Mixing Fly Ash Research Articles

Preparation, microstructure and property of carbonated artificial steel slag aggregate used in concrete

Artificial steel slag aggregates were prepared via carbonating the mixes of steel slag, fly ash and Portland cement, of which the microstructure, property and their impact on the performance of concrete were investigated. Calcium carbonates were the main binders in the aggregates, of which the formation yielded dense microstructures and reduced crushing values. The carbonated artificial steel slag aggregates showed very stable volumes after the autoclaving test at 216 °C. This is due to the depletion of free-CaO contained in the steel slag as a result of carbonation. Concretes with compressive strengths of up to 45.5 MPa at 28d and stable volumes were prepared with the carbonated artificial steel slag aggregates. Owing to the water absorption in the artificial aggregates, higher relative humidity and in turn less autogenous shrinkages were induced in the concrete. This work provides a novel way to utilize steel slag to produce aggregates coupled with CO2 sequestration.

ANALISIS KUAT TEKAN DAN DENSITAS BETON NON-PASIR DENGAN CAMPURAN VARIAN ABU TERBANG MENGGUNAKAN MATLAB

This study aims to determine how the properties of non-sand concrete with variations in the amount of mixing fly ash. This property was analyzed by compressive strength test. We also do calculations using the MATLAB application with interactive script methods. There are 16 numbers of test objects conducted in this study. The specimen is cylindrical with a size of 7.5 cm and a height of 15 cm. Flying ash variations used ranged from 0%, 25%, 50%, and 75%. In this research, we use 1: 6 between cement and gravel. The results of the average compressive strength obtained in the mixture of 0% fly ash are 1,172 MPa, 25% 0.871 MPa, 50% 2,367 MPa and 1,465 MPa for mixture of 75% fly ash. The best compressive strength results on the 50% fly ash mixture. The density is also affected by the mixing of this fly ash. The greater the mixing of the fly ash, the smaller the density value. Keywords: compressive strength, density, fly ash, MATLAB

Geotechnical Properties of Anthropogenic Soils in Road Engineering

The construction of a roads network consumes high amounts of materials. The road materials are required to fulfill high standards like bearing capacity and low settlement susceptibility due to cyclic loading. Therefore, crushed aggregates are the primary subbase construction material. The material-intensity of road engineering leads to depletion of natural resources, and to avoid it, the alternative recycled materials are required to be applied to achieve sustainable development. The anthropogenic soils (AS), which are defined as man-made unbound aggregates, are the response to these requirements. For the successful application of the AS, a series of geotechnical laboratory and field tests were conducted. In this article, we present the set of 58 test results, including California Bearing Ratio (CBR) bearing capacity tests, oedometric tests, and cyclic CBR tests, to characterize the behavior of three AS types and to compare its reaction with natural aggregate (NA). The AS tested in this study are recycled concrete aggregate (RCA), fly ash and bottom ash mix (BS), and blast furnace slag (BFS). The results of the tests show that the AS has similar characteristics to NA, and in some cases, like compression characteristic, RCA and BFS behave a stiffer response to cyclic loading. The test results and analysis presented here extend the knowledge about AS compressibility and AS response to cyclic loading.

Mixed precursor geopolymer synthesis for removal of Pb(II) and Cd(II)

In this study, geopolymers were prepared using a mixed precursor of coal fly ash (35 wt%) and metakaolin (65 wt%) in order to investigate the adsorption capacity for Pb2+and Cd2+ in solution. The specific surface area of the geopolymer was up to 82.8 mg/m2. The results show that the maximum adsorption capacity of the geopolymer for Pb2+ and Cd2+ removal were 164.1 and 78.2 mg/g, respectively. Mixing fly ash and metakaolin as raw materials for geopolymer synthesis not only yields an adsorbent material with excellent performance, but is also an effective way to utilize industrial waste resources.

Palm oil mill fly ash as a low-cost adsorbent for Rhodamine-B removal from industrial wastewater

In this study, the adsorption properties of Rhodamine-B (RB) on fly ash were investigated. Two different fly ashes conditions, including raw fly ash and activated fly ash, were selected for the adsorption experiment. The adsorption process is conducted by mixing fly ash 0.5; 1; 1,5 and 2g/L with the temperature of 30°C; 35°C; 45°C. The results showed that the HCl activation will enhance the MB adsorption capacity of fly ash, the higher the mass of adsorbent, and the higher mixing temperature, the better the performance of adsorbent is. Then, the great conditions for reducing RB with adsorbent mass 2g/L at temperature of 45°C, with a removal efficiency 90,54%

Improving strength of porous asphalt: a nano material experimental approach

Porous asphalt (PA) has potential to be utilized in many urban area in Indonesia which often faced high street runoff during rainy season. PA is an environmentally friendly tool for stormwater management. A typical porous pavement has an open-graded surface over an underlying stone recharge bed. The water drains through the porous asphalt and into the stone bed, then, slowly, infiltrates into the soil. However, despite of the benefit of porous asphalt, there is still weaknesses, such as less of service life than dense-graded asphalt due to its lower durability and strength. In order to improve durability and strength of PA, this study investigates the effect of using fly ash (FA) class F in porous asphalt (PA) mixture as replacement of common filler. Since asphalt pen 60/70 is mainly binder material in Indonesia, it is used as the default for all samples in this experiment. The optimum bitumen content (OBC) was determined for all the mix by Marshall mix design. In view of the nanomaterial approach, samples were then prepared for the same optimum bitumen content (5.85%) by using Bina-Marga’s PA standard in control mix as well as natural FA and treated FA as alternative filler in modified mixes. Treated FA itself has been milled using transversal ball mill machine for 3 to 6 hours. Experimental results indicated higher stability value and reduction of permeability with the same OBC for the mixture having treated FA as filler content in comparison with standard mix and natural FA mix. It is proposed that additional finer material of treated Fly ash as alternative filler added into asphalt mixture resulted in improvement strength. In order to do that, the required amount of treated Fly ash should be less than 200 grams.

The Effect of Fly Ash and Recycled Aggregate on the Strength and Carbon Emission Impact of FRCCs

Concrete is the most widely used construction material in the world. In particular, cementitious composites that contain reinforced fibers have a relatively large amount of cement. Therefore, in this study, the target is to maintain at least 90% of the performance along with a reduction of CO2 emissions from the material stage during fiber-reinforced cementitious composites (FRCCs) production by applying fly ash (FA) and recycled sand (RS). To calculate the amount of CO2 emission at the stage of manufacturing the FRCCs, life cycle inventory database (LCI DB) were referenced from domestic and Japan. As the performance efficiency indicators, simple equations to evaluate the amount of CO2 emission of FRCCs were then formulated as a function of the replacement ratio of FA and RS. And binder and CO2 intensities were analyzed by FRCCs strength. Based on the results for the test, a mix of FA 25% and RS 25% of W/B 0.45, is considered most suitable in terms of performance of FRCCs and reduction of CO2 emissions.

A study on the potential of geopolymer artificial aggregate as substitute for granite and limestone aggregate

The aim of this research is to determine the potential of geopolymer artificial aggregate as substitute for granite and limestone aggregates. Several aggregate property test such as aggregate impact test, aggregate crushing test, specific gravity test, water absorption test and the Los Angeles Abrasion test are done on the aggregates. The fly ash-based geopolymer artificial aggregate is produced through geopolymerisation by mixing fly ash with alkaline solution. The results show that the fly ash-based geopolymer artificial aggregate is lighter than natural aggregate in term of its specific gravity. The impact value and crushing value for fly ash-based geopolymer artificial aggregate are slightly higher compared to natural aggregate while the water absorption value is much higher compared to natural aggregate. Furthermore, the fly ash-based geopolymer artificial aggregate has higher value in the Los Angeles Abrasion. Overall, the fly ash-based geopolymer artificial aggregate can be considered as one of the construction materials in the roadwork pavement and in concrete as an alternative for coarse aggregate besides natural aggregate with more lightweight properties.

Analysis of thermal power plant fly ash and lime in increasing shear strength of soft clay

Soil is the basic foundation for any civil engineering structures. It is required to bear the loads without failure. In some places, soils are weak which cannot resist the oncoming loads. Soft clay is known to have low strength and high compressibility. Utilization of additive is a method that can be applied to increase shear strength of soft clay. This study was conducted to determine the effectiveness of mixing fly ash, lime and soft clay with different percentage in order to increase the strength. A series of laboratory test were conducted in determining the physical properties, compaction and shear strength on soft clay soil. The soil samples; both disturbed and undisturbed were obtained from the vicinity of Politeknik Sultan Idris Shah (PSIS). Two tests carried out are compaction and direct shear strength. From the results, the highest strength of soft clay was at 69 kPa by mixing soil with 12% fly ash + 4% lime.

Preparation and Photocatalytic Properties of Ceramic Nanocomposites Added Zinc Sulfide Nanoparticles

We fabricated ceramic ZnS nanocomposites by mixing fly ash of a thermal power plant and waste glass powder with ZnS nanoparticles manufactured by a template-free hydrothermal treatment method. Ceramic ZnS nanocomposites with structure and mechanical properties produced using powder mixtures were obtained by applying milling and annealing procedures at a heat treatment temperature of 700 °C. Its photocatalytic activity was evaluated with methyl orange (MO), acetaldehyde (ATA), 2,4-dichlorophenoxyacetic acid (2,4-D), and methylene blue (MB) as photodegradation targets. Crystallization behavior of ceramic ZnS nanocomposites prepared in this study was examined through X-ray diffraction (XRD) analysis and surface morphological observation. Chemical composition of the ceramic ZnS nanocomposites was estimated using field emission-scanning electron microscopy (FE-SEM) and energy dispersive X-ray spectrometry (EDS). Its physicochemical properties were characterized by measuring density, compressive strength, bending strength, and chemical durability according to ZnS nanoparticle content. Results confirmed that addition of ZnS nanoparticles significantly improved physicochemical properties of the prepared nanocomposite samples. As the content of ZnS nanoparticles increased, photocatalytic activity of ceramic ZnS nanocomposites with and without acid treatment for photodegradation target material also increased under UV light irradiation. Degrees of photocatalytic degradation of MO, ATA, 2,4-D, and MB by ceramic ZnS nanocomposites added with 20 wt% ZnS nanoparticles (after immersion in acidic solution) were about 0.285, 0.118, 0.280, 0.256 after UV irradiation for 180 min, respectively. Moreover, the photocatalytic degradation rate of target substances for photodegradation was estimated using pseudo-first-order kinetics proposed by Lagergren.

Experimental Study on the Effects of Fly Ash on Sand Fixation with Microbial Induced Carbonate Precipitation

In order to study the sand-fixing effect of microbe induced mineralization after mixing fly ash with eolian sand, different samples of eolian sand were treated. The effects of blending fly ash on microbially induced mineralization and sand fixation were evaluated based on the comparison of permeability, water retention, surface strength, and wind erosion resistance. After three times of microbial induced mineralization treatment with 30% fly ash contained, it showed:(1)the permeability coefficient decreased by 79.4%;(2) the cumulative evaporation decreased by 26.5%;(3)the surface strength increased by 19.9%;(4)and the wind erosion rate decreased by 21.2%. The yield of calcium carbonate was negatively correlated with the wind erosion rate and positively correlated with the surface strength. From the experiment, it can be concluded that mixing fly ash is more practical than simply using microbial induced mineralization to fix sand, which can significantly reduce the permeability, improve the water retention performance, improve the surface strength and wind erosion resistance of the solidified layer of aeolian sand.

Effectiveness of Expanded Polystyrene (EPS) Beads Size on Fly Ash Properties

The present study focused on laboratory investigation of fly ash mixed with expanded polystyrene (EPS) beads. Different sizes of EPS beads were mixed with fly ash to study the effect on maximum dry unit weight, cohesion, angle of internal friction, California bearing ratio (CBR) value, coefficient of consolidation, and permeability. The different EPS beads sizes used in the present study are 1 mm, 2 mm, 3 mm, 4 mm, and 6 mm with 28 kg/m3, 19 kg/m3, 16 kg/m3, 11 kg/m3 and 6 kg/m3 densities, respectively. The effects of EPS beads sizes on geotechnical properties of fly ash mixture were investigated. The constant EPS beads content of 0.6% was considered for comparing the effect of different sizes of EPS beads in the fly ash. The smaller EPS beads–fly ash mix was observed to be suitable for improving the shear strength and bigger EPS beads were good enough to reduce the unit weight of fly ash–beads mix. The CBR value and permeability of fly ash–EPS beads mixtures were increased with a decrease in the size of EPS beads. The coefficient of consolidation increased up to 4-mm size of beads and then decreased for 6-mm size of beads. The fly ash reinforced with 0.6% EPS beads of different sizes, specifically 1-mm and 2-mm size, can be useful for constructions on weak soils. Each size of EPS beads has benefits as per the requirements in engineering applications and field conditions.

Hardened Behavior of Fly Ash Incorporated Concrete with Bottom Ash (FACB) as Partial Replacement of Fine Aggregate

The utilization of thermal power plant waste ashes (fly ash and bottom ash) in concrete as partial replacement of cement and sand could be an important step toward development of sustainable, user-friendly and economical infrastructure. For this purpose, different concrete mixes were considered at constant binder content of 300kg/m3 and differ water-to-binder ratio (w / (c + f) mainly as 0.5 , 0.55 and 0.6. Also six wide range of fly ash replacement levels (f/c ratio) namely 0, 0.11, 0.25, 0.43, 0.67 and 1.0 were introduced in the experimental scheme. The 3-days to 180 days compressive strengths of FACB was measured at interval of 3, 7, 28, 56 and 90 days. This study also presents a relationship between the ratios of split tensile (ft) strength to compressive strength (fc). It is applicable to lean concrete having consideration of curing period at early age (3day) to long term (180days). The results of this investigation are principally important, because the comprehensive information on the dependability of the relationships has not been available for (w/c+f) and bottom ash combination. The investigational results of this work are indicated that waste-Bottom ash with the regular sizes can be used successfully as a fine aggregate in fly ash concrete (FAC). The Study also reflected in finding constant “k” by ACI code equation for fly ash and bottom ash mix concrete. It has obtained between 0.337 - 0.504. This could be useful in finding splitting tensile strength when concrete carrying fly ash and bottom ash.

Seawater Exposure Effect on Fly Ash based Geopolymer Concrete with Inclusion of Steel Fiber

Concrete is widely used in construction offshore such as concrete floating bridges and sea tank. This research is providing an alternative construction material to replace ordinary Portland cement (OPC) concrete known as geopolymer. The geopolymer concrete was produced by mixing fly ash with alkaline activator and 3% of steel fibre in order to improve the properties of fiber reinforced geopolymer concrete (FRGPC). The effects of aging period in term of strength, changes in weight and carbonation of FRGPC in seawater is investigated and compared with the fiber reinforced concrete (FROPC). The compressive strength obtained for FRGPC were higher than FROPC. The highest compressive strength obtained by FRGPC is 76.87 MPa at 28 days and 45.63 MPa at 28 days for FROPC concrete. The compressive strength was decreased as the period of immersing the concrete in seawater is increased. During the immersion process of both samples in seawater up to 120 days, the carbonation was not detected even though with the existence of steel fibres.

Experiments on Foamed Concrete for the Development of Building Blocks

Foamed concrete is an innovative and versatile lightweight building material, which is a cement-based mortar consisting of at least 20% of its volume filled with air. Use of lightweight foamed concrete blocks with densities less than 1800 kg/m3 as infills will lead to the design of slender sections. Further, the thermal insulation properties of foamed concrete blocks made it more popular in construction industry. This paper discusses the development of foamed concrete building blocks for load bearing and non-load bearing structures. To make the mix more sustainable, the feasibility of fly ash as a partial replacement to cement is also explored. The variables considered for the production of foamed concrete are foam volume, water/powder (mix of cement and fly ash) ratio, fly ash content and sand/powder ratio. Analytical model is also developed for compressive strength and dry density of foamed concrete considering different variables and it is validated. Compressive strength is found to be increasing with the increase in dry density and with increase in fly ash content. Thermal conductivity is observed to be reduced by the addition of fly ash content.

EFFECT OF FLY ASH ON GEOTECHNICAL PROPERTIES OF SOIL

This paper investigates the effect of fly ash (generated from thermal power plant, Panki, Kanpur) on geotechnical properties of local soil, Bhauti Kanpur (U.P), INDIA. The fly ash used in the experimental work was of Class ‘F’ and soil was clayey in nature .Fly ash collected from the hopper attached to an electrostatic precipitator when coal was changed at a coal fired power plant. Concerning the major challenges regarding the safe reuse, management and disposal of these wastes an attempt has been made to mix fly ash at 5,10, 15, 20, 25, and 30% on the basis of dry weight with local clay soil. To understand the behavior of fly ash with soil, numbers of laboratory experiments were performed on the local soil (clay) and contaminated soil with varying percentage of fly ash. As the result, it is shown that all the investigated properties were decreased except CBR value and optimum moisture content.

STRENGTH ASPECTS OF FLY ASH IN CEMENT MORTAR

The aim of the investigation was to evaluate the feasibility of mixing fly ash in cement to make mortar specimens for getting an agreeable compressive Strength of the mortar. Different proportions of cement and fly ash were tried at laboratory-scale, utilizing dry fly ash at 15%, 20%, 25%, 30%, 35%, 40%, 45% and 50% of cement weight. The reference mortar was prepared with 100% of Ordinary Portland Cement (OPC). The blended mortar was utilized to make standard cubes of uniform size, namely, 70.6mm (L), 70.6 mm (W) and 70.6 mm (H). After curing at standard temperature and humidity, being soaked in potable water, tests were carried out, for evaluating the compressive strengths attained by the cube specimens, at the curing ages of 3, 7, 14, 21 and 28 days. The 28th day’s compressive strength of the cement-fly-ash-mortar containing 70% cement and 30 % fly ash was 37.53N/sq.mm, which corresponded to 93.7% of the Compressive strength(40.06N/sq.mm) attained by the reference mortar which contained 100.0 % of cement. and zero percent. It was inferred that fly ash can be added at 30% weight of cement in the mortar, on dry weight basis.

Effect of crystalline admixture, fly ash, and PVA fiber on self-healing capacity of concrete

The ability of concrete admixtures to self-heal is an important way to improve concrete durability. The influence of crystalline admixture (CA), fly ash (FA) and PVA fiber on the self-healing capacity of early-age cracks in concrete was studied. The compressive strength recovery, electrical resistivity recovery, and morphology of crack surfaces were used to evaluate of early-age cracking in concrete. In this research four mixes are cast, control mix (M1), 0.1% of PVA fiber by volume mix (M2), 20% partial replacement of cement with fly ash mix (M3) and 2% of CA by mass of cement mix (M4). The cracks were formed by applying the compressive load for early-age cracks after 3 days of curing. Self-healing products are studied using scanning electron microscopy (SEM). It was observed that all admixtures show self-healing capacity to some extent. The results showed that the recovery of compressive strength and electrical resistivity of the cracked CA concrete samples has the highest self-healing capability due to the presence of calcium carbonate and C-S-H gel which were confirmed by SEM analysis.

Rheological and strength properties of self-compacting concrete incorporating marble and granite powders

The use of waste products like fly ash in self-compacting concrete (SCC) is a common practice. In regions where a lot of waste generated due to sawing and polishing of granite and marble has a huge potential of using them in concrete without compromising the rheology and strength. This paper presents the experimental investigations on rheological behavior (T500, Vft, and viscosity) and strength properties (compressive, flexural, and splitting tensile strengths) of SCC made of marble and granite powders. The comparison was made with higher fly ash and higher sand content concrete mixes. The rheological properties showed similar and linear inter-relationship between different sets of mixes. Most of the mixes fall under VS2/VF1 and VS2/VF2 categories of EFNARC specifications. The strength properties of SCC mixes were compared with normal concrete mixes and found analogues with control concrete mix. The use of marble and granite powders up to 360 kg/m3 was studied. There is a beneficial effect due to the reduction of other raw materials significantly in concrete mixes. The admixture dosage was identified and found to be dependent on the surface area of particles.

The processing, properties and optimum mix of fly ash based - self compacting geopolymer concrete

The development of concrete technology toward environmentally friendly concrete has become increasingly interest area. The production of Portland cement has a significant impact on greenhouse emissions. The fact triggers the research and the development of eco-friendly concrete, one of which is geopolymer concrete. The implementation of concrete casting sometimes faces the construction that requires the casting process without vibration. It is then when the self-compacting concrete technology was developed. Concerning the two main issues of eco-friendly self-compacting concrete mention above, fly ash based-self compacting Geopolymer concrete has become a research study and develops in the last decades. This paper identifies the process, properties, an optimum mix of fly ash-based self-compacting geopolymer concrete. The properties in this research are the workability of fresh concrete and compressive strength at 7 days. Compressive strength is reported with several NaOH molarities, Alkaline to fly ash ratio, curing time, Curing temperature, Superplasticizer, and Extra Water. Examination of the workability is done with a slump flow test, V-Funnel test, and L-Shape box test. The result shows the optimum mix of fly ash based self-compacting geopolymer concrete.