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Showing papers on "Fly ash published in 2021"


Journal ArticleDOI
TL;DR: In this article, the state-of-the-art treatment technologies and novel resource utilization approaches for the MSWI fly ash were reviewed and the latest understanding of immobilization mechanisms and the use of advanced characterization technologies were elaborated to foster future design of treatment technologies.

135 citations


Journal ArticleDOI
16 Feb 2021-Fractals
TL;DR: The utilization of phosphorus slag (PHS) to replace the fly ash in the construction of hydraulic projects has attracted a growing attention in China as mentioned in this paper, and the influence of PHS fineness an...
Abstract: The utilization of phosphorus slag (PHS) to replace the fly ash in the construction of hydraulic projects has attracted a growing attention in China. In this study, the influence of PHS fineness an...

130 citations


Journal ArticleDOI
TL;DR: The results showed that, compared to the AAFA, blending 10 % metakaolin in AAFA significantly improved both 28-day and 90-days compressive strengths, which was almost 200 % higher than that of AAFA.

112 citations


Journal ArticleDOI
TL;DR: In this article, the effect of mix proportioning on fresh, hardened and durability properties of fly ash and fly ash-slag geopolymer mortar is discussed. But, the main focus of this paper is on the quality of the mortar.

109 citations


Journal ArticleDOI
TL;DR: In this paper, the compressive strength of slag with D50 − 3.1μm activated by 4% Na2O-E of NS reached 36.2MPa and 77.3MPa at 28-d and 90-d age.

92 citations


Journal ArticleDOI
TL;DR: In this paper, the effect of high temperatures on lightweight geopolymer concrete and lightweight ordinary concrete made of natural pumice and lightweight expanded clay aggregate (LECA) with the addition of trapped air was examined.

88 citations


Journal ArticleDOI
TL;DR: In this paper, the authors provide a comprehensive review of the sulfate attack performance of fly ash, slag, silica fume, and metakaolin and assess the reduction in expansion of SCM and OPC blends with a range of replacement rates compared to an OPC control.

87 citations


Journal ArticleDOI
TL;DR: In this paper, the impact of temperature exposure (up to 1000°C) on the microstructure and the mechanical properties of the geopolymer mortars was evaluated. And the results showed that the mortar with no slag addition yielded better performances at high temperature.

85 citations


Journal ArticleDOI
TL;DR: In this article, the sources and characteristics of heavy metals and persistent organic pollutants in MSWI fly ash, and comprehensively compares and discusses various treatment methods, such as thermal treatment, pyrolysis process, hydrothermal treatment, solidification/stabilization (S/S) method and leaching process.

83 citations


Journal ArticleDOI
TL;DR: This review helps in better understanding of the behavior of FA-based concrete as a sustainable and eco-friendly material used in construction and building industries.
Abstract: Development of sustainable concrete as an alternative to conventional concrete helps in reducing carbon dioxide footprint associated with the use of cement and disposal of waste materials in landfill. One way to achieve that is the use of fly ash (FA) as an alternative to ordinary Portland cement (OPC) because FA is a pozzolanic material and has a high amount of alumina and silica content. Because of its excellent mechanical properties, several studies have been conducted to investigate the use of alkali-activated FA-based concrete as an alternative to conventional concrete. FA, as an industrial by-product, occupies land, thereby causing environmental pollution and health problems. FA-based concrete has numerous advantages, such as it has early strength gaining, it uses low natural resources, and it can be configurated into different structural elements. This study initially presents a review of the classifications, sources, chemical composition, curing regimes and clean production of FA. Then, physical, fresh, and mechanical properties of FA-based concretes are studied. This review helps in better understanding of the behavior of FA-based concrete as a sustainable and eco-friendly material used in construction and building industries.

83 citations


Journal ArticleDOI
TL;DR: It is demonstrated that phosphate-modified CAC is a promising binder for S/S of hazardous MIFA, and fulfilled the compressive strength and leachability requirements for on-site reuse.

Journal ArticleDOI
TL;DR: In this paper, a review of the use of fly ash and slag as mine paste backfill material has been provided, where the effect of alternative binders, such as fly ash, superplasticizer, admixture, and fibre reinforcement are comprehensively reviewed.

Journal ArticleDOI
TL;DR: The mechanism of geopolymerization is summarized, including the controlling parameters and different raw materials (fly ash, kaolinite and metakaolin, slag, red mud, silica waste, heavy metals waste, and others) with particular focus on recent studies and challenges in this area.

Journal ArticleDOI
TL;DR: In this paper, the influence of different FA fineness, UFA content (30-70%), and curing regimes on the compressive strength and microstructure of steam-cured high volume fly ash cement composites were studied.

Journal ArticleDOI
TL;DR: In this article, the effect of sodium silicate (SS) as an accelerator on early age mechanical and microstructure properties of coal fly ash backfill was analyzed for a dosage of 0.5, 1 and 1.5 wt% in CCB.

Journal ArticleDOI
TL;DR: In this article, the compressive strength of masonry units (red clay brick, roof tile, hollow brick) and glass-based precursors was evaluated using CDW-based materials.

Journal ArticleDOI
TL;DR: In this article, a comprehensive review of the research progress on activated kaolinitic clay as SCM in the last decade is presented, which systematically introduces the essential properties, activation mechanism and pozzolanic reactivity assessment of calcined clay.
Abstract: The development of a green alternative that can partially or completely substitute the Ordinary Portland cement (OPC) as a practical construction material with low CO2 footprint is an important subject to researchers for decades. The use of artificial pozzolanic materials, e.g. fly ash, slag, silica fume, etc. cannot meet the huge-scale demand for cement replacement. Kaolinitic clay, with its high pozzolanic reactivity after activation and abundant resources worldwide, is regarded as a promising supplementary cementitious material (SCM) for cement. Recent studies have addressed that the utilization of calcined kaolinitic clay as SCM can effectively improve the properties of cement products. This paper presents a comprehensive review of the research progress on activated kaolinitic clay as SCM in the last decade. It systematically introduces the essential properties, activation mechanism and pozzolanic reactivity assessment of kaolinitic clay. Application of calcined clay in two different cementitious systems (calcined clay blended cement and limestone calcined clay cement) is reviewed from the aspects of workability, mechanical properties, and long-term durability properties with the mechanism discussion. Finally, the environmental and economic impacts of the application of calcined clay in different cementitious systems are discussed.

Journal ArticleDOI
TL;DR: In this article, a cement-free geopolymer concrete (GPC) mix is prepared using locally produced fly ash with varying NaOH concentrations (8−M−16M), Na2SiO3/NaOH ratios (1.5−2.5) and alkaline activator to fly ash (AA/FA) ratios (0.4−0.6) to investigate the influence of AL on the mechanical properties of GPC cured at ambient temperatures.

Journal ArticleDOI
TL;DR: When Mn-Ce is 1:1, the denitration efficiency is higher, the total conversion rate of NO is the highest and the deactivation time is the longest, the catalyst is resistant to sulfur performance is also the best.

Journal ArticleDOI
TL;DR: In this paper, the feasibility of blending more than 50% of calcined clay (LC2) in cement was explored in order to achieve greener blended cement, and five LC2 replacement levels were studied, including 25, 50, 60, 70% and 80% by weight of cement.

Journal ArticleDOI
TL;DR: In this paper, the micro carbon fiber (CF) was used to enhance the mechanical properties of fly ash geopolymer containing fine recycled concrete aggregate (RCA), where natural river sand was replaced with RCA at 0, 50, and 100% by volume.
Abstract: In this study, the micro carbon fiber (CF) was used to enhance the mechanical properties of fly ash geopolymer containing fine recycled concrete aggregate (RCA). Natural river sand was replaced with RCA at 0, 50, and 100% by volume. The CF was used as additive material by incorporating into the mixture at 0, 0.1, 0.2, and 0.3% by weight of fly ash. The results showed that the CF enhanced the mechanical properties of geopolymer containing RCA through the increased nucleation sites for geopolymerization reaction and the bridging effect of the fiber. For the mix with 100% RCA, the incorporation of 0.2% CF resulted geopolymer mortar with higher compressive and splitting tensile strengths . For the flexural strength and surface abrasion resistance , best results were obtained with the use of 50%RCA with significant improvement in both flexural strength and surface abrasion resistance. The incorporation of CF thus increases the use of recycled fine aggregate without resort to natural fine aggregate .


Journal ArticleDOI
TL;DR: In this paper, fly ash particles were employed as the support and membrane layer of composite ceramic membranes to match the sintering temperature of the kaolin material and fly ash support, rigid alumina particles were introduced into the supports (AFA supports).

Journal ArticleDOI
TL;DR: In this paper, an experimental study aimed to characterize S transformations in TDS as a function of temperature (600-1000°C) and blend ratios of spent mushroom substrate (SMS) and calcium oxide (CaO) through thermodynamic equilibrium simulations.

Journal ArticleDOI
TL;DR: In this article, the authors present results of tests of modified concretes both with the addition of coal fly ash (CFA) ash and with an innovative nanoadmixture (NA) used to accelerate the strength growth in cement composites.

Journal ArticleDOI
TL;DR: In this paper, a review for the first time incorporates both municipal solid waste bottom ash and fly ash (MSW-FA) and discusses their physicochemical characterizations, leaching mechanisms, and pre-treatment methods.
Abstract: Waste destruction through incineration has widely become an acceptable and popular choice globally. Despite being regarded as a sustainable option, if not operated and managed properly, it can be one of the least environmentally preferred options. It is agreed that the waste from municipal solid waste (MSW) can be considered a renewable energy resource due to its potential of being converted from “waste” into useful products and energy. This review for the first time incorporates both municipal solid waste bottom ash (MSW-BA) and municipal solid waste fly ash (MSW-FA); and discusses their physicochemical characterizations, leaching mechanisms, and pre-treatment methods. Additionally, it incorporates, discusses, and critically reviews the recent advances and applications of MSW-BA and MSW-FA, and explore the potential of utilizing ashes as a sustainable option by conserving natural resources.

Journal ArticleDOI
TL;DR: In this article, a sequential chemical roasting, water leaching, and acid leaching process was developed for the recovery of rare earth elements (REEs) from coal fly ash (CFA).

Journal ArticleDOI
TL;DR: In this article, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR), while adding silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented.
Abstract: The existing form of self-compacting concrete (SCC) comprises of a large amount of powdered and fine materials. In this study, a part of the cementitious material was replaced with constant high-volume fly ash, and a portion of fine aggregates was substituted by crumb rubber (CR). Besides that, silica fume (SF) was added, with the hope that by implementing a new type of nanomaterial, the loss in mechanical strength due to previous modifications such as rubberization and replacement will be prevented. Two variables were found to influence the constituent/component in the mix design: SF and CR. The proportion of SF varies from 0% to 10%, while that of CR from 0% to 30% by volume of the total river sand, where 55% of cement was replaced by the fly ash. A total of 13 rubberized SCC samples with CR and SF as controlling variables were made, and their design mix was produced by a Design of Experiment (DOE) under the Response Surface Methodology (RSM). The results reveal a slight increase in the mechanical properties with the addition of SF. The theoretical mathematical models and equation for each different mechanical strength were also developed after incorporating the experimental results into the software.

Journal ArticleDOI
TL;DR: In this article, the authors used fly ash and desulfurized gypsum (DG) as the main raw materials to prepare road base materials based on the different (CaO+Na2O)/(SiO2+Al2O3) molar ratio, and its mechanical properties, durability, microstructure and environmental performance were investigated.

Journal ArticleDOI
TL;DR: In this paper, form-stable fly ash/lauric acid-myristic acid eutectic mixture composites (FSC) were incorporated into the standard cement mortar to produce novel cement mortars with ability of heat charging/discharging properties.