Percentage Of Fly Ash Research Articles

Model Technics to Predict the Impact of the Particle Size Distribution (PSD) of the Sand on the Mechanical Properties of the Cement Mortar Modified with Fly Ash

Despite many of the research studies on the effect of the particle size distribution of the sand and fly ash content on the mechanical behavior of the cement mortar, there has not been a comprehensive study investigating the effect of particle size distribution curve corresponding to 10% of finer (d10), fly ash content, curing time, sand particle size distribution properties (d10), and water to cement ratio (w/c) on the compressive (σc), tensile (σt), and flexural (σf) strengths of cement mortar. Therefore, this study investigates the subject which could be beneficial for the geotechnical and building and construction field. In this study, more than 1000 data on the mechanical properties of the cement mortar modified with different percentages of fly ash varied from 5 to 75% (by dry weight of the cement) collected from the literature. Statistical analysis and modeling were performed on the collected data. Vipulanandan p-q model was used and compared to the Logistic Growth model to predict the particle size distribution of sands used in the cement mortar. The water to cement ratio (w/c) of the cement mortar ranged between 0.20–0.80 percent and the compressive strength (σc), tensile strength (σt) and flexural strength (σf) of cement mortar modified with fly ash up to 90 days of curing were ranged between 15–88 MPa, 0.4–5 MPa, and 1–10 MPa, respectively. Vipulanandan correlation model was also used and compared with the Hoek–Brown model to correlate the mechanical properties of cement mortar modified with fly ash. The analysis and modeling results of the present study showed that there is a good relationship between the compressive strength (σc) with w/c, curing time, fly ash content and d10. Based on the coefficient of determination (R2) and root mean square error (RMSE) the compressive strength (σc), flexural strength (σf) and tensile strength (σt) of cement mortar quantified well as a function of w/c, the percentage of fly ash, curing time, and d10 using nonlinear relationship.

Material aspects of high performance concrete

High performance concrete envisages the better performance concrete in terms of strength and durability properties by the quality of constituent materials. The study emphasis on effect of mineral admixtures such as fly ash and silica fume in high performance concrete. The high performance concrete of grade M60 is prepared with replacement of 10%, 20% and 30% of cement by fly ash and 2 % and 4% of cement by silica fume as mineral admixtures of desired mix proportions as per IS 10262-1982. The chemical admixture of conplast SP430, superplasticizer of 1% is added to ensure better workability for high performance concrete mix. The mechanical properties like workability, compressive strength and split tensile strength for all different cases were studied and the results are compared to find the optimum performance of fly ash and silica fume content. The optimal percentage of fly ash is about 20% with 4% silica fume to have better strength properties.

Accuracy of maturity functions’ strength estimates for fly ash concretes cured at elevated temperatures

The effect of elevated curing temperature on the strength development of concrete mixes with fly ash (FA) has been investigated for strength grades C32/40 and C55/67. Percentages of fly ash in the total binder were 15, 30 and 45 per cent. High curing temperatures have a beneficial effect on the early age strength but a detrimental effect on the long-term strength development. Fly ash concrete mixes have been shown to be less sensitive to curing at high temperatures than Portland cement (PC) concretes and this was reflected in their lower “apparent” activation energies. The accuracy of strength estimates obtained from maturity functions was examined. The temperature dependence of the Nurse-Saul function, i.e. the concrete strength gain rate varies linearly with temperature, was not sufficient to account for the improvement in early age strengths resulting from high curing temperatures. The Arrhenius based function, on the other hand, overestimated them because of the detrimental effect of high curing temperature on strength starting from a very early age. Both functions overestimate long term strengths as neither accounts for the detrimental effect of high curing temperatures on the ultimate compressive strength.

Use of Natural Pozzolanic Material as Partial Replacement Ordinary Portland Cement (OPC) in Concrete

Fly ash is a powder material of burned coal from thermal power stations which produces cementitious and pozzolanic material. Commonly use of fly ash in concrete for building construction contributes conducive environmental and also reduces the effect of pollutant in site project. Therefore, this study was conducted to investigate the use of fly ash as partial replacement of cement in concrete as a mean of producing more environmental friendly concrete. The content of fly ash as partial replacement of ordinary portland cement(OPC) is investigated by weight accordingly in range 0%(without fly ash), 10%, 20% and 30% for grade 25. The chemical composition of fly ash was determine using X-ray Fluorescence (XRF). The scanning electron microscope (SEM) was used to determine particle size, shape and texture of fly ash. The mix proportion of concrete was determine using mix design method according to British Standard. The workability of the fresh concrete mixture was evaluated using slump test while compressive strength of cubes concrete was evaluated at 7, 14, 28 and 56 days. A total of 48 cubes concrete with size 100mmx100mmx100mm were made. The optimum compressive strength at all ages of testing was obtained at 10% replacement. Workability decreased with an increased in replacement percentage of fly ash. The results therefore show that fly ash as pozzolanic materials can be used to partially replace ordinary portland cement in production of concrete.

Characterization, mechanical and wear properties of Al6061/Sicp/fly ashp composites by stir casting technique

Composite materials can be modified to offer additional mechanical and barrier properties. This work presents the manufacturing processes by the stir casting method of a novel Al6061 composite with 10% SiC and 5% Flyash (50 μm size). Experimental studies are analyzed about the mechanical properties of SiC/FA reinforced Al6061. Investigations with a hardness tester on Vickers showed that the composite had increased hardness. For Al6061 and the novel composite Al6061 + SiC/Flyash with a Pin on a disc tribometer, wear characteristics were investigated for load ranges of 1–2 Kg and velocity differing from 100 to 500 rpm. The effect on the wear of the novel composite of critical parameters such as load and velocity was present with an analysis of sensitivity. The results found are promising, showing a lower wear rate to the novel composite. The weight percentage of SiC particulates with a constant weight percentage of Fly Ash(FA) in the aluminum matrix, the mechanical properties such as hardness and tensile strength have been improved.

Effect of process parameters on WEDM of Al – Fly ash composites using Taguchi Technique

In this modern era, in some aspects of our lives, we all rely on composite materials. Aluminum matrix composites (AMCs) consist of aluminium alloy (LM6) as matrix and 3, 6 and 9 percentage of particulate fly ash as reinforcement material was manufactured by the Stir casting process. WEDM trials were performed on AMCs using Taguchi Technique implementing the L 27 orthogonal array. The influence of process parameters on MRR was investigated using S/N analysis. Analysis of variance (ANOVA) was carried out to analyse the importance of the input parameters concerning the basic features of the WEDM mechanism and the contribution of the process parameters. Confirmation experiments were conducted to confirm the enhancement of the determined values with the optimum combination. Gap Voltage (62.98%) has the largest statistical influence on composite MRR led by Pulse off Time (17.25%) and Pulse on Time (16.67%).

Study on Partial Replacement of Sand with Fly Ash in Concrete Mixes Based on Pozzolanic Cementing Efficiency to the Strength-Weight and Cost-Strength Ratio

The utilization of fly ash as sand partial replacement in concrete mix is an alternative solution for the depletion of sand resources in the Special Region of Yogyakarta. This research evaluates the effect of sand partial replacement with fly ash to the strength-weight and cost-strength ratio of concrete mixes. The strength-weight ratio was used for mechanical evaluation with higher value considered as better, while cost-strength ratio indicates its economic efficiency with lower value means more efficient. Four groups of test specimens with different amounts of fly ash were evaluated for its mechanical performance and economic efficiency. Various percentages of fly ash, sequentially 0%, 20%, 35%, and 50% were implemented in the mixes based on partial weight replacement of its components and the water-binder ratios were calculated based pozzolanic cementing efficiency method. The compressive strength was evaluated on 14 concrete cylinders with 150mm diameter and 300mm length for each variant that cured in 28 days water immersion. Test results shows that fly ash addition tend to reduce material cost and density of concretes, yet the compressive strength was not lower compared to normal concrete. Therefore, fly ash added concrete can be justified as better in mechanical performance and economically more efficiency.

The Effect of Combining Coal Fly Ash and Lokan Shells As Filler Towards The Mixture Of Asphalt Concrete Wearing Course

Sustainable construction is expected to create a quality environment so that environmental sustainability is maintained. The use of coal as fuel for PLTU have a negative impact on the environment, because it produces waste in the form of fly ash and bottom ash. Lokan freshwater is widely used as a food ingredient. This research study a mixture of AC-WC asphalt using coal fly ash and lokan shell ash as a filler. Research is needed to determine the durability and performance of the pavement that uses these waste materials by using asphalt pen 60/70 as a binder. This study uses Marshall Method and using three variations in the percentage of coal fly ash and lokan shell ash to the total filler. The highest stability obtained at V1 with a value of 1,389.158 kg. Marshall test conducted on the AC-WC blend on OAC for the mixture variation of V1, V2, V3, disclosed that Stability, flow, MQ, VMA and VFB values were acquiescent to the required specification. For the value of VIM on V1 and V3 were not acquiescent to the required spesification. The coal fly ash and lokan shells as filler recommended for alternative material on a mixture of AC-WC.

A microstructure exploration and compressive strength determination of red mud bricks prepared using industrial wastes

The consensual view among researchers concerning building with industrial by-products is that the utilization of by-products represents green technology and sustainable development. The current investigation focuses on the utilization of an assortment of by-products for the production of bricks. The by-products include Red Mud (RM), Fly ash (FA), and Ground Granulated Blast Furnace Slag (GGBS) combined in different proportions with lime. The Red Mud employed ranged from 100% to 60% with a decrement of 10%, whereas Fly ash and GGBS varied between10% and 40% with an increment of 10%. Bricks produced from two methods namely, ambient curing and firing methods, were tested as per IS standards/ASTM norms, on both the materials and the composites of bricks. XRD, XRF, and SEM focused on both the raw materials and the composites. Because geopolymer materials are partially amorphous materials with complex composition, understanding the structural characteristics of geopolymers is opined as intricate. The results of the investigation show that the compressive strength of the bricks increased with the increment in the percentage of Fly ash and GGBS. The compressive strength of Red Mud-GGBS fired bricks attained maximum strength of 7.56 MPa.

Metakaolin Geopolymer Bricks and Prismsin Axial Compression

Metakaolin geopolymer bricks (MKGB) were synthesised in this investigation with different percentages of flyash (FA) and Metakaolin (MK). A desired strength of 5.5 N/mm 2 is achieved by using 50% FA and 50% MK. The bricks were tested for properties like water absorption, initial rate of absorption, efflorescence, modulus of elasticity (MOE) and modular ratio. Initial rate of absorption for the MKGB is 0.5 Kg/m 2 /min and the water absorption for MKGB is 3–5%. The Poisson’s ratio (µ) for MKGB is 0.2 and E is 2340 MPa. Metakaolin Geopolymer brick prisms (MKBP) with aspect ratios ranging between 2–5 were constructed with 1:3 cement mortar. The compressive strength and the efficiency increases with the increase in aspect ratio of the masonry. The failure pattern is splitting and crushing of bricks rather than loss of bond between mortar and MKGB.

Predicting Marshall stability and flow of bituminous mix containing waste fillers by fuzzy logic

The practice of using different non-biddable wastes in place of conventional filler is successively extended nowadays, leading it hard to predict the properties of modified bituminous mixes. The present work aims to explore the effect of using rice husk ash (RHA) and fly ash (FA) as alternative filler in place of conventional filler like hydrated lime (HL) on Marshall stability and flow of bituminous mix by fuzzy logic. This study involves the preparation of samples having seven different bitumen content varying from 3.5% to 6.5% with 0.5% increment. Mixtures containing 2%, 4%, 6% and 8% of HL, RHA and FA separately as filler were fabricated and compared with the control mix (i.e. mix containing 2% hydrated lime as filler). Further, the Marshall mix design procedure was followed to determine the optimum bitumen content (OBC) of each mix. Experimental results showed that the replacement of conventional filler with RHA and FA improved the Marshall properties and decreases the OBC values of the modified mix when added with 4% filler ratio. Further, for predicting the Marshall stability and flow, a Mamdani-type fuzzy inference system model was devised in Matlab toolbox using percentage bitumen, air voids, percentage of HL, RHA and FA as input and Marshall stability and flow as output. In comparison, it is realized that predicted values are closely relevant to the actual one and the prediction ability of the fuzzy logic model is suitable for getting the said values by avoiding the expensive, time consuming and repetitive laboratory tests.

Experimental study on strength and durability properties of iron scrap with flyash based concrete

Concrete is the most universally used construction material today. As concrete dries, it shrinks and is an evitable phenomenon that routinely occurs. In this investigation an attempt has been made to study the effects of different percentage of iron scrap in concrete, by the optimum percentage getting different percentage of fly ash was added and tested. Thus addition of short randomly distributed iron scrap in concrete plays an important role in enhancing the strength. The effect of short randomly oriented fibre and strength characteristics of cement oriented fibre and strength characteristics of cement concrete with aspect ratio of 100 for different of iron scrap by volume of the specimen is considered compression, split tensile, prism, durability and Dorry’s abrasion test were conducted.The use of waste steel strips produced in industrial operations in machine shops and workshops as reinforcement in concrete promises to be an exciting prospect in iron scrap concrete technology. Experimental investigations were under taken by the author to determine the behaviour of test specimen in compression and flexure. The specimens include cubes, cylinders and beams of M20 concrete with iron scrap ranging from 2.5% to 15%. From the test, it was observed that the addition of iron scrap improved the flexural strength of concrete and it is suggested as cost-effective and structurally efficient material in many Civil Engineering applications.

Characterization Study of Zinc Sulphate's Influence and Retarding Mechanism with Coarser and Finer Fly Ash Particles in Concrete

Pozzolan, a modified cementitious material, has a major impact on the construction industry. Among the different composite materials, fly ash blended cement has great part due to its abundance. In recent years, the pulverized fly ash has become the key interest among the researchers because of its improved physical properties. This makes it necessary to study the effect of fly ash blends with various chemical admixtures. This study primarily focuses on bringing the changes happening in the strength, retarding mechanism, setting time, mineralogy, and microstructure caused by the addition of Zinc Sulphate (ZnSO4) in concrete having various percentages of raw fly ash (RFA) and ultrafine fly ash (UFFA). The result shows that ZnSO4 increases the setting time by more than 60%. Also, the study indicates decreased strength in concrete because of the reduced formation of hydrated products; this phenomenon is confirmed by scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and X-ray fluorescence (XRF) analysis.

Study on conventional and microwave assisted sintering of Cu-FA composites

Abstract In this study we have diligently made efforts to reinforce Copper (Cu) with Fly Ash (FA) via Powder metallurgical path to form Cu- FA composite. We have critically investigated the effects of sintering mode on Cu-FA composite properties and variation of mechanical properties with change in weight percentage of FA in the composite. The sintering effect of Cu-FA pellets of 3, 6 and 9 wt% of FA in a microwave furnace of 2.5 GHz was compared with that processed in a conventional furnace. The elemental analysis and morphology of the prepared samples were characterized using Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDS) and optical images. Results indicated a rise in hardness values with the increase of fly ash in composite up to 6 wt% and then a drop down in value to that of pure Cu due to exposure of Cu matrix during sintering. Wear rate decreases with increase of fly ash in composite. Our results imperatively showed microwave sintered samples were observed to be superior in mechanical properties like hardness, wear resistance as well as densification response compared to their conventional counterparts.

Predicting the mechanical properties of normal and high strengths concrete modified with fly ash at different w/c ratios, and curing times

The objective of this study is to identify and quantify the effect of fly ash content (FA), water/cement ratio (w/c), and curing time (t) on the compressive and tensile strengths of concrete at different strength ranges varied from 4 to 100 MPa. More than 1000 experimental data collected from different research studies. Statistical analysis and modeling were performed on the collected data. The range of w/c ratio for modified concrete with different percentages of fly ash up to 90% (by dry weight of cement) was 0.19–0.87. Compressive strength (cs) and tensile strength (ts) were 4–100 MPa and 0.5–6 MPa respectively. Vipulanandan correlation model was used to predict the relationship between mechanical properties of concrete modified with FA. Based on the coefficient of determination (R2) and root mean square error (RMSE) the compressive strength (cs) and tensile strength (ts) of concrete as a function of w/c ratio, FA content, and curing time quantified very well using nonlinear (NLM) relationship. Based on the NLM parameters, the effect of FA was less than w/c ratio and curing time on the compressive strength of modified concrete in different strength ranges.

Retraction Note to: Artificial neural networks for prediction compressive strength of geopolymers with seeded waste ashes

In the present work, compressive strength of inorganic polymers (geopolymers) made from seeded fly ash and rice husk bark ash has been predicted by artificial neural networks. Different specimens were subjected to compressive strength tests at 7 and 28 days of curing. One set of the specimens were cured at room temperature until reaching to 7 and 28 days, and the other sets were oven-cured for 36 h at the range of 40–90 °C and then room cured until 7 and 28 days. A model based on artificial neural networks for predicting the compressive strength of the specimens has been presented. To build the model, training and testing using experimental results from 120 specimens were conducted. The data used in the multilayer feed-forward neural networks models are arranged in a format of six input parameters that cover the percentage of fine fly ash in the ashes mixture, the percentage of coarse fly ash in the ashes mixture, the percentage of fine rice husk bark ash in the ashes mixture, the percentage of coarse rice husk bark ash in the ashes mixture, the temperature of curing, and the time of water curing. According to these input parameters, in the neural networks model, the compressive strength of each specimen was predicted. The training and testing results in the neural networks model have shown a strong potential for predicting the compressive strength of the geopolymer specimens.

Effect of Temperature on Morphology, Phase Transformations and Thermal Expansions of Coal Fly Ash Cenospheres

Cenospheres are small, hard-shelled hollow spheres with high silica and alumina content. These micron-sized aluminosilicate hollow spheres constitute only a small percentage of the coal fly ash (CFA) obtained from the coal combustion processes. In this study, cenospheres were separated from CFA obtained from a coal-fired power plant located in Kapar, Malaysia. The cenospheres were heated at 1000, 1200 and 1400 °C to study the changes in morphologies, compositions, phase formation and thermal expansion. The sintering temperatures were selected based on the differential scanning calorimetry (DSC) curve results. X-ray diffractometry (XRD), field emission electron microscopy (FESEM), energy dispersive spectroscopy (EDS) as well as thermogravimetry and differential scanning calorimetry analysis (TG–DSC) were used for the characterization study. The study found that the cenospheres have excellent weight stability but are thermally unstable as a result of crystallization and melting. The phase ordering process and devitrification of the amorphous aluminosilicate glass phase at high temperatures lead to the increment and enrichment of the mullite phase in cenospheres. It is suggested that a preheating treatment at 1100 °C could be used to enhance the mechanical properties and thermally stabilize the cenospheres, which make it more suitable for use as a pore-forming agent in ceramics.

Optimization of using Baturaja fly ash as a Portland Composite Cement (PCC) additive

There has been researched on the optimization of fly ash Baturaja as a cement additive PCC. The purpose of this research is to know the optimal percentage of fly ash, which can be added to the process of making PCC cement, which still produces excellent quality cement and fulfills SNI and knowing the effect of adding fly ash to physical testing and chemical testing. The test was done physically, Blaine test, setting time test and compressive strength test for three days, seven days, and 28 days. Meanwhile, chemical testing is the Loss of Ignition (LOI) test, Free Calcium Oxide (FCaO) test, and Insoluble Residue test (IR). Based on the result of research, the most optimal percentage is when adding 6% ash fly proportion. The higher the ratio of fly ash, will result in an unstable Blaine value. The higher the proportion of fly ash is added, the compressive strength will be smaller, and the setting time will be longer. Meanwhile, the higher the addition of fly ash, the value of loss of ignition, Free Calcium Oxide, and insoluble residue value will be higher.

Experimental investigations on geopolymer stabilised compressed earth products

The main objective of the study was to explore the geopolymers to produce the compressed earth bricks for building construction. The paper presents the results of experimental investigations on geopolymer stabilised compressed earth specimens. The variables considered include, alkali concentration, clay content and percentage of ground slag and fly ash. The mix proportions of the variables were varied to assess optimum dosages for producing geopolymer stabilised compressed earth bricks. The results showed that the natural clay minerals in the soil do not yield sufficient strength. Use of ground slag and fly ash as an additional source of alumina and silica resulted in sufficient strength gain for the compressed earth specimen. The geopolymer stabilised compressed earth specimens showed efflorescence due to leaching of salts and the investigations showed that the efflorescence does not affect the strength. The products formed in the geopolymer stabilised compressed earth specimens were identified by employing the FTIR, XRD and NMR techniques.

Hardened properties of concrete with different proportion of crumb rubber and fly ash

The utilisation of waste materials in concrete is one of the sustainable construction approaches introduced in the industry that can indirectly reduce the environmental issues arisen from the disposal problem of the wastes. The aim of this study is to investigate the hardened properties of rubberised pozzolanic concrete (RuPC) with different proportion of crumb rubber and fly ash as partial fine aggregate and ordinary Portland cement (OPC) replacement, respectively. The crumb rubber content replacing fine aggregate is in the range of 0% to 20% while fly ash replacing cement ranges from 0% to 30%. Testing of RuPC with different percentage of crumb rubber and fly ash were performed at the age of 28 days for density, compressive, splitting tensile and flexural strength, and were compared with properties of control specimens. Results showed that the density of RuPC decrease with increase in crumb rubber and fly ash content. The overall strength of RuPC decrease as crumb rubber content increase in which 5% crumb rubber show the least reduction in strength. Replacing 10% cement with fly ash shows improvement in the strength of RuPC when compared to specimens without fly ash, however still lower than strength of control specimen. The optimum crumb rubber replacement is 5% while fly ash is 10% to avoid significant reduction in strength.