Ash Waste Research Articles

Mechanical Properties of Recycled Aggregate Concrete with Industrial Waste Ash

This study investigates the performance of concrete incorporating various recycled fine aggregates, including recycled brick aggregates, Fly Ash (FA), and Sugar Cane Bagasse Ash (SCBA). The test results showed that the mechanical properties were adversely affected when utilizing recycled brick or concrete aggregates, whereas FA or SCBA enhanced them. The water absorption potential of recycled bricks was proportional to the reduction in mechanical properties. FA and SCBA enhanced compressive strength and increased flexural strength up to 175.72% and 225.51%, respectively, at 20% replacement. The inclusion of recycled brick and concrete aggregates raised water absorption, while FA and SCBA significantly lowered it, improving the overall performance.

Effect on Mechanical Property of Polypropylene Mixed with Charcoal Waste Ash through Melt Compounding

This study explores the use of charcoal waste ash, a by-product of human activities, as a filler in polypropylene matrices. The samples were mixed using the melt compounding method using an internal mixer at 1wt%, 2wt%, 5wt%, 7wt% and 10wt%. Tensile strength peaked at 29.85MPa at 2wt% while the flexural strength peaked well above pure PP at 45.5MPa at 7wt%. Charcoal waste ash is possible to enhance the mechanical properties of polypropylene, suggesting its potential as a sustainable material in polymer composites.

Combine the use of rice husk ash and quarry waste for sustainable masonry blocks: mechanical characteristics, durability and eco-benefits

The construction industry faces a growing demand for eco-friendly practices. This study explores the viability of incorporating quarry waste and rice husk ash (RHA) as partial replacements for cement and river sand in masonry block production. The research investigates the combined effect of these waste materials on the critical characteristics of cement blocks, including physical properties, mechanical behaviour, and resistance to environmental degradation. A cost-benefit analysis also considers economic, environmental, and societal factors. Replacing river sand with quarry waste in the mortar mix resulted in higher density and improved impact resistance. Also, it exhibited lower water absorption and early-age strength than the river sand. Partial cement replacement with RHA yielded positive results at lower incorporation levels. Up to 20% RHA content enhanced compressive and flexural strength while reducing embodied energy and CO₂ emissions. However, higher RHA replacements negatively affected these properties. The optimal balance between cost-effectiveness, environmental benefits, and structural performance was achieved with a combination of 20% RHA and complete quarry waste replacement. This approach offers a sustainable and potentially cost-saving alternative for conventional masonry block production. This research demonstrates the potential of utilizing waste materials in construction while promoting eco-friendly practices and responsible waste management in the industry.

Enhanced mechanical properties and mechanism of iron ore tailings-based geopolymers modified by municipal solid waste incineration fly ash

Iron ore tailings, coal fly ash and municipal solid waste incineration fly ash (MSWI FA), as solid waste, must be disposed of. Iron ore tailings, coal fly ash and MSWI FA were successfully prepared into high-performance geopolymer. The compressive strength of optimal geopolymer reached 57.89 MPa. Based on XRD, FTIR, SEM and chemical extraction analysis, C-(A)-S-H was the main gel product along with N-A-S-H. It was found that the dominant hydration process of geopolymer was changed from diffusion process (D) to phase boundary reaction process (I) after MSWI FA addition based on hydration reaction rate curves and dynamic simulation, releasing more hydration heat and generating more C(N)-A-S-H gels. Heavy metal content in the optimal geopolymer was below the limits of Class I screening value of development land (GB 36600-2018). Ef and Cf of the optimal geopolymer were 30.9 MJ/ton/MPa and 6.88 kg CO2/ton/MPa, affirming the viability of utilizing iron ore tailings, coal fly ash and MSWI FA as raw materials for geopolymer production, which provides a promising collaborative resource method of processing them.

Research on Extracting Silicon and Iron Oxide from the Waste Ash of Mongolian Fourth Thermal Power Plant

In this research, we extracted silicon and iron oxides from the waste ash of the Mongolian fourth thermal power plant by a precipitation method. The samples were analyzed using XRD, XRF, BET, and SEM, and the following conclusions were reached. From the quantitative analysis of the chemical composition, the bottom and fly ash of the Mongolian fourth thermal power plant belong to the acid ash. The results of instrumental analysis of iron oxide obtained from the waste ash (XRF, XRD, BET, SEM), the ratio of ash to hydrochloric acid is 1:6, the hydrochloric acid concentration is 20%, the reaction temperature is 75°C, stirring speed is 250 rpm. The properties of the prepared iron oxide are the best and yield 20%, purity of 41.587%, average pore diameter of 7.5379 nm, and specific surface area of 38.87 m2 /g.The results of instrumental analysis of silicon dioxide obtained from the waste ash (XRF, XRD, BET, SEM) show the ratio of ash to hydrochloric acid is 1:6, the hydrochloric acid concentration is 20%, the reaction temperature is 75°C, stirring speed is 200 rpm. The yield is about 75%, the purity is 99.999%, the average pore diameter is 27.96 nm, and the specific surface area is 353.59 m2 /g.

Scientific advances regarding the effect of carbonated alkaline waste materials on pozzolanic reactivity

Using alkaline waste materials as biomass ash (BA), Recycled Concrete Fines (RCF) from constructions and demolition waste (CDW) and ladle furnace slags (LFS), as CO2 massive sinks worldwide through the generation of new potential SCM by Accelerated Carbonation Technologies to reduce the cement industry's carbon footprint is increasingly attracting attention for its environmental benefits and the materials' improved performance in blended cement matrices. This paper employs characterization and identification techniques (XRF, XRD–Rietveld, SEM/EDX, BET, TG/DTG, FTIR, NMR) to analyse the effect of accelerated carbonation of white ladle furnace slag, siliceous construction and demolition waste and biomass ash on those materials' physical and mineralogical properties, their chemical reactivity and their pozzolan/lime systems' mineralogical phases. The results show that although behaviour differs depending on the carbonated waste materials' alkalinity, all three present notable increases in BET surface area (7–17.5 m2/g) and substantially altered potentially carbonatable mineralogical phases (e.g. portlandite, Ca-olivine, periclase, hydrated cement phases), which mostly transition towards calcite, due to the CO2 uptake. Thermodynamic modelling of the pozzolanic reaction indicates that CSH/C(A)SH) gels are the most stable phases, followed by ettringite, C4AH13 and C4AcH12.

Development of composition of fine-grained concrete based on ash-and-slag wastes for additive technology of manufacturing small architectural forms

Developing a fine-grained concrete composition for additive technologies is an important scientific and practical task, since traditional building mixtures are unsuitable for 3D printers, and special solutions are practically absent in mass production. This study aims to develop a composition of fine-grained concrete for additive technologies using local resources and ash and slag waste of the Ust-Kamenogorsk thermal power plant, which contributes to the expansion of the raw material base used in this area. The work was carried out taking into account the analysis of the literature review, which made it possible to identify key aspects and directions in the development of concrete mixtures for additive technologies. This article discusses the possibility of using ash and slag waste in concrete as a filler. Ash has a grain size comparable to river sand, so it can be used as a new material to replace fine filler. To obtain the mixture, 5 experimental mixtures and one reference sample were prepared. The optimal composition is considered to include 30% of M500 Portland cement, 40% of sand, and 30% of ash and slag. The physical and mechanical characteristics of this composition are as follows: the mobility of the mixture is 5.81 cm, and the setting completion time is 4 hours 19 minutes. The results of the sample tests confirmed that the created fine-grained concrete compositions are suitable for extrusion on construction 3D printers. The possibility of creating a composition based on local ash and slag waste for additive technologies used in producing small architectural forms was experimentally confirmed.

Evaluating the availability and carbon footprint of agricultural waste ashes: a strategy for achieving sustainable cement production in India

Evaluating the availability and carbon footprint of agricultural waste ashes: a strategy for achieving sustainable cement production in India

Effect of agricultural wastes as sugar beet ash, sugarcane leaf ash, and sugarcane bagasse ash on UHPC properties

This research investigates the use of novel agricultural waste ash, such as sugar beet ash (SBA), as partial cement substitutes to produce high-performance and sustainable concrete. In addition to SBA, sugarcane leaf ash and sugarcane residue ash were used as partial cement substitutes at 10 %–50 % by weight. To evaluate the efficiency of the ash used, strength index tests were conducted at 7 and 28 days of age. To evaluate the performance of UHPC incorporating agricultural waste ash, 22 mixtures were implemented. Tests of workability, mechanical, and transport properties, as well as microstructure analysis of UHPC, were performed. In addition, the effect of high temperatures up to 800 °C on compressive strength (CS) was investigated. The experimental results indicated that incorporating agricultural waste as cement substitutes, including SBA, improved the mechanical properties, enhanced its workability, and reduced chloride penetration of UHPC. The mixture containing 10 % SBA showed a CS of 170.8 MPa compared to the reference mixture of 167.2 MPa at 28 days of age. Microstructure analysis revealed that incorporating agricultural waste reduced the pore size and created a denser UHPC structure, which contributed to the improvement of UHPC properties. The results demonstrate the technical feasibility of using SBA as cement substitutes alone or in combination with SLA or SCBA for UHPC production and its potential for wider applications in the construction industry.

Evaluation of steel fibrous concrete impact resistance properties utilizing incinerated biomedical waste ash for a sustainable future construction

Evaluation of steel fibrous concrete impact resistance properties utilizing incinerated biomedical waste ash for a sustainable future construction

Rheology, shrinkage, mechanical properties and microstructure of ultra-light-weight concrete with fly ash cenospheres

Cenospheres are low-density and hollow microspheres derived from coal-fired power plant fly ash waste. This study aims to prepare ultra-light-weight (<1000 kg/m3 wet density) concrete using fly ash cenospheres (FAC). To begin with, FAC's shell thickness and the water absorption and desorption were characterized. A mixing procedure was designed to avoid the segregation between the FAC and cement slurry. FAC can affect the rheological properties of fresh mixture over time through absorption and desorption of free water. The presented ultra-light-weight concrete has several advantages compared to the ones prepared using foaming methods. First, shrinkage is significantly reduced due to FAC's internal restraint and curing effects. Secondly, it has good mechanical performance, especially in bending and is more environmentally friendly due to use of less cement. X-ray computed tomography illustrates that FAC ultra-light-weight concrete has smaller pores of more uniform size compared with those prepared using foaming methods. X-Ray diffraction, thermal gravimetry-derivative thermal gravimetry, fourier-transform infrared spectroscopy and scanning electron microscopy are employed for the hydration products and microstructure characterization. Outcomes prove that FAC can combine well with the cement matrix, and react with calcium hydroxide to produce C-A-S-H through pozzolanic reaction.

CO2-assisted gasification of Patagonian rosehip bio-wastes: Kinetic modeling, analysis of ash catalytic effects, and product gas speciation

In the present study, the valorization of two rosehip wastes –husk and seed– was performed, through the CO2 gasification of biochar obtained by pyrolysis. The kinetics of gasification in a CO2 atmosphere at different partial pressures was investigated, obtaining the activation energy (E), pre-exponential factor (A), conversion function (f(α)), and reaction order with respect to the partial pressure of CO2 (x). The rosehip seed waste biochar (RSWB) yielded the following parameters: E = 302.11 kJ/mol, A = 2.18×1012 1/(s atm0.64), f(α) = 321−α−1/3−1−1; while the rosehip husk waste biochar (RHWB) results were: E = 198.60 kJ/mol, A = 2.13 × 1008 1/(s atm0.64), f(α) = 21−α1/2. The reaction order was the same in both wastes and equal to 0.64. The greater reactivity of RHWB can be attributed to the catalytic effects of the ashes contained in the biomass. To evaluate this effect, tests were conducted on rosehip husk waste ash mixtures with orthoasphaltite mineral char in proportions of 1, 5, 7, and 10 % (m/m). Thermogravimetry determined that the gasification temperature decreased up to 200 °C compared to pure char. Additionally, dry gasification of raw biomass experiments were carried out, and the evolution of gaseous products was analyzed with FTIR spectroscopy, evaluating the absorbance profiles of CO, CH4, and CH3OH, and comparing them with those obtained in a pure N2 atmosphere. The results obtained demonstrated the potential of rosehip wastes as a source in thermochemical processes for its complete valorization in a production chain with a focus on biorefinery.

Enhancing sustainability in concrete construction: Utilizing copper slag for improved properties of geopolymer concrete

Geopolymer concrete (GPC), utilizing aluminosilicate precursor materials as binders, stands as an eco-friendly alternative to Portland cement concrete. These precursors commonly include natural resources like metakaolin, volcanic ash, and industrial solid waste such as fly ash (FA) and ground granulated blast furnace slag (GGBFS). However, despite not utilizing cement, GPC still faces environmental challenges due to the use of natural aggregates, leading to resource depletion. To mitigate this issue, researchers have explored replacing natural aggregates with waste materials, aiding both resource conservation and waste management. Copper slag (CS) is one such waste material with potential as fine aggregate in GPC. This study conducts a comprehensive evaluation of FA-GGBFS-based GPC incorporating CS as fine aggregate, revealing notable enhancements in transport, durability, and strength properties. The optimal replacement of 60 % natural sand with CS in GPC resulted in a 20–25 % increase in compressive strength, a 10–15 % improvement in slake durability, an 18–40 % reduction in water absorption, a 30–39 % decrease in permeable voids, and a 26–47 % reduction in depth of wear, all in comparison to the control specimen made with natural sand only. Thus, incorporating CS as a fine aggregate in GPC is recommended as an effective approach to enhance mechanical performance and durability, while contributing to sustainable construction practices.

Facile synthesis of layered spinel ferrite from fly ash waste as a stable and active ketonisation catalyst

Facile synthesis of layered spinel ferrite from fly ash waste as a stable and active ketonisation catalyst

Effect of Olive Waste Ash as a Partial Replacement of Cement on the Volume Stability of Cement Paste

Over the last decades, concrete has been excessively prone to cracks resulting from shrinkage. These dimensional changes can be affected by the incorporation of supplementary cementitious materials. This work used olive waste ash (OWA), which could substantially tackle this problem and achieve sustainability goals. For this issue, five cement paste mixes were prepared by replacing cement with OWA at different percentages varying from 0 to 20% by weight with a constant increment of 5%. The water-to-cement ratio was 0.45 for all mixes. Compressive strength and flexural strength were investigated at 7, 28, and 90 days. In addition, three shrinkage tests (drying, autogenous, and chemical) and expansion tests were also conducted for each mix and measured during 90 days of curing. The experimental findings indicated that there was a loss in compressive and flexural strength in the existence of OWA. Among all mixes containing OWA, the samples incorporating 10% OWA exhibited maximum strength values. Furthermore, the chemical and autogenous shrinkage decreased with the incorporation of OWA. However, the drying shrinkage decreased at lower levels of substitutions and increased at higher replacement levels. In addition, there was a growth in expansion rates for up to 10% of OWA content, followed by a decrease at higher levels (beyond 10%). Additionally, correlations between these volumetric stability tests were performed. It was shown that a positive linear correlation existed between chemical shrinkage and autogenous and drying shrinkage; however, there was a negative relationship between chemical shrinkage and expansion.

Fly-ash derived crystalline Si (cSi) Improves the capacity and energy density of LiNi0.8Co0.1Mn0.1O2 battery: Synthesis and performance

For decades, graphite has been the key ingredient in the anode of Li-ion batteries (LIBs). The search for high-capacity anode materials for Li-ion batteries (LIBs) has led to increasing interest in silicon (Si) as a potential replacement for graphite. This study presents an innovative approach to synthesizing crystalline Si (cSi) from type C fly ash, addressing both the need for improved LIB anodes and the challenge of industrial waste management. Our novel process involves a stepwise method of extraction, gelation using various mineral acids (HCl, H2SO4, and HNO3), magnesiothermic reduction, and purification. X-ray diffraction and energy-dispersive X-ray spectroscopy confirmed the production of high-purity SiO2 and cSi. Notably, a cSi-doped graphite anode (5 % Si) paired with LiNi0.8Mn0.1Co0.1O2 (NMC811) in a cylindrical cell achieved a minimum specific discharge capacity of 388 mAh/ganode after formation, surpassing the theoretical capacity of graphite (372 mAh/g). This demonstrates that even a small amount of cSi can significantly enhance anode performance. Our scalable, simple, and economical process offers a dual benefit: improving battery characteristics while providing an efficient method for fly ash waste utilization. This approach paves the way for sustainable production of high-performance LIB anodes while addressing critical waste management challenges.

Remanufacturing construction and demolition waste and incineration ashes into eco-blocks: Quantitative sustainability assessment

This study performed a sustainability evaluation of a proposed business for remanufacturing concrete materials from construction and demolition waste (CDW) and ash from the combustion of municipal solid waste (MSW) to produce eco-blocks for construction applications. Six possible industrial remanufacturing alternatives are proposed based on commercially available industrial machinery and their economic sustainability was compared by a cost and profit feasibility study. Furthermore, the technical feasibility was evaluated by considering the maturity of the selected machinery based on the relationships among the cost–productivity, power–productivity, and number of workers–productivity pairs. The proposed remanufacturing business achieves a maximum profit of 17,643 USD/day with a minimum remanufacturing cost of 30.65 USD/t for the production of 529 t of eco-blocks in an 8-h factory shift. A quantitative environmental sustainability assessment was performed using the remanufacturing cost, profit, concrete savings, energy savings, CO2 emission savings, and eco-cost savings as criteria based on demographic statistics from the literature for current and predicted CDW and MSW generation. CDW and incineration ash are widely available, so the proposed process is viable worldwide. Based on the technical, economic, and environmental sustainability results, a final sustainability index of 0.874 was calculated, which exceeds literature thresholds for a sustainable business, indicating that the proposed eco-block remanufacturing process has the potential to generate substantial profits, while positively contributing to reducing waste and energy usage by recovering valuable resources and producing value-added products. The remanufactured eco-blocks are prepared in the same way as typical concrete blocks and can be used for all of the same residential, commercial, and industrial construction and landscaping applications. The remanufactured eco-blocks have several advantages over typical concrete blocks, including a much lower manufacturing cost (∼50 % lower), significant environmental and resource savings by avoiding the use of new sand and gravel resources, and improved mechanical properties.

Advancements in Lightweight Artificial Aggregates: Typologies, Compositions, Applications, and Prospects for the Future

Currently, the environment and its natural resources face many issues related to the depletion of natural resources, in addition to the increase in environmental pollution resulting from uncontrolled waste disposal. Therefore, it is crucial to identify practical and effective ways to utilize these wastes, such as transforming them into environmentally friendly concrete. Artificial lightweight aggregates (ALWAs) are gaining interest because of their shift in focus from natural aggregates. Researchers have developed numerous ALWAs to eliminate the need for natural aggregates. This article explores the diverse applications of ALWAs across different industries. ALWAs are currently in the research phase due to various limitations compared to the availability of the various natural aggregates that form more durable solutions. However, researchers have discovered that certain artificial aggregates prioritize weight over strength, allowing for the effective use of ALWAs in applications like pavements. We thoroughly studied the various ALWAs discussed in this article and found that fly ash and construction waste are the most diverse sources of primary material for ALWAs. However, the production of these aggregates also presents challenges in terms of processing and optimization. This article’s case study reveals that ALWAs, consisting of 80% fly ash, 5% blast-furnace slag, and only 15% cement, can yield a sustainable solution. In the single- and double-step palletization, the aggregate proved to be less environmentally harmful. Additionally, the production of ALWAs has a reduced carbon footprint due to the recycling of various waste materials, including aggregates derived from fly ash, marble sludge, and ground granulated blast-furnace slag. Despite their limited mechanical strength, the aggregates exhibit superior performance, making them suitable for use in high-rise buildings and landscapes. Researchers have found that composition plays a key role in determining the application-based properties of aggregates. This article also discusses environmental and sustainability considerations, as well as future trends in the LWA field. Simultaneously, recycling ALWAs can reduce waste and promote sustainable construction. However, this article discusses and researches the challenges associated with the production and processing of ALWAs.

Modelling the properties of aerated concrete on the basis of raw materials and ash-and-slag wastes using machine learning paradigm

The thermal power industry, as a major consumer of hard coal, significantly contributes to harmful emissions, affecting both air quality and soil health during the operation and transportation of ash and slag waste. This study presents the modeling of aerated concrete using local raw materials and ash-and-slag waste in seismic areas through machine learning techniques. A comprehensive literature review and comparative analysis of normative documentation underscore the relevance and feasibility of employing non-autoclaved aerated concrete blocks in such regions. Machine learning methods are particularly effective for disjointed datasets, with neural networks demonstrating superior performance in modeling complex relationships for predicting concrete strength and density. The results reveal that neural networks, especially those with Bayesian Regularisation, consistently outperformed decision trees, achieving higher regression values (Rstrength = 0.9587 and Rdensity = 0.91997) and lower error metrics (MSE, RMSE, RIE, MAE). This indicates their advanced capability to capture intricate non-linear patterns. The study concludes that artificial neural networks are a robust tool for predicting concrete properties, crucial for producing non-autoclaved curing wall blocks suitable for earthquake-resistant construction. Future research should focus on optimizing the balance between density and strength of blocks by enhancing the properties of aerated concrete and utilizing reliable models.

Analysis Of Flexural Resistance And Environmental Feasibility Of Ferrocement Concrete Slabs From Fly Ash And Sandblasting Waste

Sandblasting waste from the shipbuilding industry and fly ash waste from industry and electric steam power plants in Indonesia are relatively high in quantity, are B3, and can potentially cause serious environmental pollution. This research aims to utilize this waste as material for ferrocement concrete, where the SiO2 and Al2O3 content from fly ash replaces some of the cement, silica sand from sandblasting waste replaces sand, and additional wire mesh as reinforcement. The method used is a quantitative experiment, where the material to be used is tested for gradation and TCLP. The finished ferrocement concrete is tested for flexural strength. The test results show that the raw material meets the gradation standards in SNI 03 2834 2000, as well the TCLP test results which show that the B3 heavy metal content is Barium, Zinc, and Copper in the sandblasting waste value is below the quality standards of PP No. 22 of 2021 Appendix XI so that all materials can be used for mix designs. The mix design created has a composition ratio of 1S:1.5PB, 1S:1.5PB:50AT, 1S:2PB, and 1S:1PB:50AT. The 1S:2PB ratio composition has the highest average flexural strength, namely 17.46 MPa, which is suitable for light vertical load construction work