Coal Bottom Ash Research Articles

Use of waste recycling coal bottom ash and sugarcane bagasse ash as cement and sand replacement material to produce sustainable concrete.

Concrete is widely used as a building material all over the world, and its use is increasing the demand of cement and sand in the construction industry. However, the limited resources and environmental degradation are driving scientists to develop alternative materials from vast volumes of agro-industrial wastes as a partial replacement for conventional cement. In the manufacture of concrete, cement is a major binding resource. This study looked into recycling agro-industrial wastes into cement, such as sugarcane bagasse ash (SCBA), coal bottom ash (CBA), and others, to create sustainable and environmentally friendly concrete. This study aims to see how the combined effects of agricultural by-product wastes affected the characteristics of concrete. SCBA is used to replace fine aggregate (FA) ranging from 0 to 40% by weight of FA, while CBA is used to replace cement content ranging from 0 to 20% by weight of the total binder. In this case, a total of 204 concrete samples (cubes and cylinders) are made using a mixed proportion of 1:1.5:3 and a water-cement ratio of 0.54. Workability, density, water absorption, and mechanical characteristics in terms of compressive and splitting tensile strengths were examined in this study. In addition, for each mix percentage, the total embodied carbon was determined. Workability, density, and water absorption were found to be considerably decreased when CBA and SCBA concentration increased. Due to the pozzolanic nature of CBA and SCBA, an increase in compressive and splitting tensile strengths were seen for specific concrete mixtures, and further addition of CBA and SCBA, the decrease in strength. The embodied carbon of SCBA has augmented the total embodied carbon of concrete, though it can be seen that C15S40, which comprises of 15% CBA and 40% SCBA, is the optimum mix that attained tensile and compressive strength by 3.05MPa and 28.75MPa correspondingly, with a 4% reduction in total embodied carbon.

Effect of Coal Bottom Ash as Partial Sand Replacement for Lightweight Aggregate Concrete

Environmental degradation due to disposal of waste namely coal bottom ash waste from thermal power plant, clinker waste of palm oil mill and river sand mining activity for concrete production need to be resolved. Palm oil clinker lightweight concrete with zero granite aggregate that been produced in effort to reduce dependency of natural stone consumption has been further explored its potential in this research. Thus, the present research investigates the compressive strength, water absorption and acid resistance of lightweight aggregate concrete containing coal bottom ash as partial sand replacement. Five types of concrete mixes were produced using 0%, 10%, 20%, 30% and 40% coal bottom ash as fine aggregate replacement. After curing process, specimens were immersed in acid hydrochloric solution before subjected to compressive strength testing. Findings show that all specimen experience strength reduction after exposed to acidic environment. On overall, the use of coal bottom ash influences the durability performance of lightweight aggregate concrete.

The Influence of Coal Bottom Ash as Filler in Asphalt Mixture

The number of transport or vehicles on the road is increasing, which cause the road pavement or asphalt surface exposed to greater loading. Problems such as permanent deformation, cracking, fatigue, and skidding happened because of this repeated loading. There are many studies have been done to determine the suitable waste materials that can be used in order to improve resistance to rutting and fatigue cracking due to filler hardening and improve adhesion of filler to aggregate. The aim of this study is to investigate the effect of CBA on engineering properties of asphalt mixture. The different percentages of CBA (0%, 2%, 4% and 6%) were added to the asphalt mixture. The 60/70 penetration grade asphalt was used. The performance of the samples was evaluated through Marshall Stability, indirect tensile strength, resilient modulus, dynamic creep and image analysis. From the result obtained, there are significant effect comes from the addition of CBA. The result show that the addition of CBA in range of 2 to 4% produces the best outcomes for the density, stability, stiffness and flow while 6% for indirect tensile strength, dynamic creep and resilient modulus. Thus, it can conclude that the existence of CBA can enhance the performance of asphalt mix.

“Feasibility of waste copper slag with coal bottom ash in concrete as partial substitution of fine aggregate”

“Feasibility of waste copper slag with coal bottom ash in concrete as partial substitution of fine aggregate”

Effect of Waste Fines and Fibers on the Strength and Durability Performance of Silica Fume Based Reactive Powder Concrete

The demand and consumption of conventional concrete materials is increasing day by day, which in turn leads to the extinction of natural resources. Certain researchers tend to draw a circle to solve this global problem by finding alternative materials satisfying all aspects, mainly efficiency, eco-friendly and economical. The present research work aimed to study the combined use of coal bottom ash (CBA) and waste concrete powder (WCP) in silica fume based reactive powder concrete (SF-RPC) subjected to thermal curing. The replacement of cement by silica fume was limited to 20% and the fine aggregate quartz sand replaced by CBA and WCP varied from 5% to 25% each. The material composition of SF-RPC involves the exclusion of coarse aggregates and the inclusion of finer materials with micro-steel fibers. The steel fibers played a significant role in order to obtain a ductile and stable product of SF-RPC. The experimental investigation on SF-RPC comprised of the determination of fresh concrete properties such as slump flow and the compaction factor, as well as mechanical properties like compressive strength, flexural strength and split-tensile strength. The study was also extended to investigate durability properties such as water absorption, sorptivity and resistance to acid attack. The results showed that silica fume proves to be a feasible alternative to partially replace cement and also that optimum incorporation of pre-treated and processed CBA and WCP attains better mechanical and durability performance without compromising the necessary qualities.

Investigation on Mechanical and Durability Properties of Concrete Mixed with Silica Fume as Cementitious Material and Coal Bottom Ash as Fine Aggregate Replacement Material

Cement production produces a high amount of carbon dioxide, which has a negative impact on the environment. By utilizing waste products instead of cement, environmental degradation can be reduced. The current study was undertaken to study the mechanical and durability performance of concrete by replacing 7.5%, 10%, and 12.5% silica fume (SF) of cement weight. Additionally, coal bottom ash (CBA) was also substituted as fine aggregates with 10%, 20%, and 30%. Compressive strength and indirect tensile strength were the major parameters regarding mechanical properties, while corrosion analysis and sulfate attack were set for durability performance. Sixteen mixes were prepared including a control mix. Out of these, three mixes contained SF, three mixes contained CBA, and eight mixes contained both SF and CBA with 1:2:4 ratio at 0.5 w/b ratio. The results concluded that the addition of 12.5% SF and 30% CBA gives optimum compressive strength and tensile strength. Furthermore, using the SF and CBA reduces the workability of concrete. Furthermore, the use of these byproducts increased the durability in terms of corrosion and sulfate attack.

Reviewing mechanical performance of geopolymer concrete containing coal bottom ash

Concrete is one of the most demanding construction materials and also the third-largest emitter of greenhouse gases on the planet. Likewise, cement is a commonly used binder in concrete and its production accounts for nearly 7 percent of global greenhouse gasses resulting it into one of the most non-sustainable options. Geopolymer concrete (GPC) is a type of construction material made with the utilization of the waste products of industries (like fly ash, copper slag, coal bottom ash, etc.). It comprises the process of geopolymerisation with the help of alkali activators particularly made of sodium hydroxide and sodium silicate. Further, Coal Bottom ash (CBA), generated from thermal power plants is generally landfilled and has already created serious threats to the environment. The current review summarizes the present and past research trends of mechanical behavior of GPC made with different amounts of CBA either used as replacement of binder or as fine aggregates. Generally, the mechanical properties of GPC depend on various parameters like alkali solution content, liquid/binder ratio, molarity of NaOH, NS/NH ratio, grinding of CBA and type of curing. The literature indicates that, an increase in various parameters such as NS/NH ratio (1.5–4.9), molarity of NaOH (10 M−16 M) and the grinding period (12 h–36 h) improves the overall mechanical properties. Likewise, an increase in liquid/binder ratio (0.5–1) and alkali content reduces the strength properties of CBA based GPC at different curing regimes. The findings also suggest the adequate potential of CBA to be used as primary/secondary material in Geopolymer concrete. Last, the study briefly highlights the challenges and future scope of application of CBA in developing GPC.

Assessment of the impact of adding fly ash and coal bottom ash to an advanced cement-based composite matrix

Abstract To reduce environmental impact and hydration heat from high cement consumption in advanced cement-based composites, this study proposes the partial cement substitution by fly ash (FA) and coal bottom ash (CBA) in rates of 15% by mass (7.5% FA and 7.5% CBA) and 30% by mass (15% FA and 15% CBA). Matrixes were assessed for their physical and mechanical characteristics though the tests of compressive strength, capillary water absorption and ultrasonic pulse velocity, added to the analysis of images generated by scanning electron microscopy (SEM) and energy-dispersive X-ray spectroscopy (EDS). Results indicated better performance of fly ash due to its particle size, shape and texture, especially for the rate of 15%. In terms of compressive strength, mixture RFA15 yielded the highest strength. The capillary water absorption results were linear and with low variations of about 1% and 5% between 28 and 56 days.

Investigation on wear characteristics of Al 2219/Si3N4/Coal bottom ash MMC

High-energy ball milling is used to create nanostructured materials from coal bottom ash (CBA) and silicon nitride (Si3N4). 36 h of ball milling coal bottom ash reduced it to 51.3 nm, while silicon nitride was reduced from 61.2 nm to 29 nm. Metal Matrix Composites (MMC) is fabricated through liquid stir method. The composites wear rate went up with nano coal bottom ash and nano silicon nitride reinforcementsdue to clustering, as well as a lack of interfacial connection between the base material and hybrid reinforcements employed. Increased frictional drive causes magnified debonding and easy exclusion of composite particles, accelerating the amount of wear. The friction coefficient reduces in all composite configurations as the average load increases.

Performance of coal bottom ash concrete at elevated temperatures

Nowadays, the recycling of waste materials produced in the industry has become a significant issue. Natural sand is the important material for preparing concrete mix design. Due to the large excavation of river sand, erosion is taking place, and it's a big environmental issue. New material needs to be found as replacement of natural sand, as there is a huge shortage of natural sand now a days. It is necessary to have good material that is a good replacement for natural sand that can withstand fire. This study emphasizes concrete's physical and mechanical properties by substituting 30% natural fine aggregates by coal bottom ash. Coal bottom ash concrete and normal concrete subjected to the elevated temperature of 100, 200, 400, 600, 800°Celsius for the time of one hour. The physical properties like color change and mass change concerning the temperature also studied. Concrete in which CBA partially replaces fine aggregates retains good strength as reference concrete.

Engineering Properties of Concrete Made with Coal Bottom Ash as Sustainable Construction Materials

Concrete is considered one of the construction materials that contribute the most significant carbon dioxide in the world. Meanwhile, according to various studies, concrete production will continue to rise through 2050, especially in developing countries. According to several reports, cement manufacture is one of the largest sources of carbon dioxide in the concrete sector. In addition, overexploitation of aggregates due to concrete production also causes unavoidable natural damage. Bottom ash waste was used as a replacement for cement and fine aggregate as sustainable construction materials. It is envisaged that this research would allow industrial waste to be utilized to its full potential, resulting in a concrete that is more environmentally friendly and minimizes carbon dioxide emissions during the manufacturing process. This study is divided into bottom ash as a cement substitute and bottom ash as a fine aggregate substitute. The engineering properties of the concrete were checked during the experiments in this study when it was fresh and hardened states. The slump test is used to determine the workability of fresh concrete. While for the hardened properties tests consist of compressive strength, splitting tensile strength, flexural strength, and mass density. The usage of bottom ash as a cement replacement demonstrates that as the composition of bottom ash increases, the performance of the hardened properties of concrete decreases. While using bottom ash as a fine aggregate replacement reveals that the performance of hardened properties has improved as the proportion of bottom ash utilized has increased. Doi: 10.28991/CEJ-2022-08-01-014 Full Text: PDF

Coal Bottom Ash with Addition of Fly Ash Concrete: Mechanical Properties and Cracking Mechanism of Concrete Subjected to Simplified Cyclic Load Test

Coal Bottom Ash with Addition of Fly Ash Concrete: Mechanical Properties and Cracking Mechanism of Concrete Subjected to Simplified Cyclic Load Test

Development of Sensible Heat Storage Materials Using Sand, Clay and Coal Bottom Ash

In this paper, the mechanical and thermal properties of a sand-clay ceramic with additives coal bottom ash (CBA) waste from incinerator coal power plant are investigated to develop an alternative material for thermal energy storage (TES). Ceramic balls are developed at 1000°C and 1060°C using sintering or firing method. The obtained ceramics were compressed with a compression machine and thermally analyse using Decagon devise KD2 Pro thermal analyser. A muffle furnace was also used for thermal cycling at 610°C. It was found that the CBA increased the porosity, which resulted in the increase of the axial tensile strength reaching 3.5 MPa for sand-clay and ash ceramic. The ceramic balls with the required tensile strength for TES were selected. Their volumetric heat capacity, and thermal conductivity range respectively from 2.4075 MJ·m-3·°C-1 to 3.426 MJ·m-3·°C-1 and their thermal conductivity from 0.331 Wm-1·K-1, to 1.014 Wm-1·K-1 depending on sand origin, size and firing temperature. The selected formulas have good thermal stability because the most fragile specimens after 60 thermal cycles did not present any cracks. These properties allow envisioning the use of the ceramic balls developed as filler material for thermocline thermal energy storage (structured beds) in Concentrating Solar Power plants. And for other applications like solar cooker and solar dryer.

On Guideline for Mix Proportioning of Concrete Incorporating Coal Bottom Ash as Fine Aggregate Bottom Ash as Fine Aggregate

On Guideline for Mix Proportioning of Concrete Incorporating Coal Bottom Ash as Fine Aggregate Bottom Ash as Fine Aggregate

Effects of fly and coal bottom ash ratio on backfill material performance

Fly ash (FA) and coal bottom ash (CBA) were selected to study the effects of their ratios on backfill materials. The rheological properties, stability, mechanical properties, crystal structure, and microstructure of backfill materials were investigated at different FA/CBA ratios. Increased FA/CBA values improved the slump, rheological performance, setting time, mechanical strength, and elastic modulus. However, the excellent water retention of CBA reduced the bleeding capacity, and the alkali-activated reaction by CBA generated a large amount of ettringite (AFt) that produced early strength. In the late period, the FA/CBA values affected the morphology and compactness of the calcium-silicate-hydrate gels. Furthermore, the performance of backfill materials with 0.5% superplasticizer and 30%-50% FA/CBA ratio could satisfy the requirements, and this formula has been applied to the filling mining project.

Study on mechanical properties of concrete inclusion of high-volume coal bottom ash with the addition of fly ash

Coal bottom ash (CBA) has been widely utilized in concrete production as a partial replacement for aggregate. Still, the massive amount of CBA generated every day ends up dumped at a landfill without economic value. Therefore, the aim of the study identified the influence of CBA as a coarse and fine aggregate replacement, in addition of fly ash (FA) as a partial cement substitution in concrete made. The experimental tests were carried out on the fresh and hardened state of concrete to evaluate the workability test, compression test, flexural test, and modulus of elasticity test. CBA was replaced in concrete by four different combination arrangements between half (50%) and full (100%) coarse and fine aggregate using the volume replacement method. Then, 20% of FA was substituted to the mass of cement as an additive cementitious material to enhance the pozzolanic reaction. The results revealed that a high amount of CBA in concrete contributed to the low workability of fresh concrete. The concrete made by 100% CBA as coarse and fine aggregate replacement produced better compressive strength than the control concrete. Besides, all replacement levels of CBA in concrete had a modulus of elasticity in the range of 5.07 to 5.67 GPa, which is acceptable for its compression strength of 30 to 35 MPa at 28 days. Besides, CBA concrete recorded a significant reduction in flexural strength with the increment level of percentage CBA in concrete mix ingredients. Therefore, the evaluation of the mechanical properties of concrete containing large volume CBA with the addition of FA shows good performance and has the potential to be utilized in concrete manufacturing.

Investigation on strength and failure behavior of ceramic foams prepared from silicoaluminous industrial waste under uniaxial compression

This paper experimentally investigated the compressive strength-porosity and compressive strength-bulk density dependence of ceramic foams fabricated using coal bottom ash (CBA), bauxite residue, and low-grade albite. The compressive stress-strain curves of ceramic foams with different bulk densities under pressure were compared to reveal the difference of their fracture mechanisms. The compressive strength-porosity trend of CBA foamed ceramics with a porosity range of 68-87% complied with the Rice model and could be expressed by an exponential equation σf=53852.28×exp-0.105P. However, for the porosity levels exceeding 90%, a linear equation σf=54.33-0.57P was provided the most accurate data fitting. The compressive strength-bulk density dependence of ceramic foams also satisfied the Gibson-Ashby model expressed by σf=73.54ρ∗3/2-26.64ρ∗. Finally, the variation of fracture mechanisms of compressed ceramic foams with their bulk density was revealed. Under one-dimensional compression stress, low-density ceramic foams (ρ ≤ 0.40 g/cm3) underwent plastic-like deformation, while high-density ones (ρ ≥ 0.60 g/cm3) exhibited brittle fracture behavior.

Analysis and Development of Coal Bottom Ash Used for Embankment Filling

Analysis and Development of Coal Bottom Ash Used for Embankment Filling

A Comparative Study on the Thermal Conductivity of Concrete with Coal Bottom Ash under Different Drying Conditions

The utilization of coal bottom ash (CBA) and fly ash in concrete has become more common. For CBA concrete, curing conditions would influence the thermal properties of the concrete due to the high water absorption capacity of the CBA aggregate. In addition, CBA and fly ash contents in concrete affect the thermal properties of the concrete. Therefore, the effects of the drying conditions and the CBA and fly ash contents on the thermal conductivity of CBA concrete were investigated in this study. The thermal conductivity of concrete was measured under two different curing and drying conditions: oven-dried conditions and saturated surface-dry (SSD) conditions, with curing times of 28 and 91 days. The concrete mixtures also contained different levels of CBA and fly ash. Crushed sand in the concrete mixtures was replaced by CBA with replacement ratios of 25%, 50%, 75%, and 100% by volume. In addition, cement in the concrete mixture was substituted by fly ash with replacement ratios of 20 and 40% by volume. The thermal conductivity of concrete under the oven-dried conditions was much lower than that under the SSD conditions. Moreover, the thermal conductivity of the concrete decreased as the CBA content increased under both the oven-dried and SSD conditions. The material properties of the concrete, including unit weight, compressive strength, and ultrasonic velocity, were also measured in the study. Compared with the SSD conditions, the compressive strength, unit weight, and ultrasonic velocity of CBA concrete were considerably lower under the oven-dried conditions. Moreover, the relationships between the thermal conductivity and unit weight, compressive strength, and ultrasonic velocity were suggested.

Characteristics and impact of aged coal ash with slag emplaced in a karst cave: the case of Diva\u0161ka jama, Slovenia

A mixture of coal bottom ash and slag, with a fraction of fly ash (CAFAS) from steam locomotives, was placed in the cave Divaška jama to delimit and level tourist trails. Emplacement began in 1914 and carried on for several decades. The CAFAS mixed with other cave material gradually changed its structure and appearance. Currently the concentration of some elements in the CAFAS (As, Cu, Hg, Ni, Pb, Zn), and also to a lesser extent in cave sediments (Cr, Cu, Ni), indicates a possibly harmful effect on sediment-associated biota based on ecotoxicological assays. Compared to the cave sediment, the CAFAS contains distinctly different mineral phases and presents a different source of radioactivity. Microbial metabolic activity of CAFAS is low, 0.22 μl O2/gDW h, but higher than that of cave sediment. The present environmental hazards from CAFAS are estimated to be low. Whereas the emplacement of CAFAS was seen initially a long-term solution for waste disposal and management of the cave, it turned out that CAFAS enriches the underground environment with inorganic and organic compounds and disperses pollution into the cave ecosystem. After its removal from the cave, the CAFAS should be investigated thoroughly due to its susceptibility to alteration.