Kliknij ten link, aby zobaczyć inne rodzaje publikacji na ten temat: Fly ash concrete.
Artykuły w czasopismach na temat „Fly ash concrete”
Utwórz poprawne odniesienie w stylach APA, MLA, Chicago, Harvard i wielu innych
Sprawdź 50 najlepszych artykułów w czasopismach naukowych na temat „Fly ash concrete”.
Przycisk „Dodaj do bibliografii” jest dostępny obok każdej pracy w bibliografii. Użyj go – a my automatycznie utworzymy odniesienie bibliograficzne do wybranej pracy w stylu cytowania, którego potrzebujesz: APA, MLA, Harvard, Chicago, Vancouver itp.
Możesz również pobrać pełny tekst publikacji naukowej w formacie „.pdf” i przeczytać adnotację do pracy online, jeśli odpowiednie parametry są dostępne w metadanych.
Przeglądaj artykuły w czasopismach z różnych dziedzin i twórz odpowiednie bibliografie.
1
Dr. R.R Singh, Dr R. R. Singh, i Er Arpan Jot Singh Sidhu. "High Volume Fly Ash Concrete". International Journal of Scientific Research 3, nr 6 (1.06.2012): 142–45. http://dx.doi.org/10.15373/22778179/june2014/50.
Pełny tekst źródła
2
Chen, Bo, Yue Bo Cai, Jian Tong Ding i Yao Jian. "Crack Resistance Evaluating of HSC Based on Thermal Stress Testing". Advanced Materials Research 168-170 (grudzień 2010): 716–20. http://dx.doi.org/10.4028/www.scientific.net/amr.168-170.716.
Pełny tekst źródłaStreszczenie:
In order to evaluate the crack resistance of high strength fly ash concrete, concretes with different contents of silica fume and fly ash were compared with same strength grade by adjusting water to binder ratio. Compared with the concrete with 5% silica fume plus 35% fly ash，concrete with 40% fly ash has same mechanical properties and tensile strain as well as lower drying shrinkage. Complex crack resistance of high strength fly ash concretes were evaluated by Temperature Stress Testing Machine (TSTM). The results show that fly ash concretes have outstanding crack resistance because of higher allowable temperature differential and lower cracking temperature.
3
Liu, Hanbing, Guobao Luo, Longhui Wang i Yafeng Gong. "Strength Time–Varying and Freeze–Thaw Durability of Sustainable Pervious Concrete Pavement Material Containing Waste Fly Ash". Sustainability 11, nr 1 (31.12.2018): 176. http://dx.doi.org/10.3390/su11010176.
Pełny tekst źródłaStreszczenie:
Pervious concretes, as sustainable pavement materials, have great advantages in addressing a number of environmental issues. Fly ash, as the industrial by-product waste, is the most commonly used as cement substitute in concrete. The objective of this paper is to study the effects of waste fly ash on properties of pervious concrete. Fly ash was used to replace cement with equivalent volume method at different levels (3%, 6%, 9%, and 12%). The control pervious concrete and fly ash modified pervious concrete were prepared in the laboratory. The porosity, permeability, compressive strength, flexural strength, and freeze–thaw resistance of all mixtures were tested. The results indicated that the addition of fly ash decreased the early-age (28 d) compressive strength and flexural strength, but the long-term (150 d) compressive strength and flexural strength of fly ash modified pervious concrete were higher than that of the early-age. The adverse effect of fly ash on freeze–thaw resistance of pervious concrete was observed when the fly ash was added. The porosity and permeability of all pervious concrete mixtures changed little with the content of fly ash due to the use of equal volume replacement method. Although fly ash is not positive to the properties of pervious concrete, it is still feasible to apply fly ash as a substitute for cement in pervious concrete.
4
Mao, Ming Jie, Qiu Ning Yang, Wen Bo Zhang i Isamu Yoshitake. "Fly-Ash Concretes of 50% of the Replacement Ratio to Reduce the Cracking in Concrete Structures". Applied Mechanics and Materials 405-408 (wrzesień 2013): 2665–70. http://dx.doi.org/10.4028/www.scientific.net/amm.405-408.2665.
Pełny tekst źródłaStreszczenie:
Fly-ash concrete used in massive concrete structure has superior advantages to reduce hydration heat. On the other hand, the fly-ash concrete has negative property of low strength development at early age because pozzolanic reaction of fly-ash activates at mature age, such as after 28 days. To investigate these characteristics of fly-ash used in concrete, the present study discusses thermal cracking possibility of fly-ash concrete by using FE analysis software. The present study employs prediction formulae proposed by Zhang and Japanese design code in the simulations. The objects in this study are normal strength concrete mixed of fly-ash up to 50% of replacement ratio to cement. The comparative investigations show that temperature effect is more significant than strength development at early age. Based on the analytical study, high volume fly-ash concretes of 30-50% of the replacement ratio can be concluded as effective and useful materials to reduce the cracking possibility in massive concrete structures. Keywords-Fly-ash concrete; Early Age, Prediction Formulae for Strength; Thermal Stress Analysis
5
Sinthaworn, Suppachai. "Water Penetration Resistance of Fly Ash Concrete Incorporating with Quarry Wastes". Materials Science Forum 886 (marzec 2017): 159–63. http://dx.doi.org/10.4028/www.scientific.net/msf.886.159.
Pełny tekst źródłaStreszczenie:
Slump of fresh concrete, compressive strength and water penetration depth under pressure of fly ash concrete incorporate with quarry waste as fine aggregate were investigated. The cementitious materials of the concrete includes ordinary Portland cement 80% and fly ash 20% by weight of cementitious. The mix proportions of the concrete were set into two classes of compressive strength. The results show that fly ash enhances workability of both concretes (normal concrete and concrete incorporate with quarry waste). Increasing the percentage of quarry dusts as fine aggregate in concrete seem negligible effect on the compressive strength whereas adding fly ash shows a slightly improve the compressive strength in the case of cohesive concrete mixture. Besides, adding the suitable amount of fly ash could improve the permeability of concrete. Therefore, fly ash could be a good admixture to improve the water resistant of normal strength concrete and also could be a supplemental material to improve the compressive strength of normal high strength concrete.
6
Chen, How-Ji, Neng-Hao Shih, Chung-Hao Wu i Shu-Ken Lin. "Effects of the Loss on Ignition of Fly Ash on the Properties of High-Volume Fly Ash Concrete". Sustainability 11, nr 9 (13.05.2019): 2704. http://dx.doi.org/10.3390/su11092704.
Pełny tekst źródłaStreszczenie:
This study presents the experimental results of fresh and hardened properties of concrete incorporating high-volume fly ash (HVFA). Two kinds of low-calcium fly ash with loss on ignition (LOI) of 5% and 8% were used as replacement for cement and/or fine aggregate of 0% (control), 20%, 40%, 50%, 60% and 80% by weight of the total cementitious materials. The properties of fresh concrete tested included the slump, air content, unit weight and setting time; those of hardened concrete determined included compressive strength, modulus of elasticity, flexural strength and drying shrinkage. Test results indicate that the concretes made with high-LOI (8%) fly ash can be successfully produced for structural concrete, which contains fly ash of up to 60% of the total cementitious materials. The high-LOI fly ash-concretes with higher replacement levels presented longer setting times. However, although both the fresh and hardened properties of high LOI fly ash concretes were inferior to those of the low-LOI (5%) fly ash concretes, the high modulus of elasticity, the adequate strength development characteristics both at early and later ages (up to 365 days) and the low dry shrinkage were observed when compared to those of the control concrete with a comparable 28-day compressive strength of 30 MPa.
7
Banchong, Nilankham, Warangkana Saengsoy i Somnuk Tangtermsirikul. "STUDY ON MECHANICAL AND DURABILITY PROPERTIES OF MIXTURES WITH FLY ASH FROM HONGSA POWER PLANT". ASEAN Engineering Journal 10, nr 1 (1.01.2020): 9–24. http://dx.doi.org/10.11113/aej.v10.15535.
Pełny tekst źródłaStreszczenie:
The use of fly ash in concrete improves several characteristics of conventional cement-based pastes, mortars, and concrete such as reduces heat of hydration, increases strength in long-term and enhances durability. However, types and volume of fly ash affect behavior of resulting pastes, mortars and concrete. In this study, the characteristics of pastes, mortars, and concrete with 20% and 30% binder replacement with a Hongsa fly ash from Laos (FAH3) and two fly ashes from Thailand (FAM and FAB) were studied. Further, mechanical and durability properties of Hongsa fly ash mortars and concrete are investigated through specific gravity, Blaine fineness, normal consistency, setting times, water requirement, strength index, slump and slump retention, compressive strength of concrete with a fixed slump, compressive strength of concrete with a fixed w/b of 0.5, semi-adiabatic temperature, total shrinkage, carbonation depth, H2SO4 acid resistance, rapid chloride penetration (RCP) and chloride distribution. The experimental results show that the Hongsa fly ash contains large amount of non-spherical particles with coarse cavities, leading to high surface area and high Blaine fineness value. Accordingly, Hongsa fly ash was found to have high water requirement. In comparison to the ordinary Portland cement type I (OPC) and Mae Moh fly ash (FAM), the Hongsa fly ash was found to generate lower heat. As a result, the Hongsa fly ash shows its potential in the application of mass concrete. Similarly, the Hongsa fly ash mortar exhibited the lowest carbonation depth when compared to the FAM and FAB mortars. In term of RCPT and chloride distribution test, the Hongsa fly ash concrete shows the lowest Cl⁻ penetrability when compared with Portland cement type I (OPC) concrete, FAM and FAB concretes. Based on the experimental results, the Hongsa fly ash was found to be applicable in concrete works.
8
Li, Shuang Xi, Tuan She Yang, Zhi Ming Wang i Quan Hu. "Experiment and Micro-Mechanism Study on Mechanical Properties and Durability of High-Calcium Fly Ash Concrete". Key Engineering Materials 480-481 (czerwiec 2011): 59–65. http://dx.doi.org/10.4028/www.scientific.net/kem.480-481.59.
Pełny tekst źródłaStreszczenie:
Low-calcium fly ash is paid much attention for its wide use in engineering, the research and application technology of it are very mature, but as to high-calcium fly ash concrete, the researches on stability, mechanical property and durability of it are very less , The existing researches are still inadequate for practice of engineering. As to this problem, using small shek kip hydropower project as example, the volume stability of high-calcium fly ash concretes with different fly ash dosages are tested, then the optimal dosage of the high-calcium fly ash is determined; based on this, the impacts of high-calcium fly ash on the performance of mechanical properties , impermeability and frost resistance of concrete are studied; Finally, macro performance is analyzed from a micro-mechanism point of view through taking the electron micrograph. As the study shows, the optimal dosage of high-calcium fly ash should be taken as 20% -25%; for the concrete with special requirements, the dosage can be relaxed to 30% when the high-calcium fly ash achieves high quality. The compressive strength of high-calcium fly ash concrete is higher than the low-calcium fly ash concrete. Strength development advantage of high-calcium fly ash concrete reflects at the early age, this advantage takes the trend of weakening as the development of age. Concrete mixed with high-calcium fly ash has good performance in impermeability. The high-calcium fly ash has high activity, the high-calcium fly ash and secondary hydration reaction products can be filled into the pore capillary and cracks of the concrete structure, improving the pore structure, thereby increasing the density of cement paste. High-calcium fly ash concrete has good performance in frost resistance. The destructive effects of freeze-thaw cycles on cement structure has connection with the microstructure of cement and impermeability , the improvement of impermeability avoids the water entering into the concrete, reduces the risk of destruction caused by frost heave.The study on micro-mechanism proves well the macro-phenomena above.
9
Sounthararajan, Vallarasu Manoharan. "Empirical Prediction Models for Strength Gain Properties of Fly Ash Based Concrete Subjected to Accelerated Curing". Advanced Materials Research 1150 (listopad 2018): 73–90. http://dx.doi.org/10.4028/www.scientific.net/amr.1150.73.
Pełny tekst źródłaStreszczenie:
Experimental investigations on the early age, strength gain properties of fly ash blended cement concretes containing low and high volume fly ash replacement were studied. Concrete mixes were prepared with two different fly ash contents and varying concrete ingredients with water to binder ratio (w/b), fine to coarse aggregate ratio (F/c) and accelerator dosage. Five different curing techniques, namely controlled humidity curing; hot air oven curing, steam curing, hot water curing and normal water curing were adopted for curing the fly ash based concretes. Test results showed evidence the influence of accelerating admixtures and accelerated curing for obtaining the high early strength properties in fly ash mixed concrete. Most notably a maximum 1 day compressive strength of 40.20 MPa and 34.60 MPa with low (25%) and high (50%) volume fly ash concretes were obtained respectively in this study. Experimental results clearly indicated that the improvements on the strength gain properties with the careful selection of mix ingredients; accelerator addition and accelerated curing in fly ash based concrete mixes. Also, significant improvements on the flexural strength, elastic modulus, dynamic modulus and the ultrasonic pulse velocity test were noticed.
10
Powar, Namrata Shankar. "Corrosion of Reinforcement in HVFA Concrete". International Journal for Research in Applied Science and Engineering Technology 10, nr 10 (31.10.2022): 1356–70. http://dx.doi.org/10.22214/ijraset.2022.47174.
Pełny tekst źródłaStreszczenie:
bstract: Concrete is a composite material composed of fine aggregate and coarse aggregate bonded together with cement that hardens over time. Concrete is one of the most frequently used building materials. Water cement ratio plays an important role which influences various properties such as workability, strength and durability. In concrete cement is main concrete material.The use of fly ash as an addictive material, as replacement of cement. The most important benefit is reduced permeability to water and chemicals. Properly cured concrete made with fly ash creates a denser product because the size of pores is reduced. This increases strength and reduces permeability and corrosion. For concrete mixes 43 grade of ordinary Portland cement and class F type Fly ash is concrete cubes are casted with varying percentage of fly ash and ultrafine fly ash. Three types of percentage is used as replacement of cement with fly ash. For replacement 40% ,50% and 60% fly ash is used. The size of cubes is 150mm x 150mm x150mm.Water/cement ratio 0.36 and Four types of percentage of Ultra fine fly ash is added such as 6%,8%,10% and 12%. Test is carried out after 7 days and 28 days of curing period. The tests conducted on concrete specimens are compressive strength. Results show that the addition of 6 wt.% UFFA significantly improved the early age and later age compressive strengths of HVFA concretes. The HVFA concrete containing 50% fly ash and 6% UFFA exhibited higher corrosion resistance properties. The results also indicate the effectiveness of UFFA in producing high packing density and in accelerating the pozzolanic activity to produce more C–S–H gel by consuming calcium hydroxide (CH) in HVFA concretes.
11
Turuallo, Gidion, i Harun Mallisa. "Sustainable cementitious materials: The effect of fly ash percentage as a part replacement of portland cement composite (PCC) and curing temperature on the early age strength of fly ash concrete". MATEC Web of Conferences 258 (2019): 01001. http://dx.doi.org/10.1051/matecconf/201925801001.
Pełny tekst źródłaStreszczenie:
This research aims to determine the effect of fly ash percentage as a part replacement of Portland cement and curing temperatures to the early age strength of concrete. The percentages of fly ash used were 0, 10 and 15% by cement weight. The cured temperatures were 25, 30 dan 50°C. The concrete specimens were cubes of 150 x 150 x 150 mm3. The cubes, which were cured at 25°C, placed in water tank, while those cured at 30 and 50°C cured in oven until 7 days and then continued in water. The testing was conducted at ages 3, 7, 14 dan 28 days. The results showed that at early ages, the strength of concrete without fly ash cured at 25°C were higher than that of fly ash concrete. The higher level replacement of cement with fly ash, the lower strength of concrete obtained. The higher the curing temperature at earlier age resulted the higher the strength of concrete. The strength of concretes with 10% of fly ash cured at 25, 30 and 50°C at age three days were 15.111, 15.481 and 16.296 MPa respectively. Conversely, the strength of concrete that of cured at higher temperatures at ages 28 days, were lower than that of concretes cured at lower temperature. The results of this research also showed that fly ash could improve the workability of concrete.
12
Tan, Kiang Hwee, i Hongjian Du. "Towards a sustainable concrete: “sandless” concrete". Science and Engineering of Composite Materials 18, nr 1-2 (1.06.2011): 99–107. http://dx.doi.org/10.1515/secm.2011.013.
Pełny tekst źródłaStreszczenie:
AbstractAs a step towards ensuring the sustainability of concrete as a construction material, an investigation was carried out on the mechanical and durability properties of concrete made without natural sand, termed “sandless” concrete, and with cement partially replaced by fly ash. Four groups of concrete mixes, with water-cement (w/c) ratios of 0.40, 0.45, 0.50 and 0.55, respectively, were studied. For each w/c ratio, there were six mixes with 0, 10%, 20%, 30%, 40% and 50% of cement content replaced by fly ash by mass, and one normal concrete mix containing natural sand. The difference in mechanical properties between normal and “sandless” concrete was not significant. “Sandless” concrete mixes with cement replaced by fly ash by <30% showed comparable compressive, splitting tensile and flexural strengths as those without fly ash. However, the elastic modulus was reduced with the incorporation of fly ash. In addition, use of fly ash led to reduced drying shrinkage of “sandless” concrete, and significantly improved the resistance to chloride ion penetration. The resistance to sulfate attack, on the other hand, seemed to decrease with higher fly ash content. From the study, it appears that “sandless” concrete with cement replaced by fly ash up to 30% could be considered for structural applications.
13
Jura, Jakub, i Malgorzata Ulewicz. "Assessment of the Possibility of Using Fly Ash from Biomass Combustion for Concrete". Materials 14, nr 21 (7.11.2021): 6708. http://dx.doi.org/10.3390/ma14216708.
Pełny tekst źródłaStreszczenie:
This article analyses the possibility of using fly ash from the combustion of wood–sunflower biomass in a fluidized bed boiler as an additive to concrete. The research shows that fly ash applied in an amount of 10–30% can be added as a sand substitute for the production of concrete, without reducing quality (compression strength and low-temperature resistance) compared to control concrete. The 28-day compressive strength of concrete with fly ash increases with the amount of ash added (up to 30%), giving a strength 28% higher than the control concrete sample. The addition of fly ash reduces the extent to which the compression strength of concrete is lowered after low-temperature resistance tests by 22–82%. The addition of fly ash in the range of 10–30% causes a slight increase in the water absorption of concrete. Concretes containing the addition of fly ash from biomass combustion do not have a negative environmental impact with respect to the leaching of heavy metal ions into the environment.
14
Kosior-Kazberuk, M., i D. Józwiak-Niedzwiedzka. "Influence of Fly Ash From Co-Combustion of Coal and Biomass on Scaling Resistance of Concrete / Wpływ Popiołu Lotnego Ze Współspalania Wegla I Biomasy Na Odpornosc Betonu Na Powierzchniowe Łuszczenie". Archives of Civil Engineering 56, nr 3 (1.09.2010): 239–54. http://dx.doi.org/10.2478/v.10169-010-0013-x.
Pełny tekst źródłaStreszczenie:
Abstract Industrial utilization of fly ash from various kinds of fuel plays an important role in the environmentally clean and cost effective power production. The primary market for fly ash utilization is as a pozzolanic addition in concrete production. The paper concerns the concretes containing fly ash called Fly Ash from Biomass (FAB) from co-combustion of hard coal and wood biomass (wood chips). Characterization of the fly ash was carried on by means of X-ray diffractometry and E-SEM/EDS analysis. The results of laboratory studies undertaken to evaluate the influence of FAB on concrete resistance to surface scaling due to cyclic freezing and thawing in the presence of NaCl solution were presented. The tests were carried out for concretes containing up to 25% of fly ash related to cement mass. Additionally, the microstructure of air-voids was described. It was concluded that the FAB has significant effect on concrete freeze/thaw durability. The replacement of cement by fly ash from co-combustion progressively transformed the concrete microstructure into less resistant against freeze/thaw cycles and excessive dosage (over 15%) may dangerously increase the scaling.
15
Rantung, Dilan, Steve W. M. Supit i Seska Nicolaas. "Effects of different size of fly ash as cement replacement on self-compacting concrete properties". Journal of Sustainable Engineering: Proceedings Series 1, nr 2 (30.09.2019): 180–86. http://dx.doi.org/10.35793/joseps.v1i2.25.
Pełny tekst źródłaStreszczenie:
This paper aims to investigate experimentally the influence of replacing cement with different fineness of fly ash based on flowability, passing ability, compressive strength, tensile strength (splitting). Concretes with 15% fly ash (passed a number 100 sieve) and fine fly ash (passed a number 200 sieve) as cement replacement were cast and tested at 7, 14, 28 days after water curing. A superplasticizer in the form of viscocrete 3115 N was constantly used for each concrete mixtures as much as 1% by weight of cement. The results show that the use of fly ash does not significantly increased the compressive strength and tensile strength of SCC mixtures. However, concrete with 15% fine fly ash its self and combined 7.5% fly ash with 7.5% fine fly ash show better flowability and passing ability when compared to concrete with cement only indicating the performance of using smaller particle sizes of fly ash could lead better properties of SCC that can be potentially used for building construction application.
16
Wang, Lei, Shihua Zhou, Yan Shi, Yajun Huang, Feng Zhao, Tingting Huo i Shengwen Tang. "The Influence of Fly Ash Dosages on the Permeability, Pore Structure and Fractal Features of Face Slab Concrete". Fractal and Fractional 6, nr 9 (28.08.2022): 476. http://dx.doi.org/10.3390/fractalfract6090476.
Pełny tekst źródłaStreszczenie:
Concrete-face slabs are the primary anti-permeability structures of the concrete-face rockfill dam (CFRD), and the resistance of face slab concrete to permeability is the key factor affecting the operation and safety of CFRDs. Herein, the influences of five fly ash dosages (namely 10%, 20%, 30%, 40% and 50%) on the permeability property of face slab concretes were investigated. Moreover, the difference in the permeability caused by the fly ash dosage variations is revealed in terms of the pore structure and fractal theory. The results illustrate that: (1) The inclusion of 10–50% fly ash lowered the compressive strength of face slab concretes before 28 days of hydration, whereas it contributed to the 180-day strength increment. (2) The incorporation of 10–50% fly ash raised the average water-seepage height (Dm) and the relative permeability coefficient (Kr) of the face slab concrete by about 14–81% and 30–226% at 28 days, respectively. At 180 days, the addition of fly ash improved the 180-day impermeability by less than 30%. (3) The permeability of face slab concretes is closely correlated with their pore structures and Ds. (4) The optimal fly ash dosage in terms of the long-term impermeability and pore refinement of face slab concretes is around 30%. Nevertheless, face slab concretes containing a high dosage of fly ash must be cured for a relatively long period before they can withstand high water pressure.
17
Yao, Lei, Hong Zhen Kang i Kai Wu Jia. "Experimental Study on Mixing Ratio of Concrete Adding Fly Ash and Slag Powder". Applied Mechanics and Materials 148-149 (grudzień 2011): 1025–28. http://dx.doi.org/10.4028/www.scientific.net/amm.148-149.1025.
Pełny tekst źródłaStreszczenie:
13 Groups of C20 concrete specimens and 11 groups of C60 concrete specimens adding different content of fly ash and slag powder, comparing with normal concrete specimens, were tested to analyze compressive strength and workability. The test results show: When adding fly ash only, equivalent replacing volume should not exceed 30%, and for lower strength concretes (such as C20) the adding volume should be lower than 30%, otherwise, the compressive strength was influenced greatly. When adding slag powder only, the replacing volume should increase to 40%, meanwhile the workability must be supervised. When adding fly ash and slag powder simultaneously, the adding volume should reach to 50%, and the ratio of fly ash to slag should be controlled. For C20 concrete the ratio of fly ash to slag powder should not exceed 10% and for C60 concrete the ratio should reach to 25%.
18
Liu, Ming Hui, i Yuan Feng Wang. "Prediction of the Strength Development of Fly Ash Concrete". Advanced Materials Research 150-151 (październik 2010): 1026–33. http://dx.doi.org/10.4028/www.scientific.net/amr.150-151.1026.
Pełny tekst źródłaStreszczenie:
The effect of fly ash in improving the mechanical properties of concrete is investigated and the existing concrete strength development models are studied. Based on the chemic reactivity properties between fly ash and cement, an appropriate concrete strength model are chosen, and a new model for the fly ash strength factor combing Maturity method is built up and the factors are regressed by existing experimental datum. A total of 24 concretes, including two concretes were produced with two partial fly ash replacement ratios (23.7%, 32.7%). The cubic samples produced from ash fly concrete were demoulded after a day, and cured at standard temperature ( in GB/T 50081-2002) with 100% relative humidity until 28 days, then cured in water. The compressive strength tests were carried out on the cubic specimens at different ages. The compressive strength with time was evaluated by using the new predicted model. It was found that the calculated results by new method are fit the experimental data well.
19
R, Ramasubramani. "Mechanical and Characterization Behavior of Light Weight Aggregate Concrete Using Sintered Fly Ash Aggregates and Synthetic Fibers". ECS Transactions 107, nr 1 (24.04.2022): 1737–49. http://dx.doi.org/10.1149/10701.1737ecst.
Pełny tekst źródłaStreszczenie:
This study focuses into the usage of sintered fly ash aggregate in the production of lightweight concrete. To minimize the environmental impacts would alleviate the waste disposal issues related with fly ash and contribute in the decrease of environmental pollution. Construction materials are in high need in the domestic sector, which is growing increasingly rare day by day. In India, the power sector is currently reliant on thermal power plants, which generate a massive amount of fly ash, estimated to be roughly 200 million tons each year. Fly ash is a waste product produced by thermal power stations when pulverized coal is burned. The use of industrial waste as a building material is a significant step towards long-term sustainability. The mechanical characteristics of sintered fly ash aggregates were discussed. According to the results, the specific gravity of these aggregates is 16–46% lower than that of regular weight aggregates, and they have higher water absorption. The 28-day comp strengths of sintered fly ash aggregate concretes range from 27 to 74MPa, with densities ranging from 1651 to 2017 kg/m3. According to the study, sintered fly ash aggregate concrete is also one of the materials that might be used to develop structural concrete. Sintered fly ash aggregate was used to replace natural aggregate (12%). The compressive, tensile, and flexural strengths of concrete produced with natural aggregate and sintered fly ash aggregate were compared. Also, concretes were conducted to a microstructure test and a SEM analysis.
20
Szcześniak, Anna, Jacek Zychowicz i Adam Stolarski. "Assessment of the influence of fly ash additive on the tightness of concrete with furnace cement CEM IIIA 32,5N". Bulletin of the Military University of Technology 66, nr 4 (31.12.2017): 153–64. http://dx.doi.org/10.5604/01.3001.0010.8228.
Pełny tekst źródłaStreszczenie:
The analysis of influence of fly ash additive to concrete on the basis of cement CEM IIIA 32,5 N on the tightness and strength was presented in the paper. Researches were carried out for three types of concrete made with the use of CEM IIIA 32,5N LH HSR NA cement. The basic recipe of concrete does not contain the additive of fly ash, while two other concretes contain the fly ash additive in an amount of 25% and 33% of the cement mass. Laboratory investigations of the concrete samples were carried out under conditions of long-term maturation in the range of the water tightness and the depth of water penetration in concrete, compressive strength and tensile strength of concrete at splitting. Keywords: concrete testing, furnace cement, fly ash additive, water tightness of concrete, strength of concrete.
21
Przychodzień, Patrycja, i Jacek Katzer. "Properties of Structural Lightweight Aggregate Concrete Based on Sintered Fly Ash and Modified with Exfoliated Vermiculite". Materials 14, nr 20 (9.10.2021): 5922. http://dx.doi.org/10.3390/ma14205922.
Pełny tekst źródłaStreszczenie:
Despite the undoubted advantages of using lightweight concrete, its actual use for structural elements is still relatively small in comparison to ordinary concrete. One of the reasons is the wide range of densities and properties of lightweight aggregates available on the market. As a part of the research, properties of concrete based on sintered fly ash were determined. The ash, due to its relatively high density is suitable to be used as a filler for structural concretes. Concrete was based on a mixture of sintered fly ash and exfoliated vermiculite aggregate also tested. The purpose of the research was to determine the possibility of using sintered fly ash as alternative aggregate in structural concrete and the impact of sintered fly ash lightweight aggregate on its physical, mechanical and durability properties. Conducted tests were executed according to European and Polish standards. Created concretes were characterized by compressive strength and tensile strength ranging from 20.3 MPa to 54.2 MPa and from 2.4 MPa to 3.8 MPa, respectively. The lightest of created concretes reached the apparent density of 1378 kg/m3.
22
Wang, Lei, Yajun Huang, Feng Zhao, Tingting Huo, E. Chen i Shengwen Tang. "Comparison between the Influence of Finely Ground Phosphorous Slag and Fly Ash on Frost Resistance, Pore Structures and Fractal Features of Hydraulic Concrete". Fractal and Fractional 6, nr 10 (15.10.2022): 598. http://dx.doi.org/10.3390/fractalfract6100598.
Pełny tekst źródłaStreszczenie:
Hydraulic concrete in cold regions is necessary for good frost resistance. The utilization of finely ground PS (FGPS) in the construction of hydropower projects could solve the pollution issue and the fly ash shortage problem. In this work, the influence of FGPS and fly ash on frost resistance, pore structure and fractal features of hydraulic concretes was investigated and compared. The main results are: (1) The inclusion of 15–45% FGPS reduced the compressive strength of plain cement concretes by about 21–52%, 7–23% and 0.4–8.2% at 3, 28 and 180 days, respectively. (2) The inclusion of FGPS less than 30% contributed to the enhancement of 180-day frost resistance. At the same dosage level, the FGPS concrete presented larger compressive strengths and better frost resistance than fly ash concrete at 28 and 180 days. (3) At 3 days, both the addition of FGPS and fly ash coarsened the pore structures. FGPS has a much stronger pore refinement effect than fly ash at 28 and 180 days. The correlation between frost resistance of hydraulic concrete and pore structure is weak. (4) At 28 days, the incorporation of FGPS and fly ash weakened the air void structure of hydraulic concrete. At 180 days, the presence of FGPS and fly ash was beneficial for refining the air void structure. The optimal dosage for FGPS and fly ash in terms of 180-day air void refinement was 30% and 15%, respectively. The frost resistance of hydraulic concretes is closely correlated with the air void structure. (5) The pore surface fractal dimension (Ds) could characterize and evaluate the pore structure of hydraulic concretes, but it was poorly correlated with the frost resistance.
23
Huang, Xiaoliang, Yong Zhang, Dingge Hou, Cheng Xue, Guang Li, Bo Li, Zhendi Wang i Bin Li. "Mix-ratio optimization for air-tight tunnel concrete". E3S Web of Conferences 358 (2022): 02042. http://dx.doi.org/10.1051/e3sconf/202235802042.
Pełny tekst źródłaStreszczenie:
In this paper, we studied the effect of fly ash and mix ratio on the compressive strength of air-tight concrete, the introduced fly ash would decrease the early compressive strength of concrete. With curing age increasing, the gape in the compressive strength between concrete without fly ash and concrete containing fly ash is decreasing. Moreover, concrete containing fly ash showed smaller air permeability, the introduced fly ash improved the airtightness of concrete.
24
Huang, Shuang Jie, Zeng Chao Ge, Ling Zhou i Jun Long Zhou. "Effect of Fly Ash on Expansion Properties of Concrete Added with Expansive Agents". Advanced Materials Research 393-395 (listopad 2011): 684–87. http://dx.doi.org/10.4028/www.scientific.net/amr.393-395.684.
Pełny tekst źródłaStreszczenie:
This paper studies the effect of fly ash on expansion properties of mortar and concrete with the addition of expansive agents. It concludes that fly ash have different influence on the expansive effect of concrete with addition of expansive agents, the original fly ash hardly has any effect on the expansion properties of mortar and concrete with the addition of expansive agents. But, the milled fly ash has great effect on expansion properties of mortar and concrete with the addition of expansive agents, and the more the milled fly ash is added, the greater the effect is. Even if content of the original fly ash is over 30 percent, the value of expansive rate of mortar and concrete with addition of the original fly ash is as high as that of mortar and concrete without addition of fly ash. When the content of milled fly ash is over 10 percent, the effect on the expansion properties is weakened. When fly ash and expansive agent added to concrete at the same time, fly ash the original fly ash must be used.
25
Szcześniak, Anna, Jacek Zychowicz i Adam Stolarski. "Influence of Fly Ash Additive on the Properties of Concrete with Slag Cement". Materials 13, nr 15 (23.07.2020): 3265. http://dx.doi.org/10.3390/ma13153265.
Pełny tekst źródłaStreszczenie:
This paper presents research on the impact of fly ash addition on selected physical and mechanical parameters of concrete made with slag cement. Experimental tests were carried out to measure the migration of chloride ions in concrete, the tightness of concrete exposed to water under pressure, and the compressive strength and tensile strength of concrete during splitting. Six series of concrete mixes made with CEM IIIA 42.5 and 32.5 cement were tested. The base concrete mix was modified by adding fly ash as a partial cement substitute in the amounts of 25% and 33%. A comparative analysis of the obtained results indicates a significant improvement in tightness, especially in concrete based on CEM IIIA 32.5 cement and resistance to chloride ion penetration for the concretes containing fly ash additive. In the concretes containing fly ash additive, a slower rate of initial strength increase and high strength over a long period of maturation are shown. In accordance with the presented research results, it is suggested that changes to the European standardization system be considered, to allow the use of fly ash additive in concrete made with CEM IIIA 42.5 or 32.5 cement classes. Such a solution is not currently acceptable in standards in some European Countries.
26
Sachova, Hana, Petr Huňka, Jiří Kolísko, Stanislav Řeháček i David Čítek. "Concrete with High Content of Fly-Ash for Common Use in the Czech Republic". Advanced Materials Research 1000 (sierpień 2014): 190–95. http://dx.doi.org/10.4028/www.scientific.net/amr.1000.190.
Pełny tekst źródłaStreszczenie:
Concrete with high substitute of the cement with fly-ash (FAC) is favourably used for structures with undesirable development of hydration heat or where reduction of the share of Portland clinker in the adhesive provides better resistance of concrete against impacts of acidic aggressive environment. Due to pozzolanic reaction fly-ash participates on formation of cement or adhesive stone and contributes to increased strength of concrete. As the pozzolanic reaction process is gradual its impact on the increased concrete strength is shown within longer time horizon (i.e. after lapse of standard age) and fly-ash concretes are therefore characterized by a short-term low strength which is one of its disadvantages mostly during winter season. However during summer season concretes with partial substitute of cement with fly-ash are beneficial solution for common use even from the aspect of reduced material costs on concrete production. Reduced cement volume in the concrete is nevertheless limited by requirements of ČSN EN 206-1 on concrete composition which is making difficult launch of concrete with higher cement substitutions with fly-ash on the Czech market. FAC allow effective use of the fly-ash, which is otherwise a waste product representing environmental load on spoil heaps as a substitute of clinker, the production of which is also environmentally loading from the power and raw materials aspect. This environmental input of FAC would be hopefully more considered for design of building structures in the future.
27
Li, Mu. "A Review on Early Age and Long-term Compressive Strength of High-volume Fly Ash Concrete". MATEC Web of Conferences 207 (2018): 01004. http://dx.doi.org/10.1051/matecconf/201820701004.
Pełny tekst źródłaStreszczenie:
Fly ash is a by-product of the combustion of the coal-fired electric power stations, and disposal of fly ash has been one of the environmental challenges. Much of the studies have been focused on the mechanical property of fly ash concrete. It is no doubt that the use of high-volume fly ash as a partial replacement of cement is also one of the effect way to utilize fly ash. It is known that the compressive strength of fly ash concrete is lower than that of ordinary concrete at early age, especially for high-volume fly ash concrete. It is urgent for engineers to consider the compressive strength of high-volume fly ash concrete at different curing age. In this review, the compressive strength of high-volume fly ash concrete in various literature was reported and then analyzed. Furthermore, the proposal of the utilization of high-volume fly ash concrete is provided.
28
Shaker, Muhammad Rauf, Mayurkumar Bhalala, Qayoum Kargar i Byungik Chang. "Evaluation of Alternative Home-Produced Concrete Strength with Economic Analysis". Sustainability 12, nr 17 (20.08.2020): 6746. http://dx.doi.org/10.3390/su12176746.
Pełny tekst źródłaStreszczenie:
Ready-mix concrete is not always affordable because it is less economical for small projects. This study shows an effort to introduce alternative home-produced concrete for small paving areas such as sidewalks, backyards, or fixing the existing concrete and discusses the economic evaluation of the alternative concrete for home purpose. The materials being used in this study are available locally or are easily purchased. The primary objective of the study is to analyze the compressive strength and conduct economic analysis of alternative home-produced concrete with different mix designs. Wood ash, fly ash, and recycled aggregate concretes are the alternative concrete types discussed in this study. Fly ash can replace Portland cement up to 30% without losing significant compressive strength of the concrete. Furthermore, fly ash is less expensive than Portland cement and can reduce the cost of concrete by saving approximately 15%. Wood ash can be used up to 25% in concrete without losing considerable strength which saves approximately 13% of cement cost. The use of recycled concrete aggregates saves only about 1% CO2 emission compared to regular concrete while fly ash saves more than 28.5% and wood ash saves almost 24.5%. They can replace natural aggregates up to 100%, but there is only a 5% saving. In addition, an equivalent cost of USD 13.47 for one cubic yard of concrete could be saved by using 30% fly ash concrete when considering reduced emitted CO2eq from the material production.
29
Zhang, Zhiyin. "Review on the Role of Ultra-fine Fly Ash on the Performance of Concrete". Journal of Engineering Research and Reports 25, nr 7 (4.08.2023): 94–100. http://dx.doi.org/10.9734/jerr/2023/v25i7942.
Pełny tekst źródłaStreszczenie:
Fly ash is mainly the solid waste emitted by coal-fired fossil fuel power stations, which is collected through the flue gas emitted. At present, the comprehensive utilization of fly ash has been widely promoted and applied in actual production. The application of fly ash to concrete can not only improve the strength of concrete, but also save cement. However, its hydration rate is slow, and the incorporation of concrete will reduce the early strength of concrete. In order to improve the activity and other properties of fly ash, ultrafine fly ash with small particle size is obtained by grinding fly ash. Ultrafine fly ash has finer particle size than fly ash and larger spherical shape than original fly ash. Water demand decreases, density increases and activity increases. It can better fill the cement void, improve the internal compactness of concrete, and improve the interface structure of materials. Research has shown that adding 10% to 20% fly ash can achieve better performance than conventional concrete. For higher fly ash content, the strength decreases with the increase of fly ash content.
30
Jatoliya, A., M. Mishra i T. J. Saravanan. "Use of recycled aggregate and fly ash in the development of concrete composite". Proceedings of the 12th Structural Engineering Convention, SEC 2022: Themes 1-2 1, nr 1 (19.12.2022): 223–28. http://dx.doi.org/10.38208/acp.v1.501.
Pełny tekst źródłaStreszczenie:
Continuous economic growth poses severe problems of waste disposal for civil engineering construction and demolition works. In this research work, recycled aggregate (RCA) and fly ash in concrete composites for pavements are presented. The approach adopted here is to replace a large amount of normal aggregates (NA) with recycled aggregate, obtained from various crushed concrete and partial substitution of Portland cement by fly ash to develop rigid pavement concrete. A preliminary test is conducted on the materials which are used in the development of concrete pavement. Results have satisfactory results as per Indian standard guidelines. The compressive strength is determined at a proportion of fly ash varying from 0 to 40%, which gives a wide range of adding fly ash and recycled aggregate to achieve the aggregate's better mechanical property. It also determines the concrete's long-term flexural strength by partially replacing the RCA and fly ash, an important parameter in rigid pavement design. At 28 days and 56 days, the compressive strength is determined for different fly ash and recycled aggregate proportions, and concrete having more fly ash shows better results at 56 days’ compressive strength.
31
Bespolitov, D. V., N. A. Konovalova, O. N. Dabizha, P. P. Pankov i E. A. Rush. "Influence of the Mechanical Activation of Fly Ash on Strength of Ground Concrete Based on Waste Production". Ecology and Industry of Russia 25, nr 11 (16.11.2021): 36–41. http://dx.doi.org/10.18412/1816-0395-2021-11-36-41.
Pełny tekst źródłaStreszczenie:
The possibility of utilization of inactive fly ash in road concrete compositions by bringing of ash into a non-equilibrium condition with increased reactivity by mechanical activation in a vibration eraser is investigated. It was revealed that the optimal content of binder and fly ash in samples of soil concrete was 8 and 10 wt. %, respectively. It is shown that, due to mechanical activation, the specific surface area of fly ash increases by 2 times, dehydration and carbonization occur and silicon is replaced by aluminum in silicon-oxygen tetrahedra. It has been established that an increase of the content of crystalline carbonate phases is the reason for an increase in the strength of ground concrete. It is determined that the introduction of mechanoactivated fly ash into the composition of soil concretes contributes to increasing their physical and mechanical characteristics to the maximum strength grade M100. This indicates the competitiveness of ground concrete and the possibility of direct use of inactive fly ash in road construction.
32
Hope, Brian B. "Fly ash in concrete". Canadian Journal of Civil Engineering 13, nr 6 (1.12.1986): 771. http://dx.doi.org/10.1139/l86-115.
Pełny tekst źródła
33
Park, Cheol Woo. "Recycling of Waste Concrete and Fly Ash for Recycled Aggregate Concrete: Fundamental Characteristics Evaluation". Materials Science Forum 620-622 (kwiecień 2009): 255–58. http://dx.doi.org/10.4028/www.scientific.net/msf.620-622.255.
Pełny tekst źródłaStreszczenie:
As the amount of waste concrete has been increased and recycling technique advances, this study investigates the applicability of recycled concrete aggregate for concrete structures. In addition fly ash, the industrial by-product, was considered in the concrete mix. Experimental program performed compressive strength and chloride penetration resistance tests with various replacement levels of fine recycled concrete aggregate and fly ash. In most case, the design strength, 40MPa, was obtained. It was known that the replacement of the fine aggregate with fine RCA may have greater influence on the strength development rather than the addition of fly ash. It is recommended that when complete coarse aggregate is replaced with RCA the fine RCA replacement should be less than 60%. The recycled aggregate concrete can achieve sufficient resistance to the chloride ion penetration and the resistance can be more effectively controlled by adding fly ash. It I finally conclude that the recycled concrete aggregate can be successfully used in the construction field and the recycling rate of waste concrete and flay ash should be increased without causing significant engineering problems.
34
Quan, Hongzhu, i Hideo Kasami. "Experimental Study on Effects of Type and Replacement Ratio of Fly Ash on Strength and Durability of Concrete". Open Civil Engineering Journal 7, nr 1 (26.07.2013): 93–100. http://dx.doi.org/10.2174/1874149520130708004.
Pełny tekst źródłaStreszczenie:
This paper presents the test results of a series of experimental studies on the effects of type and replacement ratio of fly ash on strength and durability of concrete. 3 types of fly ashes are used in this research, the specific surface area of which are 5070 cm2/g, 3760 cm2/g and 1970 cm2/g, respectively. They satisfy the requirement of Type-1, Type-2 and Type-4 fly ashes in Japanese Industrial Standard. Ordinary Portland cement, river sand, crushed sandstone, water reducer and air entraining agent are used as well. The results indicate that drying shrinkage of concrete is reduced when cement is partially replaced by fly ash. Comparatively, Type-2 fly ash's addition leads to a more effective drying shrinkage reduction, and those with replacement ratios result in larger dry shrinkage reduction. Carbonation increases with the increase of replacement ratio of fly ash, and concrete with Type-1 fly ash has higher carbonation than those with Type-2 and Type-4 fly ashes. The carbonation rate is found to be linear with water cement ratio regardless of replacement ratio of fly ash. Durability factor decreases with the replacement ratio of fly ash after 300 freezing and thawing cycles. Also, durability factor of concrete containing Type-1 and Type-2 fly ashes with replacement ratio of 25% to 55% is higher than 80%. However, those with Type-4 fly ash show lower durability factor after 300 cycles. Concretes with 70% replacement of fly ash are not durable in spite of the type of fly ash or specific surface area.
35
YAMAMOTO, Junki, Hiroyuki KAWAKAMI, Toyoharu NAWA i Akira NISHIDA. "ESTIMATION OF FLY ASH CONTENT IN FLY ASH CONCRETE". Cement Science and Concrete Technology 64, nr 1 (2010): 147–53. http://dx.doi.org/10.14250/cement.64.147.
Pełny tekst źródła
36
Mohammad Iliyas Mohammad Sayeed, Dr. Vikram A. Patil i Somanagouda R. Takkalaki. "An Experimental Study on Short Term Durability and Hardened Properties of Baggasse Ash and Fly Ash Based Geo Polymer Concrete". International Journal of Engineering and Management Research 11, nr 1 (27.02.2021): 222–27. http://dx.doi.org/10.31033/ijemr.11.1.30.
Pełny tekst źródłaStreszczenie:
This project reports the comparison of bagasse ash and fly ash-bagasse ash based on geopolymer concrete. In which cement is fully replaced by pozzolanic material that is rich in silicon and aluminium like fly ash and bagasse ash referred to as “Geopolymer concrete” which is a contemporary material. Geopolymer concrete was actually manufactured by reusing and recycling of industrial solid wastes and by products. Fly Ash, a by-product of coal obtained from the thermal power plant is plenty available worldwide. Fly ash is used as ingredients in concrete which enhance the properties of concrete and utilization of fly ash is helpful for consumption. Bagasse ash is a final waste product of sugar obtained from the sugar mills. The base material, viz. fly ash and Bagasse ash, is activated by alkaline solution that is sodium hydroxide and sodium silicate to produce a binder which is rich in silica and aluminium. Sample 1 is cement. It is replaced by 100% fly ash geopolymer concrete and trial 2 is 10%, 30% & 50% replaced by Bagasse ash in Geopolymer concrete . The project presents the strength and durability of Bagasse ash based Geopolymer concrete and fly ash and Bagasse ash based Geopolymer concrete.
37
Wu, Xiang Hao, Yong Xin Yao, Xing Wei Yin i Pan Yuan. "Influence of Adding Lime Dust on Compressive Strength and Frost Resistance of Fly Ash Recycled Concrete". Advanced Materials Research 671-674 (marzec 2013): 1813–16. http://dx.doi.org/10.4028/www.scientific.net/amr.671-674.1813.
Pełny tekst źródłaStreszczenie:
The influence of part of fly ash replaced with lime dust on fly ash recycle concrete compressive strength and frost resistance is investigated by compression tests and rapid frost-thawing test. The experimental results show that part of fly ash replaced with lime dust will reduce the early compressive strength of the fly ash recycled concrete; the right amount of lime dust replacing fly ash can raise the latter compressive strength of fly ash recycled concrete, the best replacement proportion is 10%. The anti-frozen capacity of fly ash recycled concrete will reduce by replacing part of fly ash with lime dust, and the amplitude reduction of anti-frozen capacity of fly ash recycled concrete in seawater is greater than the amplitude reduction in sulfate solution and in freshwater.
38
Rahman, Mohammad Junaedy, Anas Arfandi i Gangsar Pangestu. "Is it possible to achieve High-Quality Concrete with Partial Substitution of Fly Ash?" IOP Conference Series: Earth and Environmental Science 1209, nr 1 (1.07.2023): 012004. http://dx.doi.org/10.1088/1755-1315/1209/1/012004.
Pełny tekst źródłaStreszczenie:
Abstract This study aims to determine the characteristics of high-quality concrete using fly ash as a partial replacement for PCC cement. Tests include slump testing, density factor and concrete compressive strength testing. Two variations of the concrete mix are made, namely the variation without fly ash and the 15% fly ash mixture. The results of this study indicate that the characteristics of concrete with fly ash substitution require the same amount of water as the concrete without fly ash to achieve the desired slump value. The density factor values obtained are also the same. In the concrete compressive strength test, the variation of the 15% fly ash mixture was higher than that of the 0% fly ash mixture.
39
Wang, Qiang, Pei Yu Yan i Reng Guang Liu. "Effects of Blended Steel Slag-Superfine Fly Ash Mineral Admixture and Ordinary Fly Ash on the Properties of Concrete". Materials Science Forum 743-744 (styczeń 2013): 323–28. http://dx.doi.org/10.4028/www.scientific.net/msf.743-744.323.
Pełny tekst źródłaStreszczenie:
The effects of blended steel slag-superfine fly ash mineral admixture and ordinary fly ash on the properties of concrete were compared in this study. The results show that, in the case of the same adding amount, blended steel slag-superfine fly ash mineral admixture and ordinary fly ash have similar effects on the early strength and chloride ion permeability of concrete. Blended mineral admixture has higher ability to improve the late strength of concrete than ordinary fly ash. Paste and concrete containing blended mineral admixture have smaller porosities than that containing ordinary fly ash. Blended steel slag-superfine fly ash is an ideal mineral admixture for concrete.
40
Gull, Sarvat, Shoib B. Wani i Ishfaq Amin. "Exploring optimum percentage of fly-ash as a replacement of cement for enhancement of concrete properties". Challenge Journal of Concrete Research Letters 11, nr 1 (25.03.2020): 16. http://dx.doi.org/10.20528/cjcrl.2020.01.003.
Pełny tekst źródłaStreszczenie:
Researchers and decision makers are continuously looking out to determine the potential and effectiveness of fly-ash as a partial replacement of cement in concrete. The current study is carried out to check the optimum or nearly optimum quantity of fly-ash with which cement should be replaced to get most of the properties of concrete enhanced and to give the idea about the quantities of fly-ash that can be used in a better way and better cause so that a proper management scheme of its usage and disposal can be implied. Further, a comparison is given between normal concrete and fly-ash concrete to show the properties which can be enhanced by proper utilization of fly-ash as a partial replacement of cement. After carrying out the lab experiments, it has been seen that the replacement of fly-ash in concrete has resulted in general increase in compressive strength, flexural strength and splitting tensile strength up to 15% replacement and after then the strength is decreased considerably than that of normal concrete. Addition of fly-ash in concrete has resulted in decrease in the water absorption of concrete and hence decreases in permeability of concrete. There is a progressive increase in workability with increase in percentage of fly-ash in concrete. The current study has led to a conclusion that in order to achieve best results in use of fly-ash concrete, the fly-ash used for replacing cement in concrete should have the required properties as specified by the standards and proper techniques of processing fly-ash as well as mixing of fly-ash with cement must be employed.
41
Wu, Chung-Hao, Chung-Ho Huang, Yu-Cheng Kan i Tsong Yen. "Effects of Fineness and Dosage of Fly Ash on the Fracture Properties and Strength of Concrete". Applied Sciences 9, nr 11 (31.05.2019): 2266. http://dx.doi.org/10.3390/app9112266.
Pełny tekst źródłaStreszczenie:
This study focuses on evaluating the effects of the fineness of fly ash on the strength, fracture toughness, and fracture resistance of concrete. Three fineness levels of fly ash that respectively pass sieves—no. 175, no. 250, and no. 32—were used. In addition to the control concrete mixture without fly ash, two fly ash replacement levels of 10% and 20% by weight of the cementitious material were selected for the concrete mixture. The experimental results indicate that the compressive strength of the fly ash concrete decreases with the increase in the replacement ratio of fly ash but increases in conjunction with the fineness level of fly ash. The presence of finer fly ash can have beneficial effects on the fracture energy (GF) of concrete at an early age (14 days) and attain a higher increment of GF at a later age (56 days). The concrete containing finer fly ash was found to present larger critical stress intensity factors (KSIC) at various ages, and the KSIC also increases in conjunction with the fineness levels of fly ash.
42
Kumar, Anil. "Effect of Admixtures (Fly Ash and Super Plasticizer) on Performance of Concrete". International Journal for Research in Applied Science and Engineering Technology 11, nr 6 (30.06.2023): 1208–16. http://dx.doi.org/10.22214/ijraset.2023.53713.
Pełny tekst źródłaStreszczenie:
Abstract: This research is conducted to study the performance of concrete mix containing Class-C Fly ash and P250 super plasticizer. The concrete mix are also proportioned to have various proportion of cement replacements by fly ash ranging from 10% to 30% by weight and super plasticizer PC250 from 0.5% to 1.5% by weight of cement. The performance of concrete is evaluated with respect to workability and compressive strength by Destructive and Non destructive test (rebound number). At 28 day. Concrete mix containing fly ash and super plasticizer shows consistently higher compressive strength compared to concrete with only fly ash and without fly ash. It has been observed that by addition of fly ash the initial compressive strength is lower because of unhydrated cement, since the addition of fly ash lowers the rate of hydration of cement. According to the analysis of results show that class- C fly ash could be substituted for cement replacement, as the concrete with fly ash 30% and super plasticizer shows 34.19% more strength as compared to non fly ash concrete. Similarly increase in workability also observed upto 240mm slump value.
43
A K, Dasarathy, M. Tamil Selvi, D. Leela i S. Kumar. "Self Compacting Concrete – an Analysis of Properties using Fly Ash". International Journal of Engineering & Technology 7, nr 2.24 (25.04.2018): 135. http://dx.doi.org/10.14419/ijet.v7i2.24.12018.
Pełny tekst źródłaStreszczenie:
Self compacting concrete has ability involves not only high deformability of paste or mortar, but also resistance to segregation between coarse aggregate and mortar when the concrete flows through the confined zone of reinforcing bars. Several researchers have employed the different methods to achieve self- compactability. In recent years, self-compacting concrete (SCC) has gained wide use for placement in congested reinforced concrete structures with difficult casting conditions. For such applications, the fresh concrete must possess high fluidity and good cohesiveness. The initial results of an experimental program aimed at producing and evaluating SCC made with high volumes of fly ash are presented and discussed. Nine SCC mixtures and one control concrete were investigated in this study. The content of the cementitious materials was maintained constant (400 kg/m3), while the water / cementitious material ratios ranged from 0.35 to 0.45. The self-compacting mixtures had a cement replacement of 40,50 and 60% by Class F fly ash. Tests were carried out on all mechanical properties of hardened concretes such as compressive strength were also determined. The self-compacting concretes developed a 28- day compressive strengths ranging from 26 to 48 MPa. The results show that an economical self-compacting concrete could be successfully developed by incorporating high-volumes of Class F fly ash. The present project investigates the making of self-compacting concrete more affordable for the construction market by replacing high volumes of Portland cement by fly ash. The study focuses on comparison of fresh properties of SCC containing varying amounts of fly ash with that containing commercially available admixture. Test result substantiate the feasibility to develop low cost SCC using Class F fly ash.
44
Zhang, Liang Liang, Li Qun Wu, Jian Xin Yang i Kang Zhang. "Effect of Fly Ash on Creep of High Performance Concrete Used in Bridge". Applied Mechanics and Materials 204-208 (październik 2012): 2192–95. http://dx.doi.org/10.4028/www.scientific.net/amm.204-208.2192.
Pełny tekst źródłaStreszczenie:
W/C ratio and the quantity of fly ash added have obvious influence on creep of high performance concrete. Effect of different quantities of fly ash on creep of high performance concrete of different W/C ratios used in bridge is studied in this research whose results reflect that creep value reduces along with reduction of W/C ratio at a certain quantity of fly ash added. Adding fly ash restrains creep on the whole, however, the degree depends on the quantity of fly ash added. Creep value of high performance concrete mixed with class-I fly ash at blend ratio of 12~40% is lower than that of standard concrete and fly ash at blend ratio of 18% has the best effect. Creep value in 365d is 51% of that of standard concrete at fly ash blend ratio of 18%, while at fly ash blend ratio of 40%, creep value in 365d is lower than that of standard concrete but higher than that of concrete at other blend ratios. It is generally considered that inhibition of creep of high performance concrete begins to fall beyond blend ratio of 30%.
45
Wathoni, Muhammad Munawir, Dwi Sabda Budi Prasetya i Dwi Pangga. "Uji Mekanik Bata Ringan Berbahan Dasar Limbah Pengolahan Emas dengan Variasi Limbah Batu-bara dan Semen". Jurnal Penelitian dan Pengkajian Ilmu Pendidikan: e-Saintika 2, nr 1 (31.12.2018): 41. http://dx.doi.org/10.36312/e-saintika.v2i1.110.
Pełny tekst źródłaStreszczenie:
[Title: The Mechanical Test of Lightweight Brick Made from Gold Processing Waste with Variations in Coal and Cement Waste]. The purposes of this research are to make lightweight concrete using waste processing of gold with variation fly ash and cement the better than conventional concrete. The value of this research has tested mechanics which comprises density, porosity and strength. The research has done with some stage are: 1) Make lightweight concrete using LPE with variation fly ash and cement. 2) Characterization of the samples which comprise density, porosity and the strength, 3) Analysis of tested mechanical lightweight concrete. The value of lightweight concrete to make with variation composition fly ash and cement in a series are: (0/100), (5/95), (10/90), (15/85), (20/80) who are in volume. To make lightweight concrete with composition foam and water controlled as much as 10 ml and 150 ml at all of the sample. So we get the density value of lightweight concrete without fly ash is 1.61. In lightweight concrete with fly ash, we get the minimum density of lightweight is 1.15. The porosity value of lightweight concrete without fly ash is 13.6%, and the porosity value of lightweight concrete with fly ash is 8.0%. The compressive strength of lightweight concrete without fly ash is 1.629 MPa and the compressive strength of lightweight concrete with fly ash is 1.772 MPa. The value shown to process waste processing of gold with variation fly ash and cement to be lightweight concrete can get mechanical in character of lightweight to be better than conventional concrete.
46
Guo, Xiao Yan, i Run Xia Hao. "Anti-Permeability and Resistance Carbonization Test Study High Performance Concrete with High Content of Fly Ash". Applied Mechanics and Materials 357-360 (sierpień 2013): 1106–9. http://dx.doi.org/10.4028/www.scientific.net/amm.357-360.1106.
Pełny tekst źródłaStreszczenie:
Anti-penetrability performance test and carbonization test of high performance concrete with high volume fly ash were done and were compared with normal concrete. Test illustrated that filled the concrete dense function of high quality fly ash were superior to common concrete. Average carbonation depth of high quality fly ash concrete was slight inferior to carbonation depth of the common concrete. Keywords: anti-penetrability performance; fly ash; high performance concrete; carbonation
47
Poudyal, Lochana, Kushal Adhikari i Moon Won. "Nano Calcium Carbonate (CaCO3) as a Reliable, Durable, and Environment-Friendly Alternative to Diminishing Fly Ash". Materials 14, nr 13 (2.07.2021): 3729. http://dx.doi.org/10.3390/ma14133729.
Pełny tekst źródłaStreszczenie:
Fly ash is widely used in the cement industry to improve the performance and durability of concrete. The future availability of fly ash, however, is a concern, as most countries are inclining towards renewable energy sources as opposed to fossil fuels. Additional concerns have been raised regarding the impact of strict environmental regulations on fly ash quality and variability. This paper, therefore, evaluates if nano calcium carbonate (nano CaCO3) can be used as an alternative to fly ash. This paper presents comprehensive testing results (fresh, hardened, and durability) for OPC (Ordinary Portland Cement) and PLC (Portland Limestone Cement) concretes with 1% nano CaCO3 and compares them to those for concretes with fly ash (both Class F and C). Compared to concretes with fly ash, OPC and PLC with nano CaCO3 presented improved testing results in most cases, including later age strength, permeability, and scaling resistance. As nanotechnology in concrete is a relatively new topic, more research on the efficient use of nanotechnology, such as for proper dispersion of nano CaCO3 in the concrete, has potential to offer increased benefits. Further, nano CaCO3 is environmentally and economically viable, as it has the potential to be produced within the cement plant while utilizing waste CO2 and generating economic revenue to the industry. Thus, nano CaCO3 has the potential to serve as an alternative to fly ash in all beneficial aspects—economic, environmental, and technical.
48
Quan, Hong Zhu. "Research on Improving the Durability of Fly Ash Concrete". Advanced Materials Research 250-253 (maj 2011): 626–29. http://dx.doi.org/10.4028/www.scientific.net/amr.250-253.626.
Pełny tekst źródłaStreszczenie:
The purpose of this study was to improve the durability of fly ash concrete. As a result, by making fly ash concrete into non-air-entraining type and using durability improving admixture, the compressive strength of fly ash concrete increases 10%~30%, reducing initial compressive strength defects; drying shrinkage is controlled at 60% compared to when the mixture is not added; carbonation of fly ash concrete can be considered roughly proportional to water-cement ratio regardless of water-binder ratio or fly ash replacementratio; the freeze damage resistance improves for 2 weeks curing in air (drying process). Finally, by making fly ash concrete from non-air entraining type and using durability improving admixture, the difficulty of controlling air content in fly ash concrete is reduced and quality management is simplified.
49
Kim, Tae Wan, Jong Yeon Lim, Xiao Yong Wang i Yi Han. "Support Vector Machine (SVM)-Based Optimal Design Procedure of Fly Ash Blended Concrete". Key Engineering Materials 894 (27.07.2021): 103–8. http://dx.doi.org/10.4028/www.scientific.net/kem.894.103.
Pełny tekst źródłaStreszczenie:
A support vector machine (SVM) is widely used for predicting the properties of fly ash blended concrete. However, the studies about the optimal design of fly ash blended concrete based on SVM are very limit. This study shows an SVM-based optimal design procedure of fly ash blended concrete. First, we built an SVM model and evaluated the compressive strength of fly ash blended concrete considering the effects of water to binder ratio, fly ash replacement ratio, and test ages. Second, we made parameter studies based on the SVM model. The parameter studies show that fly ash can improve the late age strength of concrete. This improvement is obvious for concrete with lower water to binder ratio. The optimal fly ash replacement ratio increases as the water to binder ratio decreases.
50
Huang, Jin, i Hua You Su. "Application for Fly Ash Concrete in Pavement Engineering". Advanced Materials Research 510 (kwiecień 2012): 817–21. http://dx.doi.org/10.4028/www.scientific.net/amr.510.817.
Pełny tekst źródłaStreszczenie:
When the ordinary concrete is added to fly ash, the slump of concrete is increased and the workability and pumpability are also improved, which can meet the design requirement, reduce project costs, protect environment and save resources. Based on evaluation of the basic performance for raw materials of fly ash concrete, the improved mix design method for fly ash concrete is proposed. And then it is tested in practical project to verify the workability and feasibility and meanwhile some construction attentions are proposed. The results show that the fly ash can significantly improve the workability of cement concrete. The early strength of fly ash concrete is lower than ordinary concrete, but after 28 days, the compressive strength is similar with ordinary concrete, which provides a reference for design and construction of fly ash concrete.