable 99.7% CR removal under optimum conditions: adsorbent dose (0.9 g/l), contact time (50 min), and dye concentration (40 mg/l). The characterization of Ch/FA0.75/PVA through SEM–EDX, BET, FTIR, and pHzpc confirmed its suitability for adsorption. Employing Box–Behnken design and analysis of variance (ANOVA) facilitated the optimization of key adsorption variables. The Freundlich model described the adsorption equilibrium, indicating a maximum adsorption capacity of 263.15 mg/g for CR dye. The pseudo-second-order model demonstrated favorable kinetics. The study was scaled up to the practical application of Ch/FA0.75/PVA in a pilot plant for industrial wastewater treatment, revealing substantial removal percentages for dye, color, COD, BOD5 and TDS. This comprehensive approach highlights the promising efficacy of Ch/FA0.75/PVA in addressing environmental concerns associated with textile dye wastewater. [ABSTRACT FROM AUTHOR]

A steam jet mill (SJM), which employs industrial waste heat steam as a gas source, is a widely utilized apparatus for the pulverization of fly ash. To achieve elevated single-machine grinding capacity, efficiency improvement research based on structural optimization should be conducted. In this study, numerical simulations and industrial experiments are carried out on SJMs equipped with three and six nozzles (hereinafter referred to as N3 and N6, respectively) to study the influence of nozzle quantity on the flow field and grinding efficiency. The numerical simulation results indicate that, under the N3 structure, particles can achieve a higher impact velocity in the comminution area and improve the kinetic energy of a single impact. In the conveying area, the airflow diffusion is better, resulting in an upward flow field that is more uniform. The classification area shows an increase in the uniformity of the flow field and a significant reduction in the local vortex structure, which is beneficial for accurate particle classification. In the interim, industrial experiments demonstrate that the N3 structure can markedly enhance the processing capacity and energy efficiency of the system. The smaller the feed particle size, the more pronounced the efficiency improvement. [ABSTRACT FROM AUTHOR]

The global strategy to reduce waste production implies development of recycling technologies and conversion of various waste into value‐added products. Fly ash is an industrial waste produced in a large amount. It comprised an aluminosilicate cenosphere, which seems perspective as a support for heterogeneous catalysts. Here we report the preparation and application of heterogeneous silver nanocatalysts deposited on cenosphere in the epoxidation reaction, a relevant process for preparation of valuable organic precursors and target chemicals. Reductive wet deposition method yields Ag nano‐dispersed coating of improved quality represented by Ag particles of about 2.7 nm on the surface of the microspheres size of 50–250 microns for catalytic synthesis of styrene‐oxide. The 0.1 mmol/g Ag/cenosphere provided best catalytic results with threefold excess of tret‐butyl hydroperoxide in acetonitrile at 80 °C. Comparison of fly ash cenosphere with other supports suggests that low porosity of microspherical support allows for an easier access of reagents to active sites of the catalyst and significantly increases the yield of epoxide and selectivity of the reaction. [ABSTRACT FROM AUTHOR]

The utilization of CO2 mineralization fly ash (F) and coal gangue (G) technology is proposed in this research work to prepare underground backfilling materials. The test process can be divided into pre-treatment and post-treatment stages. In the pre-treatment stage, a sealed stirring vessel is used to conduct CO2 wet mineralization. The ratios of F and G were selected as follows: 20%:60% (F2G6), 30%:50% (F3G5), 40%:40% (F4G4), 50%:30% (F5G3), and 60%:20% (F6G2). The ratios were prepared into Φ50 mm × 100 mm cylindrical samples, with curing durations of 3 d, 7 d, 14 d, and 28 d. In the post-processing stage, the SANS microcomputer-controlled electronic universal testing machine and FLIR A615 infrared thermal imager were used to carry out uniaxial loading and temperature detection, respectively. The unconfined compressive strength (UCS), X-ray diffraction (XRD), average infrared radiation temperature (AIRT), variance of original infrared image temperature (VOIIT), and variance of successive minus infrared image temperature (VSMIT) of the samples were compared and analyzed. The results indicated that when curing reaches 14 d, the strength approaches its peak, with minimal changes in strength over a delayed period; furthermore, as the ratio of F to G continues to increase, the mineralization effect gradually strengthens, reaching its optimum level at a ratio of 5:3. However, when the ratio exceeds 5:3, signs of deteriorating mineralization effect start to appear. During the loading process, the AIRT of the mineralized samples showed a continuous increase, but the VOIIT and VSMIT of the mineralized sample both exhibited significant fluctuations or rapid increases during damage rupture. Moreover, the rise in the AIRT value was found to be linked to the increase in the ratio of F to G. This indicates that F has a higher thermal–mechanical conversion efficiency compared to G, so the temperature change will be greater during the loading process. The drastic changes in the VOIIT and VSMIT indicate that they can be used as sensitive response indicators for sample rupture, and can predict and warn of damage rupture in mineralized samples. Research work can provide practical guidance and reference for underground backfilling of CO2 mineralization industrial waste. [ABSTRACT FROM AUTHOR]

The proposed research work is to develop the brick by incorporating steel industry industrial waste to achieve sustainable environment. Aluminium dross (AD) is the one of the major waste produced during aluminium ingots production. Particle size and chemical compositions of aluminium dross are analysed using Scanning Electron Microscopy (SEM). To effectively utilise the aluminium dross, five mix composition of bricks were produced to determine the influence of AD on mechanical properties of bricks such as the compressive strength, water absorption, efflorescence and bulk density. Mix B gives the maximum compressive strength of 11.54 N/mm2, water absorption of 5.6% and bulk density of 1658.4 kg/m3 for the mix of 5% dross. Analysis of variance (ANOVA) is employed to analyse the influence of dross and fly ash concentrations on the quadratic model. [ABSTRACT FROM AUTHOR]

CO2 mineralization plays a critical role in the storage and utilization of CO2. Coal fly ash (CFA) and red mud (RM) are widely utilized as CO2 mineralizers. However, the inert calcium species in CFA limit its carbonation capacity, meanwhile the substantial Ca2+ releasing of RM is hindered by a covering layer of calcium carbonate. In this study, CO2 mineralization in a composite system of CFA and RM was investigated to enhance the carbonation capacity. Multiple analyzers were employed to characterize the raw materials and resulting mineralization products. The results demonstrated that a synergistic effect existed in the composite system of CFA and RM, resulting in improving CO2 mineralization rate and efficiency. The produced calcium carbonate was ectopically attached the surface of CFA in the composite system, thus slowing down its coverage on the surface of RM. This phenomenon facilitated further releasing Ca2+ from the internal RM, thereby enhancing CO2 mineralization efficiency. Meanwhile, the inclusion of RM significantly improved the alkalinity of the composite system, which not only promoted the dissolution of Ca2+ of the inert CaSO4(H2O)2 in CFA, but also accelerated CO2 mineralization rate. The investigation would be beneficial to CO2 mineralization using industrial solid wastes. [ABSTRACT FROM AUTHOR]

The pre-eminence of concrete as the constitutional material used for rigid pavement construction has emanated through the millennia thereby amplifying the concern associated with its adverse effect on the environment. In this context, geopolymer concrete not only proposes a sustainable solution but also addresses the problems associated with extensive industrial waste generation and its imprudent disposal. This study aims to highlight the relevance of fly ash (FA) and red mud (RM) as geopolymer synthesizing source materials for pavement quality concrete (PQC). Investigations were designed to study the effect of varying replacement levels of FA (10%, 20%, 30%, and 40%) with RM in conjunction with different concentrations of sodium hydroxide in terms of molarity (10 M, 12 M, 14 M). The specimens subjected to ambient curing and oven curing at 60 °C were tested for compressive strength, flexural strength, and split tensile strength. Results portray that in the case of ambient cured FA-RM specimens, the highest compressive strength and flexural strength that could be achieved were 31.5 MPa and 4.32 MPa, respectively. Thereby, indicating inadequate strength development as per the requirements of PQC, even at a higher concentration of sodium hydroxide. Moreover, replacing FA with RM is mostly not effective at replacement values greater than 20% in both compression and tension. Furthermore, a defined study for assessing durability properties was also conducted by immersing the specimens in a 5% sulfuric acid solution. 11.46% and 7.25% reduction in compressive strength of control mixes was observed for specimens corresponding to 10 M and 14 M respectively, thereby substantiating decreased strength loss at higher molarity. [ABSTRACT FROM AUTHOR]

Fouling in convective parts of boilers is typical of the deposition of solid particles and condensable inorganic vapours. Particle sticking is caused mainly by gravity, adhesion, or the presence of a sticky liquid film of condensed vapours. Aside from the local conditions, particle properties and size determine whether they are sticking on the surface. This work focuses on simulations of particulate matter fouling of cooled tubes by fly ash produced by the combustion of industrial waste and sewage sludge mixture. Boundary conditions including the flue gas and particle flow rate are derived from combustion tests. Particle properties and size distribution are obtained from literature. The goal is to provide a basis for further modelling of the development of large deposits in tube bundles observed during a test on the experimental facility. Neither the combustion nor fly ash development is modelled. Their transport and deposition are simulated. Fixed boundary conditions are set for both the particulate and gas phases. The influence of already deposited particles on the surface mechanical properties and roughness is included to capture their deposition. The fly ash particles are considered completely solidified, considering the low flue gas temperatures on the facility inlet. [ABSTRACT FROM AUTHOR]

The present study directs the need for the development of an economical composite mix comprised locally available soil and industrial waste which satisfy the design parameters of the municipal solid waste (MSW) landfill. The local soil, bentonite, and fly ash mixtures are mixed in different proportions to evaluate the geotechnical and microstructural characteristics for suggesting an optimum composite mix that fulfills the design parameters of landfill liners. The curing periods of different mixes are also considered while evaluating the unconfined compressive strength (UCS) characteristics. The microstructure of the mixtures is examined using advanced imaging techniques, including X-ray diffraction (XRD), scanning electron microscopy (SEM), and energy-dispersive X-ray spectroscopy (EDAX) to gain insights into the changes at the microscale level due to the inclusion of fly ash. It is observed that soil-bentonite-fly ash composite mix in a ratio of 65:15:20 aligns with the optimal design characteristics required for a landfill liner. Notably, for this composite mix, both liquid limit (LL) and plastic limit (PL) show a significant increase of 48.57% and 32.33% respectively, while the optimum moisture content (OMC) rises by 11.25%. Conversely, maximum dry density (MDD) experiences an 8.79% decrease. Moreover, the free swell index (FSI) escalates by 113%, whereas hydraulic conductivity (HC) records a substantial reduction of 96.04%. Moreover, the UCS exhibited a notable increase of 209% after a 28-day curing period. The highest strength is achieved initially by soil mixed with 20% fly ash, followed by a blend containing 15% bentonite. Therefore, proper fly ash content in filler and other binder materials is an effective and sustainable approach that not only solves the disposal issue but also enhances the material's engineering characteristics, justifying its suitability to be used as a landfill liner. [ABSTRACT FROM AUTHOR]

This study focuses on using activated fly ash to preparate silica aerogel by the acid solution–alkali leaching method and ambient pressure drying. Additionally, to improve the performance of silica aerogel, C6H16O3Si (KH-570) and CH3Si(CH3O)3 (MTMS) modifiers were used. Finally, this paper investigated the factors affecting the desilication rate of fly ash and analyzed the structure and performance of silica aerogel. The experimental results show that: (1) The factors affecting the desilication rate are ranked as follows: hydrochloric acid concentration > solid–liquid ratio > reaction temperature > reaction time. (2) KH-570 showed the best performance, and when the volume ratio of the silica solution to it was 10:1, the density of silica aerogel reached a minimum of 183 mg/cm3. (3) The optimal process conditions are a hydrochloric acid concentration of 20 wt%, a solid–liquid ratio of 1:4, a reaction time of two hours, and a reaction temperature of 100 °C. (4) The optimal performance parameters of silica aerogel were the thermal conductivity, specific surface area, pore volume, average pore size, and contact angle values, with 0.0421 W·(m·K)−1, 487.9 m2·g−1, 1.107 cm3·g−1, 9.075 nm, and 123°, respectively. This study not only achieves the high-value utilization of fly ash, but also facilitates the effective recovery and utilization of industrial waste. [ABSTRACT FROM AUTHOR]

The huge demand for sand and gravel resources in road engineering construction leads to excessive consumption of resources and environmental damage. Recycling waste concrete and industrial solid waste as a road material is a promising alternative. In order to explore the application of these solid wastes in the road base, this paper studies the effect of adding lithium slag activated by an alkaline activator, fly ash (FA) and a combination of the two on the compressive strength, splitting strength and shrinkage performance of recycled cement-stabilized macadam mixture (RCSM). The optimum content of recycled aggregate (RA), alkali-activated lithium slag (AALS) and FA in composite-improved RCSM was optimized using a response surface method (Box–Behnken), and the microscopic characteristics of the mixture were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results show that the optimum dosage of AALS, FA and RA determined by the response surface method is 15%, 10% and 40%, respectively. Compared with the cement-stabilized macadam mixture (CSM) with 40% RA, the 28 d compressive strength and 28 d splitting strength of the composite-improved RCSM are increased by 26.8% and 22.9%, respectively, and the dry shrinkage coefficient and average temperature shrinkage coefficient are decreased by 25.8% and 14.8%, respectively. Microscopic tests show that AALS and FA participate in the hydration reaction, generate more hydrated silicate (C-S-H) and ettringite (AFt), refine pores, effectively improve the performance of the internal interface transition zone of the mixture, make the microstructure of the mixture denser, and improve the strength and shrinkage performance of RCSM. This study provides technical support for the reuse of resources and the sustainable development of road construction. [ABSTRACT FROM AUTHOR]

In the context of ongoing rapid industrialization, the increasing deposition of industrial waste has arisen as a persistent global challenge, necessitating immediate attention and subsequent implementation of sustainable remedies. This study convenes on the efficacy of industrial wastes, namely fly ash and ground granulated blast furnace slag, as geopolymer concrete synthesizers in conjunction with the incorporation of reclaimed asphalt pavement (RAP) aggregates as a replacement for natural coarse aggregates varying over 25% to 100%. Under 7 days of ambient curing, employing 14M NaOH and a 50% RAP replacement, the mix achieved significant strengths of 41.80 MPa in compression and 4.72 MPa in flexure, affirming its suitability for pavement quality concrete (PQC). Through this study, the phenomenon of efflorescence could also be explored, which was particularly significant during the winter seasons. Furthermore, the declining coefficient of determination (R2) with the rise in RAP, observed in the correlation between compressive strength and ultrasonic pulse velocity (USPV), likely signified increased variability in the mixture at higher replacement levels. Assessment of long-term performance in terms of resistance to surface abrasion established the mix as durable, depicting minimal depth of wear (0.081 mm). Furthermore, results of the rapid chloride penetration test (RCPT) demonstrated that the presence of adhered asphalt in RAP aggregates reduces porosity and enhances resistance. Microstructural study was additionally conducted to comprehend the importance of adhered asphalt in impeding crack propagation. ANOVA established a highly significant relationship between the interaction of curing age and RAP fractions with the strength characteristics of the mix. [ABSTRACT FROM AUTHOR]

Warm mix asphalt mixtures became attractive paving mixes by reducing the production temperature to around 25–40 °C as compared to that of conventional hot mix asphalt (HMA). This study aims to evaluate the warm mix asphalt (WMA) using wax-based additives by incorporating two types of industrial wastes. The potential application of low calcium fly ash (FA), i.e. class F type and marble dust (MD), has been evaluated by varying different percentage. The cylindrical samples were prepared and assessed for moisture susceptibility by being subjected to Marshall stability, retained Marshall stability (RMS), indirect tensile strength (ITS) and tensile strength ratio (TSR) tests. Furthermore, the samples were also evaluated for finding the refusal density, Cantabro loss and the rutting performance. A scanning electron microscope (SEM) was also used to evaluate the size and microstructure of the filler particles. The results revealed that the inclusion of fillers into mixes had significant improvement in the mechanical properties and lowered the rutting value with FA and MD addition. The warm mix additive and fillers used were also useful in reducing the binder content of the mixes. The mixing temperature was found to be in the range of 120–130 °C using the warm mix additive. The optimum usage of FA and MD can be up to 5% based on the evaluation. The statistical results reported that there was a significant difference between FA-based and MD-based WMA. [ABSTRACT FROM AUTHOR]

Engineered geopolymer composites (EGC) have emerged as a more environmentally friendly alternative to conventional engineered cementitious composites (ECC). These composites offer high mechanical and durability features. However, there is a lack of research on EGC, particularly with basic oxygen furnace (BOF) slag as a precursor and iron ore tailings (IOT) as a partial replacement to fine aggregate. Despite their effectiveness as industrial waste products in conventional concrete, this study aimed to determine the optimal compositions of fly ash (FA), steel fibres (SF), and IOT by varying their percentages. Overall, 150 mix combinations were tested, including six binder combinations, five combinations of fine aggregates, and five percentage variations in SF. Finally, one optimum mix was selected for each binder combination, based on the ultimate compressive strength values corresponding to the six optimal mixes. The compressive strengths of all the mixes were evaluated at both 7 and 28 days of curing, involving three replicate samples after oven curing (initial 24 h) followed by subsequent ambient curing until their respective ages. The highest observed compressive strength after 28 days was 41.77 MPa for 50 mm cubes. This strength was achieved with a composition of 60% FA, 1.5% SF, and 45% IOT. An increase in IOT percentage led to a nearly linear increase in strength, while the strength peaked at 1.5% for steel fibres. The addition of BOF slag significantly enhanced the compressive strength compared to mixes with full FA. A 40% fly ash replacement with BOF slag resulted in an average strength that was 39% higher than the combination with 100% fly ash. However, the strength growth decreased after a 10% replacement. Analysis of variance was conducted using the design of experiments methodology to determine the significance of the parameters and their interactions. All three independent parameters were found to be statistically significant, while their interactions were not. Utilizing Taguchi's analysis method with the L25 orthogonal array, it was concluded that IOT percentage was the most influential parameter. [ABSTRACT FROM AUTHOR]

AMD (acid mine drainage) with low pH and high content of heavy metals is a serious environmental problem in mining activities. Proper AMD management is crucial to ensure compliance with the standards of environmental quality before allowing the flow to the public water system. The objective of this study was to assess the efficacy of increasing pH and decreasing Fe alongside the concentrations of Mn in AMD with the addition of coal fly ash (CFA) and empty fruit bunch of oil palm (EFBOP). A total of four treatments, namely: (1) control (soil without treatment), (2) soil + EFBOP, (3) soil + CFA, and (4) soil + EFBOP + CFA were tested for the ability to improve AMD quality in a batch reactor experiment for 90 days. Weekly observations were carried out for pH, Fe, and Mn concentrations during the experiment, where part of AMD in the reactor was drained and replaced with fresh ones. The results showed that single treatment of EFBOP or CFA caused a pH increase at 2.8 to 5.1-5.4 and 6.3-6.8, respectively. Furthermore, a greater increase occurred from 2.8 to 7.0-7.8 when EFBOP was combined with CFA application. This combination also showed a greater reduction in the concentrations of Fe and Mn compared to the single treatment of EFBOP or CFA. The increase in pH and decrease in Fe alongside the Mn concentrations began in the 3rd week, and this effect was stable during the 90 days of the experiment. The results underscore the potential of EFBOP and CFA as agricultural and industrial wastes in long-term AMD management. [ABSTRACT FROM AUTHOR]

The mining operation is a challenging field for human development. Deep underground mining has increased as a result of the lack of economic minerals close to the surface of the ground. Mining companies are now thinking of backfilling mine wastes to prevent mine collapse during later and deeper extraction stages due to safety and environmental concerns. The production of waste products (for example, fly ash, slag, and tailings) during the processing of minerals, the production of electricity, and the production of metals is tremendous. There is a wealth of information available on employing fly ash, slag, and mine tailings as a partial substitute for cement, as well as for paste backfilling. Nevertheless, a thorough analysis of the use of industrial waste and mining tailings as mine backfill is mostly absent. This article offers a grave evaluation of the use of mine and industrial. Geotechnical characteristics, backfill material features, and issues relating to strength prediction are all examined. In addition to the aforementioned, the effects of substitute binders, such as industrial waste, are considered when modifying paste backfills utilizing admixture. The paper finished with future paths for mine paste backfilling study, specifically utilizing ordinary and non-natural essences for primary strength growth. Hence, continued use of such engineering waste supplies for mill paste backfilling might benefit from this research. [ABSTRACT FROM AUTHOR]

Integrating waste and industrial by-products into concrete is an alternative way to reduce global cement consumption, enhancing its eco-friendliness. In this context, residues with fly ash have been increasingly utilised. Considering the vulnerability of concrete with fly ash to carbonation and, at the same time, its high resistance to chlorides, it is important to investigate the behaviour of these concretes under their combined actions. For this purpose, an experimental investigation was conducted, studying mortar and concrete specimens with 40% replacement of cement with fly ash. These specimens were subjected to a combination of actions (Cl− and CO2) in two phases: initially through immersion and drying tests, and subsequently through a combination of accelerated tests. Concerning the chloride impact study, free and total chloride profiles were studied. Concerning the impact of carbonation, colourimetric and chemical tests were used. The results demonstrate a significant influence of combined action not only on chloride penetration in cement-based materials with fly ash but also on the development of a carbonation front. Exposure of cement-based materials with fly ash to environments with high Cl− and CO2 content sequentially may lead, on the one hand, to an increase in carbonation resistance. However, on the other hand, it may result in a substantial reduction in chloride penetration resistance. [ABSTRACT FROM AUTHOR]

Developing of green construction and reducing CO2 emissions in the environment is a priority for industry in the coming years. Recycling fly ash in the concrete industry is a well-known way to reduce environmental impact. Aside from this benefit, there are numerous other positive effects of incorporating fly ash into concrete; however, in this research, the objective is to replace cement with a different percentage of non-class fly ash with high CaO, more than 42%. The analyzed variables are non-class fly ash properties, the effect of fly ash presence on the main properties of concrete and examining the optimum of non-class fly ash in ordinary concrete C-25/30 and high-performance concrete C-50/60. All investigations took place in the laboratory by producing 24 different mix designs and more than 1000 specimens to examine: consistency, setting time, shrinkage, and compressive strength in the short and long terms of curing. Recycling industrial waste in new construction, especially fly ash because of its non-uniform properties, still has some obstacles and is not a practical issue, but the future must be environmentally friendly, and this research proves that the objective of producing sustainable ordinary and high-performance concrete was achieved by replacing 40% of cement with non-class high CaO content fly ash. [ABSTRACT FROM AUTHOR]

Wastewater discharges from industrial processes typically include elevated concentrations of contaminants, which largely consist of potentially harmful chemicals such as heavy metals. These contaminants are characterized by their slow rate of decomposition. Hence, the removal of these metallic ions from effluents poses a challenge. Among different treatments, the adsorption approach has considerable potential due to its ability to effectively eliminate both soluble and insoluble pollutants from effluent, even at lower levels of concentration. Of various wastes, fly ash (FA) material has been the subject of attention because it is abundant, has favorable qualities, and contains a high percentage of minerals. This review investigates multiple facets, with a specific focus on the application of FA, an industrial byproduct, as an adsorbent in removing heavy metals. A comprehensive examination was conducted on a range of concerns pertaining to the pollution caused by metallic ions, including the underlying causes, levels of contamination, health implications of heavy metals, and removal methods. Multiple factors were found to affect the adsorption process. Of all the factors, the pH value considerably influences the elimination of heavy metals. An acidic pH range of 2.5–4.5 was found to be optimal for achieving the highest possible elimination of As(V), Cu(II), Hg(II), and Cr(VI). The latter elimination rate reached 89% at the optimal pH level. Most heavy metals' adsorption isotherms conformed to the Langmuir or Freundlich models, while the pseudo-second-order kinetics provided a satisfactory match for their removal. Using a raw FA, adsorption capacities were achieved in the removal of metallic ions, Ni(II), Pb(II), and Cr(VI), that ranged from 14.0 to 23.9 mg g−1. Meanwhile, the FA-zeolite showed a remarkable capacity to adsorb ions Mn(II), Ni(II), Cd(II), Cu(II), and Pb(II), with values ranging from about 31 to 66 mg g−1. The cost analysis showed that the treatment of FA is economically advantageous and may result in significant cost reductions in comparison to commercial adsorbents. In summary, FA is an inexpensive waste material with potential for water treatment applications and several other purposes due to its excellent chemical and mineralogical composition. [ABSTRACT FROM AUTHOR]

Conventional cement concrete has surfaced as a major construction material with considerable global warming potential. Alternatively, a fly ash (FA) ground-granulated blast furnace slag (GGBS)-based alkali-activated concrete is introduced to attain the goal of net zero emission and reduce the environmental impacts. In this study fixed proportions of concrete mixes matching with a designated strength of plain cement concrete mix have been determined. In addition to this, an ambient curing condition has been integrated that will be helpful for practical implementation in large-scale construction. Sodium silicate and sodium hydroxide were used as alkaline activator solutions to activate the FA and GGBS. The alkali activator reciprocity, i.e. Na2SiO3/NaOH (NS/NH), was set at 2.5. For various combinations of FA and GGBS, the main parameters considered in this study were molarity of sodium hydroxide and alkaline solution/binder ratio. The variation implemented in this experimentation includes: proportions of FA and GGBS (80–20, 75–25, 70–30, 65–35, 60–40, 55–45 and 50–50) and molarity of NaOH (10, 12, 14 M). Results concluded that the FA–GGBS-based alkali-activated concrete exhibits better performance as compared to conventional concrete. Furthermore, X-ray diffraction, Fourier transform infrared spectrography, scanning electron microscopy and energy-dispersive X-ray are carried out to investigate the behaviour of microstructure of GPC. Life-cycle impact category values have also been estimated considering all possible construction scenarios. [ABSTRACT FROM AUTHOR]

Development of an efficient membrane from waste resources has been receiving growing interest. The utilization of industrial waste coal fly ash (CFA) for the preparation of SiC based tubular membrane has reduced the raw material cost and sintering temperature, and hence beneficial in both economic and environmental points. In the present work, tubular membrane was prepared by extrusion of ceramic paste formulated using SiC powder, CFA, suitable dispersant, plasticizer and additives. The extruded green body was dried and then sintered at 850°C. The membrane was characterized by measuring porosity, morphology by scanning electron microscopy, linear shrinkage, mechanical strength. The membrane performance was evaluated using synthetically prepared oil-water emulsion, turbid water, kitchen wastewater and industrial wastewater. The membrane was found to remove 93-95% of oil depending on the oil concentration in the feed water. The oil rejection potential of the membrane was compared with other membranes reported in the literature and the results indicated that the membrane prepared in this study had a strong potential applications in wastewater treatment. [ABSTRACT FROM AUTHOR]

High-strength cement-free geopolymer concrete with 62.9 MPa (after 28 curing days) was experimentally produced from blast furnace slag, recycled concrete, and metakaolin as alumina-silicate binders as well as silica fume as silica-rich ultra-fine powder. Combining slag with metakaolin and silica fume allowed to increase its proportion up to 58.1 wt. %, without affecting shrinkage and hardness. Residual concrete from demolition was also used for making the geopolymer concrete as coarse aggregate as well as alumina-silicate binder together with fly ash, but not with granulated slag, metakaolin, and silica fume, this constituting the paper originality. [ABSTRACT FROM AUTHOR]

Complex dyes have an adverse impact on the environment since they have a high aqueous solubility and are very challenging to be removed using conventional approaches. A series of batch tests were performed to determine the optimum parameters for the direct blue 78 dye adsorption process as a function of chemically treated coal fly ash (TCFA) Effect of fly ash dose, contact time and dye initial concentration were studied using an industrial wastewater. A pilot plant, consisting of three stages; mixing, sedimentation and filtration was designed and implemented to investigate the ability of TCFA to remove COD, BOD5, TDS and TSS from textile wastewater under optimal conditions. A series of fly ash physico-chemical analysis including particles size analysis, zeta potential, XRD, EDX, BET, SEM and FTIR were investigated. The results showed that the particles size and zeta potential for raw coal fly ash were 1.2 µm and −20.70 mv. Chemical treatment process using hydrochloric acid resulted reducing the particles size of fly ash from 1.2 µm to 0.95 µm. Zeta potential value increased to + 7.20 mv. Batch adsorption process showed that the removal efficiency decreased as the primary dye concentration increased. It increased when fly ash loading and contact time increased. Dyes removal was achieved up to 99.7% using TCFA loading 3gL−1 for initial dye concentration10 mgL−1. Studies on equilibrium revealed that the equilibrium data was closely fitted to the Freundlich and Langmuir isotherm models. Kinetic study of adsorption process was studied in detial. Based on high correlation coefficient (R2 = 0.999), the results were followed pseudo second-order model. [ABSTRACT FROM AUTHOR]

The use of waste materials in the construction and maintenance of roads is increasing at an alarming rate. Reclaimed asphalt pavement (RAP), a recyclable aggregate produced during the demolition of old flexible pavements and fly ash are examples of industrial wastes. This study examined the suitability of RAP in the production of asphalt concrete to replace natural aggregate partially, and modified with Fly ash. The optimum bitumen content (OBC) 6% was used for the asphalt mix designed. The properties of natural aggregates and RAP were determined. Fly ash was subjected to X -- Ray Fluorescence Energy Dispersive Analysis (X--RF) to know its chemical composition, and assessed for the suitability of all the component materials for their use in asphalt concrete. The best performance asphalt concrete with RAP was thereafter treated with 4% fly ash (class f), and Indirect Tensile Strength test was conducted on this sample to know the damage effect on asphalt concrete inform of fatigue cracks and rutting due to traffic load, and its performance resistance to moisture damage. The results of this study showed that asphalt concrete properties can be best improved with the use of 40% RAP content modified by 4% fly ash. [ABSTRACT FROM AUTHOR]

There are many industrial waste products used in the construction industry like rice husk ash, fly ash phosphogypsum, marble powder, cenosphere, silica fume, copper slag, granulated blast furnace slag, etc. It is observed that the use of all waste materials is beneficial for improving the properties of cement concrete and also making a hunk of lightweight cement concrete. In that material, the cenosphere is the most economical material in the construction industry, so both waste materials are used in most of the experimental works. This review focuses on the concrete prepared by replacing cement and fine aggregate with the cenosphere at various percentages for the preparation of lightweight cement concrete. The usual way to use cenosphere is up to 30% replacement as fine aggregate or 20% replacement of cement gives good results. These reviews discuss the usability and extraction of cenosphere from fly ash, its properties, and applications. Also observed are the final optimum percentages for compressive strength, split tensile strength, and flexural strength for 7, 14, and 28 days. [ABSTRACT FROM AUTHOR]

Geopolymer concrete has been developed as a means of reducing carbon dioxide (CO2) emissions due to concrete manufacturing, which account for around 5-10% of the total global CO2 emissions. Additionally, this innovative material aims to utilize industrial waste as a sustainable resource. This study concentrates on developing a geopolymer mortar composition comprising 70% fly ash and 30% metakaolin. The mixture also includes 14 molars of sodium hydroxide, sodium silicate, saturated surface dry sand, water at a volume of 10% of the mix, and 1.5% superplasticizer. The solution-to-solid materials ratio was established at 0.55 while the ratio between sodium silicate and sodium hydroxide was established at 2.5:1. The geopolymer mortar was enhanced by rice husk fibers at varying volume percentages of 1%, 1.5%, and 2%. Additionally, waste paper, in the form of paper ash, was introduced as filler at a volume percentage of 5%. Following the demolding process, the specimens were cured in the controlled environment of an oven, with the temperature set at 60 °C for a period of 24 hr. Subsequently, the cured samples were stored for 7 and 28 days and then were tested. When different amounts of rice husk fibers were mixed in with a fixed amount of 5% paper ash, the flexural resistance of the geopolymer mortar increased significantly. After 7 days of curing, it was seen that the flexural strength experienced an increase of 4%, 13%, and 25%, and a further increase of 11%, 18%, and 31% after 28 days of curing. The results of the impact test showed a notable enhancement in impact resistance and energy absorption when incorporating paper ash and rice husk fibers. Specifically, the initial crack results exhibited a 50% rise, while the specimen failure after 28 days of curing showed a 66% improvement. [ABSTRACT FROM AUTHOR]

Alkali-activated slag and fly ash (FA)-blended seawater sea sand concrete (AASC) is a new type of concrete produced without Portland cement or river sand. The advantages of utilising industrial waste and marine resources are that they are not only eco-friendly but cost-saving. This study aimed to investigate the properties of AASC exposed to elevated temperatures. Slag and FA were activated using NaOH and water glass solutions for mixing AASC. Heating and compressive tests were conducted to analyse the thermal and compressive properties of the AASC. The results showed that the AASC with higher FA content (Type II) had fewer flaky structures and more integral interfacial transition zones than the other type of AASC (Type I) after exposure to 600 °C. Type I AASC had better mechanical performance at temperatures below 400 °C but was inferior to Type II AASC beyond 600 °C. A compressive constitutive model was proposed for AASC. [ABSTRACT FROM AUTHOR]

Recent advances in the field of composite materials, aligning them with cost-effectiveness and environmental sustainability, have made the development of materials from industrial waste an attractive area of research. This work introduces an innovative approach for the reuse of globally available industrial waste by hybridizing organic and inorganic by-products to create low-cost composite materials with synergistically enhanced performances. Herein, industrial wastes, namely powdered wood chips (PWC) from the woodworking industry and fly ash (FA) derived from bagasse burning, were incorporated in a thermoplastic polypropylene (PP). Hybrid PP/PWC/FA composites at 70/20/10, 70/15/15 and 70/10/20 wt% were manufactured via extrusion process, followed by injection molding. Micrographic observations and infrared spectroscopy reveal that PWC particles have good physical adherence with PP. In contrast, the hydrophilic nature of FA leads to the creation of gaps at the interface due to the poor interfacial adhesion. The latter difference is reflected in the combined void nucleation modes of particle–fracture and particles–matrix interface decohesion during hybrid composites' tensile deformation. This provides a good synergistic stiffening effect for 70/20/10 wt% PP/PWC/FA hybrid composite, which offers the highest Young's modulus improvement of about 44.43%, while benefiting from balanced tensile strength and strain at yield. Furthermore, a two-way ANOVA at a significance level of 5% also proved the significant effect of PWC and FA reinforcement on the tensile parameters, as the p-values were below 0.05. Melt rheological properties demonstrate complex viscosity decrement for hybrid composites, suggesting a reduction in the energy required during production. Overall, the novel, high-performance hybrid composites developed can be manufactured with less energy consumption and are suitable for applications requiring high-temperature resistance and stiffness such as automotive, construction, and beyond. [ABSTRACT FROM AUTHOR]

In order to improve the high-value utilization of industrial solid waste materials, this study prepared a solid waste-based cementitious material (SWCM) using slag, fly ash, desulfurization gypsum, and gangue. The mechanical strength and hydration process of the SWCM and an ordinary Portland cement (OPC) were studied. The results showed that the compressive strength of the SWCM was lower than that of OPC at 3 d, but the compressive strength exceeded that of OPC after 7 d. The isothermal calorimetry results showed that the induction period of the SWCM was five times that of OPC, and the total 4 d exothermic amount of OPC was 1.7 times that of the SWCM. XRD and SEM showed that the hydration products of the SWCM were mainly ettringite (AFt) and hydrated calcium silicate gel (C-S-H). The unconfined compressive strength and dry shrinkage of stabilized macadam were also studied by using the SWCM to replace OPC. The results indicated that the unconfined compressive strength of the SWCM-stabilized macadam is comparable to that of the OPC-stabilized macadam. The dry shrinkage strain was only 79.7% of the OPC- stabilized macadam. [ABSTRACT FROM AUTHOR]

In light of the urgent need to develop environmentally friendly materials that, at some point, will allow the reduction of concrete and, consequently, cement consumption—while at the same time allowing the reuse of waste and industrial by-products—alkali-activated fly ash (AAFA) geopolymer composite emerges as a material of great interest. The aim of this study was to investigate the physico-mechanical performance of composites based on AAFA binders and the effect of different types of aggregates on these properties. The experimental results indicate variations in flexural and compressive strength, which are influenced both by the nature and particle size distribution of aggregates and the binder-to-aggregate ratio. The analysis of the samples highlighted changes in porosity, both in distribution and pore size, depending on the nature of the aggregates. This supports the evolution of physico-mechanical performance indicators. [ABSTRACT FROM AUTHOR]

Stabilization and solidification (S/S) using cement and lime is a common remediation method for oil-polluted soils. Secondary stabilizers and industrial wastes have recently attracted research attention due to their lower cost and greater environmental compatibility as a full/partial replacement of cement/lime. This study examined the effects and mechanism of action of secondary stabilizers and industrial wastes on the geotechnical feature of oil-polluted soils with a review of the literature. The main objective was to provide a suitable platform to use these inexpensive and environmentally friendly materials for the treatment of oil-polluted soils. The other objective was to determine the magnitude of changes in geotechnical parameters of oil-contaminated soil using S/S. This research examined the effect of secondary stabilizers and industrial wastes, including fly ash, slag, rice husk ash (RHA), cement kiln dust (CKD), limestone powder, and nanoparticles in the S/S process; investigated the micro- and macro-structure of the S/S of oil-polluted soils after incorporating these materials; and discussed the advantages and major challenges of these substances. The dosage of the said materials for improving the geotechnical features of oil-contaminated soils in acceptable values was also determined. Based on the findings, 20–60% fly ash, 10–15% slag, 5% RHA, 5–10% CKD, and 2.25% nanoclay improve the geotechnical characteristics of oil-polluted soils. CKD used alone for the S/S of oil-polluted soil yields superior performance due to having similar performance and a chemical formula close to that of cement. CKD increases compressive strength by at least 70% more compared to other by-products. [ABSTRACT FROM AUTHOR]