Composition Of Fly Ash Research Articles

From Waste to Strength: A Comprehensive Review on Using Fly Ash in Composites with Enhanced Mechanical Properties

This article explores the diverse applications of fly ash (FA), a by-product generated during the combustion of coal. The introductory segment thoroughly comprehends the origins, composition, and widespread occurrence of FA. FA, which comprises an estimated 38% of worldwide power generation, frequently encounters disposal and storage obstacles on account of its classification as non-hazardous waste in the majority of countries. The environmental issues linked to the dispersal of FA are underscored in the problem statement, which further emphasizes the urgency for sustainable alternatives. Due to the fugitive emissions and potential health hazards associated with metal melting in FA, it is critical to investigate novel applications and disposal techniques immediately. Environmental sustainability is a primary focus of research, with the development of synthetic FA composites being one such alternative. The analysis presents significant findings that underscore the wide-ranging applications of FA. These applications include its utilization as a filler in composites, as well as its incorporation into cement and geo-polymerization processes. Notably, (10-20) wt. % Nano-FA enhances epoxy-based composites, showcasing remarkable improvements in tensile strength, flexural strength, and impact resistance. In thermoplastic composites, substantial enhancements occur within the (5–10) wt. % FA range, but exceeding optimal ranges weakens matrix-fiber interaction, leading to diminishing returns. The article emphasizes the criticality of FA in improving the mechanical and thermodynamic characteristics of substances, specifically within the domain of composites. The investigation into FA nanoparticles, including their processing techniques and surface treatments, unveils encouraging prospects for enhancing material characteristics.

Immobilization mechanism of heavy metals by crystals and liquid phase during melting treatment of MSWI fly ash

Melting treatment has emerged as a promising technology for managing municipal solid waste incineration (MSWI) fly ash owing to its advantageous features of effective detoxification and volume reduction. The melting treatment of MSWI fly ash involves the immobilization of heavy metals by crystals and liquid phase. Herein, the immobilization mechanism of heavy metals (Cu, Pb and Cd) by the crystals and the liquid phase was investigated using melting experiments, thermodynamic calculations and density functional theory (DFT) calculations. Results demonstrate that the immobilization of heavy metals is influenced by a combination of factors: the reaction of heavy metals, physical encapsulation ability of the liquid phase and chemical fixation ability of both the crystals and the liquid phase. An increase in the content of SiO2 and Al2O3 promotes the conversion of heavy metals oxides into heavy metals chlorides. Furthermore, an increase in the content and polymerization degree of the liquid phase facilitates the physical encapsulation of heavy metals chlorides. The chemical fixation ability of the crystals and the liquid phase differs for Cu and Pb, while Cd cannot be immobilized through chemical fixation. To enhance the immobilization of heavy metals during melting treatment, the chemical composition of MSWI fly ash should be adjusted within the anorthite region of the ternary phase diagram. This study provides valuable insights into the immobilization mechanism of heavy metals by the crystals and the liquid phase during the melting treatment of MSWI fly ash.

A STATE OF ART AND PROSPECTS OF FLY ASH MANAGEMENT

The basic data on the volume of formation and composition of fly ash, which is a product of coal combustion at thermal power stations, are given. The analysis of the current state of ways of managing fly ash makes it possible to distinguish the following main directions: physical-mechanical, physical-chemical, biological and combined methods of handling it, which are used in agriculture (use as fertilizers and pesticides; chemical land reclamation: regulation of the structure and pH of the soil); during earthworks (reinforcement of weak and expansive soils, use as tamponage compositions, arrangement of embankments and dams); road construction (strengthening of the soil for the lower layers of the road surface; production of asphalt, cement-concrete mixtures for arranging the foundations of road clothing, as well as crushed stone-sand and gravel-sand mixtures reinforced with cement); building materials industry (cement, concrete, building solutions, geopolymers, bricks, building blocks, glass, glass ceramics, building ceramics, porous ceramics, rolled waterproofing materials); in protective coatings (paints, enamels, enamel glass, shotcrete, heat-protective and heat-insulating coatings); as sorbents and catalysts and their carriers; in mechanical engineering (abrasive, frictional, filtering and lubricating materials, materials for soldering, foundry sand forms or rods); as other materials (pigments, polymer composites, elements of chemical sources of electric current, accumulators of certain substances, carbon nanoparticles (fullerenes, nanotubes), cosmetics and hygiene products); in pyrometallurgical and hydrometallurgical methods of recovery of chemical elements; in alloys and metal matrix composites; for extracting rare earth elements. Currently, the most appropriate methods of disposal of fly ash are either its direct use with a minimal change in its properties, or its use with minimal processing and minimization of the formation of new waste, in particular in the building materials industry and road construction. Bibl. 164, Fig. 3.

Combined effects of carbonation and salt solution on chloride desorption, pH, and composition of fly ash blended pastes

The most consumed human-made material, concrete, is permeable and chloride-bearing deicers penetrate the concrete, causing deterioration. Chloride ions exist in concrete in two forms: free and bound chlorides. Free chlorides are the primary cause of chloride-induced corrosion because they can move in concrete pores, reaching the rebar surface to initiate corrosion. Bound chlorides are those chloride ions that are adsorbed by the concrete matrix and cannot actively participate in reinforcement corrosion. Although chloride binding is a beneficial process, chloride binding is reversible. In addition, most concrete infrastructures are subject to environmental attacks such as carbonation, causing pH reduction in the concrete pore solution and subsequently resulting in the release of bound chlorides (chloride desorption). The combined effects of carbonation and chloride attack on fly ash containing pastes are not well-studied, particularly concerning their impact on chloride desorption, pH changes, and compositional changes. This investigation aims to address this gap by exposing fly ash-blended cement paste to NaCl salt solution and carbonation. This study quantifies chloride desorption, monitors pH change, and analyze the compositional changes in pastes, including the measurement of Friedel's salt, portlandite, and calcite contents. Samples were first exposed to NaCl solution for 35 days and then 4 weeks of accelerated carbonation, during which their pH and composition at different depths were monitored. XRD and TGA tests were utilized to identify and quantify the main phases. The results show that carbonation reduced the pH from 13 to nearly 11 in OPC pastes and 10 in fly ash pastes. The inclusion of 15 % fly ash led to weakened carbonation resistance compared to OPC. After combined exposure to the salt solution and carbonation, the calcite content, representing carbonation, in fly ash pastes significantly increased by 190.9 % after one week carbonation and 282.1 % after two weeks of accelerated carbonation. Friedel's salt content, indicating bound chloride, dropped by roughly 78 % in OPC paste and 87 % in fly ash paste after one week of carbonation and completely dissolved after two weeks of carbonation. The results emphasize the importance of considering chloride desorption, similar to chloride binding, which has been incorporated into service life models. This negligence can lead to an overestimation of the service life of concrete infrastructures.

Apparent Influence of Anhydrite in High-Calcium Fly Ash on Compressive Strength of Concrete

This case study investigates five fly ashes with high CaO and SO3 levels in their chemical composition and compares the apparent influence of the presence and absence of anhydrite on compressive strength. Another distinguishing feature of the above ashes is that they, more or less, naturally contain anhydrite. Two different series of mixed proportions were adopted. Series 1 is designed to understand the maximum possible replacement level of fly ash. Series 2 is designed to understand the effect of anhydrite on compressive strength development. The mineral composition and glass phase of fly ashes were determined by X-ray diffraction Rietveld analysis. As a result of this study, we have found that concrete containing anhydrite-rich fly ash exhibits a higher strength than concrete containing anhydrite-free fly ash at all ages. The compressive strength increases with an increasing fly ash replacement ratio when anhydrite-rich ash is used, but strength decreases when the replacement level exceeds a certain point. The optimal amount of anhydrite was 2 ± 0.5 kg/m3 of concrete, excluding the anhydrite contained in cement.

The Effect of chlorine and glass additives on heavy metal volatilization during vitrification of simulated Municipal Solid Waste Incineration fly ash

This study examines the impact of chlorine and glass additives (SiO2 and B2O3) on heavy metal volatilization during vitrification of simulated Municipal Solid Waste Incineration (MSWI) fly ashes. Different simulated MSWI fly ash compositions were subjected to chloride volatilization, revealing that treating MSWI fly ash with Cl increases heavy metal volatilization especially Pb and Cu to about 40% and 20% respectively. Incorporating glass additives into fly ash with chlorine increases Pb volatilization by almost 80%, and Cu by 50%, and enables non-volatile Cd and Zn to vaporize.

Immobilization of heavy metals with chlorine and liquid phase formation during thermal treatment of MSWI fly ash

Due to effective detoxification, thermal treatment is a preferred treatment technology of municipal solid waste incineration (MSWI) fly ash. However, immobilization behavior of heavy metals during thermal treatment is unclear. In this work, a circulated fluidized bed fly ash with SiO2 addition and a grate furnace fly ash with high silica-aluminum coal ash addition were used to investigate combined effect of active chlorine content, liquid polymerization degree, temperature of initial liquid phase formation and liquid phase formation rate on the immobilization ratios of Zn, Pb and Cd by principle component analysis (PCA). The results show that the decrease in active chlorine content favors the immobilization of Zn, Pb and Cd because chlorination volatilization is reduced. Both the increase in liquid polymerization degree and the formation of initial liquid phase at low temperature promote the immobilization of Zn, Pb and Cd for physical encapsulation. However, a rapid formation of liquid phase is not favorable for the immobilization of Zn, Pb and Cd, because transfer of heavy metals between crystals and liquid phase is impeded by high viscosity of liquid phase during fusion. The results can provide a reference for how to achieve the immobilization of heavy metals by adjusting the chemical composition of MSWI fly ash during thermal treatment.

Studies of the phase composition and ultrafine structure of the initial domestic raw materials of proppants

The results of the study of intracrystalline electric and magnetic fields in samples on 57Fe nuclei by the ultrafine method of the Mossbauer effect are considered. The source of gamma radiation was 57Co in the chromium matrix. The spectra of the samples were measured on 57Fe nuclei using the MS1104Em spectrometer in the mode of constant accelerations at room temperature for absorption. The crystal structure, phase composition, and electronic states of individual components of the proppants are given. The measurements were carried out on the d8 Advance universal complex (Bruker, Germany). The data of parameters recorded on detectors of secondary energy characteristics of X-rays corresponding to K, L, M, N and O levels of electronic transitions using computer processing of elemental compositions and their ratios in samples are analyzed. The data of X-ray studies of the composition of fly ash are presented, determining its potential application in various industries, including the production of proppants. The results of the analysis of the chemical composition of bauxite samples obtained by X-ray diffraction analysis are presented. The silicon modulus (µSi) has been determined, which is the ratio of Al2O3 to SiO2 to characterize the quality of bauxite. The main components of bauxite were Al2O3 (aluminum oxide) and SiO2 (silicon dioxide). A significant content of Fe2O3 (iron oxide) was also noted, which is 24-33 wt. % for bauxite.

Compressive Strength Study on Reactive Powder Concrete with 30% Quartz Sand and Variations in Fly Ash Composition as Partial Substitution of Cement

The concrete industry is considered environmentally unfriendly and unsustainable due to the significant consumption of natural materials. Currently, the industry predominantly uses Portland cement as its main ingredient, leading to an increase in Portland cement production. However, the use of fly ash can help make the concrete industry more sustainable in the future. Fly ash can be used as a partial replacement for Portland cement in concrete production. This study aims to determine the effect of fly ash variations on the compressive strength of reactive powder concrete. The research method used is experimental. The concrete mix design includes 30% quartz sand and fly ash variations of 0%, 5%, 10%, 15%, 20%, and 25%. The compressive strength test specimens are cylindrical with a diameter of 7.5 cm and a height of 15 cm. The resulting test specimens have a compressive strength of more than 41.4 MPa, thus qualifying as high-strength concrete. The compressive strength test results for fly ash variations of 0%, 5%, 10%, 15%, 20%, and 25% are 62.62 MPa, 66.27 MPa, 75.59 MPa, 68.78 MPa, 66.21 MPa, and 63.70 MPa, respectively.

Mix design determination procedure for geopolymer concrete based on target strength method

This study presents the development and validation of a mix design determination procedure for geopolymer concrete to achieve the desired compressive strength. The procedure integrates artificial neural network (ANN) model developed based on a comprehensive data base from literature, data clustering, and parameter optimization techniques to enhance accuracy and reliability. Experimental validation is undertaken to demonstrate the mix design determination procedure’s capability to accurately predict mix designs for geopolymer concrete based on the target compressive strength, validating its efficacy for mix proportion determination. The integration of chemical oxide content in fly ash, curing time, curing temperature, and activator properties results in a 15.9% improvement in prediction accuracy for the training dataset and a 68.3% enhancement for the testing dataset, compared to the base ANN model that includes only the weight of fly ash and activator properties. Employing data clustering techniques enables the identification of prior estimates for the mix design parameters related to specific fly ash types and target compressive strength, streamlining the mix design process by analyzing pertinent data subsets. Parameter optimization ensures refined mix proportions, achieving the desired target strength economically while minimizing material waste and cost. The development of a user interface facilitates easy manipulation of mix designs, catering to users of varying expertise levels. Additional options for deeper insights into geopolymer concrete characteristics can be integrated into the mix design determination procedure. To assess the mix design determination procedure's ability to generalize effectively, a variety of fly ash samples with distinct chemical compositions were utilized, differing from those already present in the database. This approach allows for a thorough evaluation of the mix design determination procedure's performance when presented with fly ash compositions it has not encountered before. By doing so, this provides insights into the adaptability of the mix design determination procedure beyond the limitations of the training and testing datasets.

SURFACE MODIFICATION OF FLY ASH FROM ASAM-ASAM COAL POWER PLANT USING STEARIC ACID AS HYDROPHOBIC INORGANIC MATERIAL

Abundant coal reserves make this material a substitute fuel choice, especially for industry. The use of coal carries a high risk due to incomplete combustion and produces fly ash products. Fly ash cause pollution and health risks as well as environmental contamination when they are released, deposited, or leached into the ecosystem over short or long periods of time. The high content of silica and alumina in fly ash can be utilized and modified into new materials with added value. This research aims to modify the surface of fly ash using stearic acid as a hydrophobic inorganic material. Fly ash from Asam-asam Coal Power Plant was characterized by using XRD and modified by immersing in stearic acid (2,4,6, and 8%) and 98% ethanol. The result showed that the contact angle increases when fly ash is modified on the surface using stearic acid. The contact angle increases with increasing stearic acid concentration. The highest contact angle was obtained at a stearic acid concentration of 8%, and the lowest at 2% was about 112.9 and 102.2, respectively. The fly ash composition was primarily silica and alumina, which were crystalline, as confirmed by XRD. These findings provide several aspects of fly ash and its potential as a candidate material for environmental remediation and waste management.

Properties of products obtained in the process of solidification and stabilization of fly ash resulting from thermal treatment of sewage sludge

The article presents an analysis of the results of research on the composition of fly ash from the thermal processing of sewage sludge [SSA] collected from three incineration plants located in Warsaw, Cracow and Łódź. It determines the leaching values of selected heavy metals from the tested fly ash and ordinary class concrete C20/25 with partial replacement - up to 20% of cement with fly ash. The laboratory tests performed showed that they have a comparable granulometric composition. In contrast, the physico-chemical properties of the tested fly ashes differ from ashes from coal combustion traditionally used in concrete technology. SSA is characterized by an average lower content of silicon, iron, and aluminium oxides with a much higher content of phosphorus oxides. Leaching tests indicate low mobility of heavy metals, meeting Polish regulations regarding the possibility of using SSA in construction for specific applications. At the same time, they do not pose a significant threat to human health or the environment. Construction waste containing SSA may be disposed of in inert waste landfills.

Compressive Strength and Water Absorption Capacity on Brick Interlock with Fly Ash Addition

Interlock brick is an environmentally friendly substitute for house wall materials because the manufacturing process is not burned like red brick. This method of installing interlocking walls, like Lego, can function as a structure for sluice gates, columns and ring beams without the need for plastering or painting, so it is more effective and efficient and can reduce cement consumption. Several actions must be taken to minimize the use of cement by using environmentally friendly materials. One of the environmentally friendly materials that will be researched is Interlock bricks made from a mixture of Fly Ash . This research aims to determine the compressive strength and water absorption capacity of Interlock bricks mixed with Fly Ash. The research method begins by looking for interlock brick parameter data in the form of compressive strength and water absorption capacity. Compressive strength is a parameter of the mechanical suitability of interlock bricks , while water absorption is the ability of a material to absorb water. There are 3 variations of the mixture, namely with the ratio Fly Ash : Sand: Cement, mixture I (3: 3: 1) Fly Ash 43% , mixture II (4 : 3 : 1) Fly Ash 50% , and mixture III (5 : 3 : 1) Fly Ash 56% calculation divided based on the percentage of the amount of Fly Ash , obtained the compressive strength value of Interlock brick from the Fly Ash mixture in mixture I 16.0 kg/m2 and water absorption capacity 20%, mixture II 24.7 kg/m 2 and strength water absorption 17.5%, mixture III 10.3 kg/m 2 and water absorption 21.8%. According to SK-SNI-S-04-1989-F Interlock brick mix II with a Fly Ash composition of 50% is close to class K25 (25 kg/m 2 ) and has an absorption capacity value of <20.0% according to the absorption capacity limit based on SNI 15- 2094-2000.Keywords: Interlock Bricks, Fly Ash, Compressive Strength, Water Absorption.

Geotechnical Properties of Fly Ash Blended Expansive Soil: A Review

Fly ash, an industrial byproduct, is used as both a building material and a soil stabilizer due to its pozzolanic properties. Moreover, it is challenging to extrapolate the results based on an inadequate amount of laboratory data because of the non-homogeneous character of the soil and the diversity in the chemical properties of fly ash. This review article fills in the gaps by providing an overview of the existing data related to the geotechnical characteristics of expansive soil stabilized with fly ash. The chemical composition of fly ash is provided in terms of oxides of various elements to help identify the kinds produced in different nations. Additionally, information about the physical and geotechnical characteristics of fly ash blended expansive soil is provided in order to comprehend the influence of the fly ash's chemical composition and the expansive soil's fines percentage. While the geotechnical property comprises Atterberg's limit, compaction, UCS, shear strength, free swelling index, CBR, and consolidation, the physical property includes specific gravity and durability. Shear modulus, damping ratio, and Poisson's ratio are used to describe the dynamic properties of the modified expansive soil. The published data in this field and the research gap will be identified by the researchers with the aid of this article. Doi: 10.28991/CEJ-SP2024-010-06 Full Text: PDF

Chemical and Thermal Analysis of Fly Ash-Reinforced Aluminum Matrix Composites (AMCs)

Fly ash has been utilized as a reinforcing material in the production of aluminum matrix composites, and in this investigation, Al-Si (LM6) fly ash composites were fabricated using the compocasting method. Various compositions of fly ash were incorporated into the samples (4, 5 and 6 wt%), and the preparation temperature ranged from 560 to 800°C. This study investigated the thermal (CTE and DTA) and chemical properties (XRD) of fly ash reinforcement and the aluminum melt in the composites. The results revealed that composites with 5 wt% of fly ash exhibited the lowest CTE value compared to those with 4 and 6 wt%. This observation was corroborated by XRD analysis, indicating a reaction between the fly ash particles and the aluminum melt. However, the DTA analysis did not find a significant impact of the addition of fly ash on the melting temperature of the prepared composites. In contrast, this study identified and investigated the existence of reaction effects between the fly ash particles and the aluminum melt.

Optimizing the Composition of Basalt and Heat Treatment of Fly Ash-Based Mullite Ceramics Using the Taguchi Method

The development of industrial activities has an impact on the increase in waste produced, and fly ash, aluminum dross, and basalt dust are no exception. This research studies the potential of these three materials as ceramic materials. Basalt dust from East Lampung was used as filler. The effect on the physical and mechanical properties of mullite (3Al<sub>2</sub>O<sub>3</sub>-2SiO<sub>2</sub>) ceramics was studied. The manufacture of mullite ceramics based on Taguchi design includes fly ash compositions of 40%, 50%, and 60% and basalt content of 0%, 5%, and 10%. sintering temperatures of 600°C, 900°C, and 1,200°C. Taguchi and Anova were used to determine the effect of independent variables on hardness and density. In addition, macro and microphoto tests were carried out to determine the physical and topographic changes of mullite ceramics. Chemical composition tests with X-ray fluorescence were carried out on raw materials and ceramics that have been formed. Changes in the crystal phase in mullite ceramics were studied through the X-ray diffragment test. XRF test results obtained for raw fly ash (SiO<sub>2</sub> + Al<sub>2</sub>O<sub>3</sub> + Fe<sub>2</sub>O<sub>3</sub>): 84.84 wt%. The composition of raw basalt is predominantly 48.42% SiO<sub>2</sub>, 18.82% Al<sub>2</sub>O<sub>3</sub>, 12.60% Fe<sub>2</sub>O<sub>3</sub>, and raw aluminum dross with 67.821% Al<sub>2</sub>O<sub>3</sub> content. The mullite ceramic specimen consists of 38.24–45.30% SiO<sub>2</sub>, 34.72–48.73% Al<sub>2</sub>O<sub>3</sub>, 6.3–9.99% Fe<sub>2</sub>O<sub>3</sub>, and 2.31–5.31% CaO. The crystal phases formed are mullite, pyroxene, and diopside. Analysis of variance shows that hardness is significantly affected by sintering temperature, with a P-value of 0.013 and a contribution of 93.77%. This modeling is acceptable with an error value of 1.26%, or R-sq: 98.74%. The addition of basalt increases the density of mullite ceramics, with a P-value of 0.033 and a contribution of 96.05%. The addition of basalt as a filler is not able to increase the hardness significantly, but it affects the higher ceramic density value. However, the formation of mullite is interesting to study further as a refractory material

Utilization of fly ash and bottom ash from TanjungJati B Coal-Fired Power Plant in Jepara, Central Java, on the quality of cellular lightweight concrete

The research aims to address waste-related issues by producing Cellular Lightweight Concrete (CLC) bricks using fly ash and bottom ash as fine aggregates. The variations used encompass cement, fly ash, bottom ash, and sand compositions. The ratio between cement and fine aggregates utilized is 1:3. The variations in the composition of fine aggregates include P (100% sand), F (100% fly ash), B (100% bottom ash), F1B1 (50% fly ash and 50% bottom ash), F1B2 (33.3% fly ash and 66.7% bottom ash), F1B3 (25% fly ash and 75% bottom ash), F2B1 (6.7% fly ash and 33.3% bottom ash), and F3B1 (25% fly ash and 75% bottom ash). The parameters employed comprise compressive strength testing, density, and water absorption evaluation of the CLC bricks at ages 14, 28, and 35 days, also thermal conductivity at the 35-days sample. The sample age exhibits a proportional relationship with compressive strength and water absorption, while displaying an inverse relationship with density. At the 35-day sample age, the F composition demonstrates the highest compressive strength (14.74MPa) and the lowest water absorption (11%). Meanwhile, the B composition exhibits a compressive strength value of 5.9MPa and the lowest density (1.12g/cm2). Conversely, the P composition showcases the highest density (1.59g/cm2). Density affects thermal conductivity, the lower the density, the lower the thermal conductivity, which means that the heat conductivity will be smaller.

Sustainable production of eco-friendly roofing tile using methyl ester residue as the alternative binder – A preliminary study

Making full use of industrial by-products is an effort to achieve ‘zero waste’ and promote greener development. Methyl ester residue (MER) is a waste commonly found in oleochemical manufacturers, such as palm oil mills. Contrary to conventional cement and clay, MER was employed as an alternative binder to fabricate a novel eco-friendly roofing tile, henceforth referred to as MER-RT. Parameters tested were transverse strength, water absorption, sulfate resistance, and fire resistance. During the optimization phase, a range of 6–11% of MER was mixed with a fixed composition of fly ash and fine sand, compacted and cured at 190° C for 12–48 hours. Considering the electrical energy consumption, the optimal curing duration chosen was 24 hours as this MER-RT achieved a dry transverse strength of 4112 N whereas curing for an additional 18 hours further contributed to only 16% strength gain. The optimal MER-RT was found to contain 10% MER as it showed the highest dry transverse strength (6410 N), the highest wet transverse strength (3681 N) and the lowest water absorption percentage (2.67%), meeting the American Society for Testing and Materials (ASTM) standards. Besides exhibiting minimal corrosion under the sodium sulfate test, the optimal MER-RT was non-flammable and did not undergo structural changes when exposed to fire. The study reveals the potential of both MER and fly ash as green binders and fillers for roof tiles, despite their origins as industrial waste.

Influence of recycled coarse aggregate on properties of fly ash and slag-based geopolymer concrete cured under oven and ambient temperature

Purpose The purpose of this paper is to investigate the effect of the replacement of natural coarse aggregate (NCA) with different percentages of recycled coarse aggregate (RCA) on properties of low calcium fly ash (FA)-based geopolymer concrete (GPC) cured at oven temperature. Further, this paper aims to study the effect of partial replacement of FA by ground granulated blast slag (GGBS) in GPC made with both NCA and RCA cured under ambient temperature curing. Design/methodology/approach M25 grade of ordinary Portland cement (OPC) concrete was designed according to IS: 10262-2019 with 100% NCA as control concrete. Since no standard guidelines are available in the literature for GPC, the same mix proportion was adopted for the GPC by replacing the OPC with 100% FA and W/C ratio by alkalinity/binder ratio. All FA-based GPC mixes were prepared with 12 M of sodium hydroxide (NaOH) and an alkalinity ratio, i.e. sodium hydroxide to sodium silicate (NaOH:Na2SiO3) of 1:1.5, subjected to 90°C temperature for 48 h of curing. The NCA were replaced with 50% and 100% RCA in both OPC and GPC mixes. Further, FA was partially replaced with 15% GGBS in GPC made with the above percentages of NCA and RCA, and they were given ambient temperature curing with the same molarity of NaOH and alkalinity ratio. Findings The workability, compressive strength, split tensile strength, flexural strength, water absorption, density, volume of voids and rebound hammer value of all the mixes were studied. Further, the relationship between compressive strength and other mechanical properties of GPC mixes were established and compared with the well-established relationships available for conventional concrete. From the experimental results, it is found that the compressive strength of GPC under ambient curing condition at 28 days with 100% NCA, 50% RCA and 100% RCA were, respectively, 14.8%, 12.85% and 17.76% higher than those of OPC concrete. Further, it is found that 85% FA and 15% GGBS-based GPC with RCA under ambient curing shown superior performance than OPC concrete and FA-based GPC cured under oven curing. Research limitations/implications The scope of the present paper is limited to replace the FA by 15% GGBS. Further, only 50% and 100% RCA are used in place of natural aggregate. However, in future study, the replacement of FA by different amounts of GGBS (20%, 25%, 30% and 35%) may be tried to decide the optimum utilisation of GGBS so that the applications of GPC can be widely used in cast in situ applications, i.e. under ambient curing condition. Further, in the present study, the natural aggregate is replaced with only 50% and 100% RCA in GPC. However, further investigations may be carried out by considering different percentages between 50 and 100 with the optimum compositions of FA and GGBS to enhance the use of RCA in GPC applications. The present study is further limited to only the mechanical properties and a few other properties of GPC. For wider use of GPC under ambient curing conditions, the structural performance of GPC needs to be understood. Therefore, the structural performance of GPC subjected to different loadings under ambient curing with RCA to be investigated in future study. Originality/value The replacement percentage of natural aggregate by RCA may be further enhanced to 50% in GPC under ambient curing condition without compromising on the mechanical properties of concrete. This may be a good alternative for OPC and natural aggregate to reduce pollution and leads sustainability in the construction.

Analysis Stability Of Asphalt Concrete Binder Course (AC-BC) With Fly Ash And Bottom Ash Substitution Material

Fly ash and bottom ash are ash produced from the process of burning coal as a source of energy in the steam generating unit of a coal-fired power plant (PLTU). Bottom ash is ash that forms at the bottom of a coal-burning furnace and settles there. In this research, fly ash is used as filler substitution and bottom ash is used as fine aggregate substitution (sand). The purpose of the study was to obtain a suitable Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials. To determine the effect of optimum asphalt content on the values of stability, flow, Marshall Quotient, VMA, VIM and VFB obtained from result of the Masrhall test. Based on the results of Marshall testing, the results show that Analysis Stability Of Binder Course Asphalt Concrete (AC-BC) With Fly Ash And Bottom Ash Substitution Material produces the highest VMA value of 14.462% and the highest VIM value of -1.88%, meaning that there are many gaps in the mixture containing asphalt so that it becomes waterproof and hermetic. The highest stability and MQ values are stability of 1955.55.34 kg and MQ of 1241.13 kg/mm. The appropriate Job Mix Design (JMD) for Asphalt Concrete - Binder Course (AC-BC) with fly ash and bottom ash substitution materials is the composition of Fly Ash at 0%, 50%, and 60% of the total cement while for the use of Bottom Ash from the total sand at 0%, 50%, and 60%.