scholarly journals Effects of Separated Fractions of Fbc Bottom Ash on Selected Properties of Cement Mortars

2020 ◽  
Vol 30 (4) ◽  
pp. 1-20
Author(s):  
Zbigniew Kledyński ◽  
Łukasz Krysiak
Keyword(s):  
Power Plants ◽  
Activity Index ◽  
Bottom Ash ◽  
High Water ◽  
Coarse Grained ◽  
Partial Replacement ◽  
Fine Grained ◽  
Cement Mortars ◽  
Inert Additive ◽  
High Silica

Abstract This paper discusses the effects of partial replacement of cement with fluidized bed bottom ash on the properties of mortars. The analyzed ash samples originating from four Polish power plants were separated by grain size selection into fine and coarse-grained fractions. This process leads to a creation of derivative samples of differing physical properties and, partially, phase compositions, as tested in XRD and TG analyses. Despite its high water demand, the obtained fine-grained fraction has the potential for application in cementbased composites as a reactive, pozzolanic additive. An acceptable activity index may be reached when the sulfate content is limited, implying benefits of combining the ash with low gypsum cements. The coarse-grained fraction is significantly less reactive, while a high silica and aluminate content is related to improved mechanical properties of the composite. It can, therefore, potentially be used as a quasi-inert additive or a substitute for sand.

scholarly journals Recycling Untreated Coal Bottom Ash with Added Value for Mitigating Alkali–Silica Reaction in Concrete: A Sustainable Approach

2020 ◽  
Vol 12 (24) ◽  
pp. 10631
Author(s):  
Safeer Abbas ◽  
Uzair Arshad ◽  
Wasim Abbass ◽  
Moncef L. Nehdi ◽  
Ali Ahmed
Keyword(s):  
Portland Cement ◽  
Power Plants ◽  
Activity Index ◽  
Bottom Ash ◽  
Pozzolanic Activity ◽  
Added Value ◽  
Partial Replacement ◽  
Alkali Silica Reaction ◽  
Coal Bottom Ash ◽  
Limit Value

Each year, about 730 million tons of bottom ash is generated in coal fired power plants worldwide. This by-product can be used as partial replacement for Portland cement, favoring resource conservation and sustainability. Substantial research has explored treated and processed coal bottom ash (CBA) for possible use in the construction industry. The present research explores using local untreated and raw CBA in mitigating the alkali–silica reaction (ASR) of reactive aggregates in concrete. Mortar bar specimens incorporating various proportions of untreated CBA were tested in accordance with ASTM C1260 up to 150 days. Strength activity index (SAI) and thermal analysis were used to assess the pozzolanic activity of CBA. Specimens incorporating 20% CBA achieved SAI greater than 75%, indicating pozzolanic activity. Mixtures incorporating CBA had decreased ASR expansion. Incorporating 20% CBA in mixtures yielded 28-day ASR expansion of less than the ASTM C1260 limit value of 0.20%. Scanning electron microscopy depicted ASR induced microcracks in control specimens, while specimens incorporating CBA exhibited no microcracking. Moreover, low calcium-to-silica ratio and reduced alkali content were observed in specimens incorporating CBA owing to alkali dilution and absorption, consequently decreasing ASR expansion. The toxicity characteristics of CBA indicated the presence of heavy metals below the US-EPA limits. Therefore, using local untreated CBA in concrete as partial replacement for Portland cement can be a non-hazardous alternative for reducing the environmental overburden of cement production and CBA disposal, with the added benefit of mitigating ASR expansion and its associated costly damage, leading to sustainable infrastructure.

scholarly journals Utilizing Coal Bottom Ash from Thermal Power Plants in Vietnam as Partial Replacement of Aggregates in Concrete Pavement

2019 ◽  
Vol 2019 ◽  
pp. 1-11
Author(s):  
Nu Nguyen Thi ◽  
Thinh Phi Hong ◽  
Son Bui Truong
Keyword(s):  
Power Plants ◽  
Cement Content ◽  
Thermal Power ◽  
Bottom Ash ◽  
Concrete Pavement ◽  
Partial Replacement ◽  
Technical Requirement ◽  
Thermal Power Plants ◽  
Rural Roads ◽  
Flexural Tensile Strength

In Vietnam, a large amount of coal bottom ash (CBA) is being discharged from thermal power plants and has been making serious environmental pollution. It is essential to utilize the CBA to reduce environmental pollution. So, this paper presents a series of experimental studies in the laboratory using CBA as a partial replacement of aggregates in concrete pavement for rural roads. In mixing concrete, the CBA is utilized to replace 15, 30, and 100% aggregates. The design of the composition must achieve the technical requirement of M-30 grade of concrete. A total 351 of specimens were tested on workability of fresh concrete, abrasion, compressive strength, and flexural tensile strength in order to achieve the technical requirement of concrete pavement for rural roads. Based on the experimental results, in order to achieve the required compressive strength, An Khanh CBA concrete uses more content of cement and water than control concrete; Cao Ngan CBA is only utilized to replace 15% aggregates, and Cao Ngan CBA concrete also uses more cement and water than control concrete. It also shown that the amount of water and cement content depend on types of CBA and the water amount and cement content of CBA concrete are larger than those of control concrete. The advantage of mixture CBA concrete is abrasion, and flexural tensile strength achieved the value as per the technical requirement.

scholarly journals Predicting the frost heaving of bottom ash value for road design

2020 ◽  
Vol 17 (5) ◽  
pp. 624-635
Author(s):  
A. A. Lunev ◽  
D. A. Razuvaev ◽  
V. V. Golubenko ◽  
M. G. Chakhlov
Keyword(s):  
Initial Moisture Content ◽  
Bottom Ash ◽  
Size Composition ◽  
Freezing Temperature ◽  
Coarse Grained ◽  
Joint Work ◽  
Frost Heaving ◽  
Fine Grained ◽  
Road Design ◽  
Northern Regions

Introduction. Most of the researchers dealing with the use of ash and slag materials (especially in the construction) have focused on the study of their mechanical characteristics or assessment of their impact on the environment. At the same time, the design of roads with embankments of soil materials in the Northern regions requires taking into account the behavior of materials in cold climates.Although ash and slag materials are a typical dispersed soil, it is prone to frost heaving (due to the peculiarities of the internal structure). In addition, these materials have not been sufficiently tested in the development of the Russian Federation standards and codes for road design. Therefore, the professional environment is developing a hypothesis about the inadmissibility of using ash and slag materials in road embankments due to excessive frost heaving of this material, which, in our opinion, is not the case.Methods of research. To obtain real values of ash and slag frost heaving, specialists of Siberian State Transport University carried out additional studies to determine the relative deformations of frost heaving of medium-grained samples and coarse-grained ash slabs. SibADI specialists compared the results obtained with earlier studies to determine the relative deformations of frost heaving of fine-grained ash slabs samples, and analyzed the entire array of data obtained.Results. As a result of joint work, an empirical model was obtained that makes it possible to predict the amount of frost heaving of ash and slag material depending on its degree of compaction, initial moisture content (when working in a closed circuit or moisture in freezing through an open system), particle size distribution and freezing temperature. This makes it possible to determine the degree of frost heaving of ash and slag systems based on the grain size composition and the calculated characteristics of the subgrade. 

Use of Spongilites as Pozzolanic Additives in Cement Mortars

2021 ◽  
Vol 325 ◽  
pp. 65-70
Author(s):  
Martin Vyšvařil ◽  
Patrik Bayer ◽  
Tomáš Žižlavský
Keyword(s):  
Mechanical Properties ◽  
Bulk Density ◽  
Frost Resistance ◽  
Water Retention ◽  
Cement Mortar ◽  
Partial Replacement ◽  
Fine Grained ◽  
Natural Pozzolans ◽  
Cement Mortars ◽  
Pozzolanic Additives

In this study, the utilization of two types of spongilites in various addition in cement mortars has been investigated with the purpose of exploring a new application of this natural pozzolans as cement mortar additives. The influence of the addition of spongilites on the physico-mechanical properties, frost-resistance, and microstructure of cement mortars as a function of time was studied. The results revealed that the rising proportion of spongilites in cement mortars causes increase in water retention of mortars, reduction of their bulk density, increase in porosity of mortars due to the growing predominance of capillary pores maintaining sufficient mortars strengths, and slightly increase in the frost-resistance of mortars. After initial tests, partial replacement of cement in fine-grained cement mortars with hitherto unexploited spongilites seems to be very promising. Based on the achieved results, a 20% cement replacement can be recommended as optimal.

scholarly journals Penggunaan Abu Dasar Batubara Sebagai Pengganti Sebagian Agregat Halus pada Campuran Latasir B Terhadap Karakteristik Marshall

2015 ◽  
Vol 12 (2) ◽  
Author(s):  
Roza Gusman
Keyword(s):  
Power Plants ◽  
Thermal Power ◽  
Bottom Ash ◽  
Coal Ash ◽  
Asphalt Mixtures ◽  
Partial Replacement ◽  
Fine Aggregate ◽  
Coal Bottom Ash ◽  
Alternative Material ◽  
Total Proportion

Penggunaan Abu Dasar Batubara Sebagai Pengganti Sebagian Agregat Halus pada Campuran Latasir B Terhadap Karakteristik MarshallBasic Use of Coal Ash to Replace Some Fine Aggregate on Characteristics of Mixed Latasir B MarshallRoza Gusman1 & Alik Ansyori21,2Jurusan Teknik Sipil Fakultas Teknik – Universitas Muhammadiyah MalangAlamat korespondensi : Jalan Raya Tlogomas 246 Malang 65144AbstractCoal bottom ash is the residue from the burning of coal in thermal power plants. The use of coal bottom ash as an alternative material mix pavement is one way to take advantage of these residues. This study aimed to determine the effect of the use and the quantity of coal bottom ash as partial replacement of fine aggregate characteristics that meet the requirements for mixed marshall latasir B. Partial replacement of fine aggregate with coal bottom ash is made with a variation of 5%, 10%, 15%, 20%, 25%, 30%, and 35% of the total proportion of fine aggregate. Results of the study note that the use of coal bottom ash generally improves the quality mix latasir B. Latasir mixture B which has the characteristics of the best marshal is on the basis of coal ash content of 17.2%.Keywords: latasir B asphalt mixtures, coal bottom ash, marshall characteristics. AbstrakBottom ash batubara adalah residu dari pembakaran batubara di pembangkit listrik termal . Penggunaan batubara bawah abu sebagai alternatif campuran bahan perkerasan adalah salah satu cara untuk mengambil keuntungan dari residu tersebut . Penelitian ini bertujuan untuk mengetahui pengaruh penggunaan dan kuantitas bawah abu batubara sebagai pengganti parsial karakteristik agregat halus yang memenuhi persyaratan untuk campuran marshall latasir B. pengganti parsial agregat halus dengan bottom ash batubara dibuat dengan variasi 5 % , 10 % , 15 % , 20 % , 25 % , 30 % , dan 35 % dari total proporsi agregat halus . Hasil penelitian mencatat bahwa penggunaan bottom ash batubara umumnya meningkatkan kualitas campuran latasir B. Latasir campuran B yang memiliki karakteristik marshal terbaik adalah berdasarkan kadar abu batubara dari 17,2 % .Kata kunci : campuran aspal B latasir , bawah batubara abu , karakteristik marshall .

Optimum Partial Replacement of Cement by Nanosilica, Microsilica and Rice Husk Ash for Mass Production of Concrete

2017 ◽  
Vol 751 ◽  
pp. 544-549
Author(s):  
Winai Ouypornprasert ◽  
Narong Traitruengtatsana ◽  
Kong Kamollertvara
Keyword(s):  
Rice Husk ◽  
Rice Husk Ash ◽  
Activity Index ◽  
Silica Content ◽  
Partial Replacement ◽  
Mass Concrete ◽  
Mean Values ◽  
Nonnormal Distributions ◽  
Concrete Production ◽  
High Silica

The objective of this technical paper was to propose the use of optimum partial replacement of cement by pozzolan of high-silica content i.e. nanosilica, silica fume and rice husk ash. Firstly cement hydration, pozzolanic reactions of pozzolan and stoichiometry were reviewed. Then the optimum fractional replacement of cement by pozzolan based on the complete consumption of calcium hydroxide and the strength activity index (SAI) were formulated and proposed. After that the results of a series of tests of cement mortars were shown to verify the proposed concepts. The applicability for the mass concrete production was demonstrated by prediction of mean values of nonnormal distributions from the corresponding specifications.

scholarly journals Effects of Coal Bottom Ash as Cementitious Material on Compressive Strength and Chloride Permeability of Concrete

2020 ◽  
Vol 11 (2) ◽  
Author(s):  
Mohd Haziman Wan Ibrahim ◽  
◽  
Sajjad Ali Mangi ◽  
Mohd Irwan Juki ◽  
◽  
...  
Keyword(s):  
Compressive Strength ◽  
Power Plants ◽  
Environmental Concern ◽  
Bottom Ash ◽  
Cementitious Material ◽  
Partial Replacement ◽  
Chloride Permeability ◽  
Coal Bottom Ash ◽  
Concrete Production ◽  
Lower Chloride

Coal Bottom Ash (CBA) is the waste material produced by coal-based power plants, particularly in Malaysia around 1.7 million tons of CBA was produced annually, which is major environmental concern. Therefore, the use of CBA as a partial replacement of cement in concrete is a possible solution for that pollution; this approach also creates a new corridor in the field of concrete production. However, this study aims to evaluate the effects of CBA as cementitious material on the concrete properties. This study incorporated 10% CBA as a cement replacement by weight method in concrete. However, concrete samples were prepared with and without CBA and immersed in water for 7, 28, 56 and 90 days. Next, the performances of concrete with and without CBA were evaluated in terms of workability, compressive strength, and rapid chloride permeability test. It was found that due to presence of CBA in concrete, workability reduces; no substantial growth in compressive strength at the early ages but substantial rise in strength was noticed after 56 days. Almost 4.7% higher strength was recorded than the control specimens at 90 days. Besides that, concrete containing CBA has lower chloride penetration as compared to the control specimen, which shows its better durability performance. It can be concluded that CBA has an enormous potential to be utilized as a cementitious material in durable concrete production.

scholarly journals Bottom Ash of the Largest Kuzbass Coal Power Plants: Secondary Use Possibility

2021 ◽  
Vol 315 ◽  
pp. 02012
Author(s):  
Aleksey Kargin ◽  
Nikolay Mashkin
Keyword(s):  
Power Plant ◽  
Power Plants ◽  
Building Materials ◽  
Activity Index ◽  
Bottom Ash ◽  
Raw Material ◽  
Coal Power Plant ◽  
Secondary Use ◽  
Coal Power Plants ◽  
Coal Power

Kemerovo district coal power plant, Tom-Usinskaya district coal power plant and Belovo district coal power plant are the largest coal power plants in Kuzbass and during the combustion of coal they generate annually about 1600 tons of coal ash which consists of fly ash and bottom ash. Almost all the generated ash is disposed into ash dumps except a small quantity of fly ash (3.5%) that is effectively utilized. Therefore, secondary use of the bottom ash can be a sustainable solution for reducing its by-products and overcoming the scarcity of raw materials required for construction work. Therefore, the main aim of this research was to determine the chemical composition and granulometric properties of bottom ash to find out the possibility of using it as raw material for the building materials production. A series of laboratory experiments were conducted to determine basicity index, activity index, average grain density, bulk density, true density and grain size distribution. The experimental results reveal that the particle size of ash is predominantly sand-sized while containing some silt-sized and rubble-sized fractions as well. The studied bottom ash has a low basicity and activity index, respectively, does not have independent hydraulic activity. Thus, bottom ash of the largest Kuzbass coal power plants can be used as raw material for the building materials production.

scholarly journals Fabrics, geothermometry, and geochronology of the Songshugou ophiolite: Insights into the tectonic evolution of the Shangdan suture, Qinling orogen, China

Lithosphere ◽  
2019 ◽  
Vol 11 (6) ◽  
pp. 784-803
Author(s):  
Shengsi Sun ◽  
Yunpeng Dong ◽  
Xiaoming Liu ◽  
Dengfeng He ◽  
Chao Cheng
Keyword(s):  
Tectonic Evolution ◽  
Electron Backscatter Diffraction ◽  
High Water ◽  
Coarse Grained ◽  
Spreading Center ◽  
Heavy Rare Earth Element ◽  
Fine Grained ◽  
Suprasubduction Zone ◽  
Backscatter Diffraction ◽  
Water Contents

Abstract The Songshugou ophiolite, located in the northern Qinling belt, consists mainly of metamorphosed mafic and ultramafic rocks recording details of deformation and metamorphism that occurred during subduction, accretion, and collision along the Shangdan suture in the Qinling orogenic belt. Electron backscatter diffraction measurements revealed that the harzburgites are dominated by olivine C-type crystal preferred orientations (CPOs), which were possibly induced by high pressure during slab subduction. Olivine A-type CPOs were also observed in some harzburgites, representing the remnants of the original fabric in oceanic mantle rocks formed in the spreading center of the Shangdan ocean. Coarse-grained dunites are characterized by B-type CPOs, which may have been caused by melt-rock reactions and/or high water contents in a suprasubduction-zone setting during exhumation. Fine-grained dunites are also dominated by B-type CPOs, suggesting that grain-size reduction related to mylonitization did not result in fabric variations. Combined with the mineral assemblages, application of geothermometry suggested that the Songshugou ophiolite has experienced metamorphism and deformation under amphibolite-facies conditions. Zircons from garnet-bearing amphibole schist are characterized by flat heavy rare earth element (HREE) patterns and low Th/U ratios and yielded a mass spectrometry U-Pb age of 500.5 ± 8.8 Ma, representing the peak metamorphic age of the metamafic rocks. Other zircons displayed relative HREE enrichment and a clearly negative Eu anomaly and gave an age of 492.5 ± 3.0 Ma, constraining the time of the exhumation of the ophiolite. Integrated with all the available regional geology, our new fabric, geochemical, and geochronological data suggest that the tectonic evolution of the Songshugou ophiolite can be proximately constrained as subduction at ca. 500 Ma and exhumation at ca. 492 Ma.

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