Partial Replacement Of Fly Ash Research Articles

Effect of Partial Replacement of Fly Ash by Decoration Waste Powder on the Fresh and Mechanical Properties of Geopolymer Masonry Mortar

Effect of Partial Replacement of Fly Ash by Decoration Waste Powder on the Fresh and Mechanical Properties of Geopolymer Masonry Mortar

Laboratory Studies on Strength Properties of Concrete using Fly Ash and GGBS

Abstract: Cement, fine aggregate, coarse aggregate, and water are the basic raw materials used in the manufacture of concrete. The naturally available aggregates are very precious and need to be conserved. Waste materials such as fly ash and Ground Granulated Blast Furnace Slag (GGBS) which cause disposal problems, and environmental problems can be economically used as a partial replacement for both fine and coarse aggregate. The present research focuses on conducting laboratory studies on the properties of M30 grade concrete by replacing fine and coarse aggregate with fly ash and GGBS. The results show that the optimum percentage of partial replacement of fly ash and GGBS is 30% for both fine and coarse aggregate. The compressive strength of concrete increased by 15% and 24%, respectively, and the tensile strength of concrete nearly increased by 20% in both cases. In addition, the use of waste material helps to reduce the cost of construction while simultaneously solving the disposal and environmental pollution problems.

Effect of Mechanical Properties of Concrete Using Nano Titanium Dioxide and Partial Replacement of Fly Ash in Cementitious Material

Effect of Mechanical Properties of Concrete Using Nano Titanium Dioxide and Partial Replacement of Fly Ash in Cementitious Material

Effect of Mechanical Properties of Concrete using Nano Silica and Partial Replacement of Fly Ash in Cementitious Material

Effect of Mechanical Properties of Concrete using Nano Silica and Partial Replacement of Fly Ash in Cementitious Material

Investigation on enhancing the mechanical properties of Alkali-Activated concrete based on fly ash with wollastonite

Alkali-activated concrete (AAC) is one of the cement-free concretes. It has attracted attention as a notable alternative to conventional Portland Cement Concrete (PCC) due to its superior mechanical properties and environmental benefits. This study investigates the impact of wollastonite, an industrial mineral composed chemically of calcium, silicon, and oxygen, on the mechanical properties of fly ash-based AAC. The compressive strength, split tensile strength and flexure strength at the different liquid-to-binder ratios (such as 0.35, 0.40 and 0.45) are examined. The partial replacement of fly ash with mineral wollastonite powder was carried out at different percentages varying from 5% up to 30%. Samples are cured using both oven curing and ambient curing procedures, and the test results are obtained. In the observation, the best test results are obtained at 20% replacement of fly ash with wollastonite irrespective of liquid-to-binder ratio values. Hence, the AAC with a composition of 20% wollastonite and 80% fly ash has been recognized to have optimum mechanical properties. The findings of this study would largely help to achieve the goals of “zero-waste” production.

Workability Assessment of Pumpable Structural-Grade Heavy-Weight Concrete Using Novel Coaxial Cylinder Method

The mixture proportioning of heavy-weight concrete (HWC), as seen from the literature, is primarily based on a trial-and-error approach; even so, data from the literature indicate that obtaining high-slump mixtures for high density levels (more than 3.1 g/cm3) is difficult. Because heavy-density aggregates are prone to segregation at high slump, a low water to cement ratio is generally used for HWCs, and full-scale pumping trials are needed for checking pumping placement. For structural-grade HWCs used in nuclear facilities and specific infrastructure such as tunnel cross-rail floating slabs, rheological properties are needed to quantify the workability for pumping placement. Because use of rheological assessment methods using sophisticated rheometers cannot be realized easily onsite, a novel coaxial cylinder method is proposed in this study for determining the yield stress of HWCs delivering 3,800 to 3,900 kg/m3 density. The device proposed in this study is portable and can be used also onsite. Four structural-grade hematite aggregate HWCs, with design strengths varying from 40 to 70 MPa, were designed with ordinary portland cement. To understand the effect of fly ash addition on rheological behavior, one of the structural-grade HWC with three different levels (15%, 25%, and 35%) of fly ash was investigated. For referring the initial workability and workability retention properties of HWCs used in jobsite pumping, the conventional slump test values of the mixture were compared with yield stress measurements. Experimental investigations suggested that the method proposed in this study are able to adequately capture the workability characteristics required for pumpable mixtures. Further, it was seen that 35% partial replacement of fly ash resulted in 100% reduction in yield stress of HWC mixtures. Fly ash replacement (15% to 35%) did not significantly alter the hardened concrete density (3,800 kg/m3); however, attainment of the specified compressive strength depended on the replacement level of fly ash and extended curing period.

Effect of Bamboo Leaf Ash on The Properties of Geopolymer Concrete at Ambient Curing Temperature

As a result of the growing environmental concerns in the cement industry and the rising cost of building materials, alternative cement technologies have become an area of increasing interest. In this study, geopolymer concrete containing fly ash class F and bamboo leaf ash was chosen as a cement substitute in concrete manufacturing. This research was an experimental study evaluating the effect of bamboo leaf ash (BLA) on geopolymer concrete by addition as a partial replacement of fly ash. The test samples were 100 x 100 x 100 mm cubes and 300 x 150 mm cylinders at the ambient curing temperature. The design mix of C25 was used for this study. This research aimed to explore the suitability of the use of bamboo leaf ash as a mixing material in geopolymer concrete in more environmentally friendly industries. The properties that were investigated in this study are the basic aggregate tests, XRF analyses of BLA and fly ash, and workability tests by evaluating slump and compaction factor tests. In addition, compressive strength and splitting tensile strength of 28, 56, and 90 days. Therefore, in this study, various levels of bamboo leaf ash were utilized, including 0%, 5%, 10%, 15%, and 20% BLA. The alkaline liquid-to-binder ratio for all mixes was constant at 0.6, while the Na2SiO3 to NaOH ratio was 2.5. The test results of the workability show that the increased amount of bamboo leaf ash gradually reduces the alkaline liquid. The result of compressive and splitting tensile showed that fly ash substitutes that contained 5% and 10% of the bamboo leaf had higher strengths of about 38.7 MPa, 40.8 MPa, 4 MPa, and 4.22 MPa, respectively than other mixtures. Therefore, bamboo leaf ash can be one of the constituent materials used to improve the mechanical properties of geopolymer concrete

The compressive strength and the setting time of partial replacement of fly ash by palm oil fuel ash on geopolymer paste and mortar

This study replaced fly ash with palm oil fuel ash (POFA) in geopolymer paste and mortar. The alkaline activator was a mixture of sodium silicate solution and sodium hydroxide solution with a ratio of 2.5. Three variables were evaluated: the raw material combination (100% fly ash and 25% POFA substituted to fly ash), the mass ratio of raw material to alkali activator (60/40, 65/35, and 70/30), and NaOH molarity (8 M and 10 M). The geopolymer mortar was utilized based on the highest compressive strength of geopolymer paste. The ratio of fine aggregate to binder was 65 to 35. The result showed that the compressive strength of geopolymer paste increased as NaOH molarity increased. 25% substitution of POFA for fly ash increased the compressive strength of geopolymer paste from 12.0% to 27% at 28 days. The raw material/ alkali activator ratio of 65/35 indicated the highest compressive strength. The POFA replacement for fly ash had a longer setting time than 100% fly ash. The compressive strength ratio of mortar to the geopolymer paste was 0.66 and 0.59 for the 65/35 and 70/30 ratios of raw material to alkali activator, respectively.

Estimation of strength, rheological parameters, and impact of raw constituents of alkali-activated mortar using machine learning and SHapely Additive exPlanations (SHAP)

One-part alkali-activated material (AAM) is a new eco-friendly developed low-carbon binder that utilizes alkaline activators in solid form. This study deals with the experimental synthesis of one-part alkali-activated mortar (AAM) based on the partial replacement of fly ash (FA) with hydraulic lime (LM) as a precursor, and machine learning-based gene expression modeling (GEP) modeling for the optimization of the developed AAM. The datasets were established by the experimental work performed during this current study. The chosen input parameters were fly ash, hydraulic lime, sodium silicate, sodium hydroxide, sand/binder, water/binder, curing age, and time after mixing. The experimental results showed greater compressive strength and rheological parameters for the specimens having a high quantity of hydraulic lime. The GEP model has shown a strong generalization capability and prediction capacity for the future estimation of compressive strength, plastic viscosity, and yield strength. All the models showed a strong correlation of 0.92, 0.89, and 0.96 for compressive strength, plastic viscosity, and yield stress respectively. SHapely Additive exPlanations (SHAP) were employed to explore the effect of each input parameter of AAM on the predicted outcomes. The results revealed a strong interaction and positive effect of LM on the YS and PV while a negative impact was observed for the compressive strength. While fly ash has shown a negative impact on three outcomes of PV, YS, and CS respectively. The addition of LM and SS-activator leads to earlier structural build-up due to the flocculation of particles caused by the faster geopolymerization reactions.

Physico-Mechanical and thermal behavior of prolong heat Cured geopolymer blocks

Geopolymer has played an important role in the development of environment friendly building material using waste from various industries, agriculture and municipal waste. Most of the waste obtained from various industries are pozzolanic in nature or can be made reactive upon processing. Thus, are easy to incorporate in the mix design to achieve desired physical and mechanical properties. However, in practical scenario the total cost of the building materials is controlled by incorporating non-reactive materials as fillers. Considering this, an experimental investigation is carried out to develop with an objective to develop thermally efficient geopolymer block containing a fixed amount of crusher dust as filler and fly ash as the primary precursor and either rice husk ash or bottom ash as partial replacement of fly ash (i.e., 20, 30 and 40 % of fly ash). A combination of sodium silicate and sodium hydroxide mixed in the ratio of 2.5 was used as the alkaline solution and are cured at a constant temperature of 60 °C. The obtained results show that the developed geopolymer has lower thermal conductivity as compared to the traditional bricks and has lower water absorption and porosity values. The compressive and flexural strength are found to be greater than the strength requirement of first-class bricks.

Experimental and microstructural analysis on flyash-GGBS based geopolymer concrete under ambient curing condition

The large-scale production of cement is posing environmental problems on one hand and unrestricted depletion of natural resources on the other hand. Each ton of Portland cement production results in loading about one ton of CO2 in to the environment. Environmental and economic reasons require there vision of present concrete making materials. Fortunately within this scenario a new player has emerged that can help in mitigating the problem and the player is Geopolymer Concrete. Hence, the present research work is focused on pozzolanic materials by replacing ordinary Portland cement (OPC) content in the concrete. The pozzolanic materials selected are in the form of geopolymer concrete (GPC) which utilizes waste materials like fly ash, ground granulated blast furnace slag (GGBS), silica fume, etc. Most of the researchers did significant amount of research on fly ash based GPC with heat curing methods. The parameters influencing compressive strength of GPC are total combined aggregate, alkaline to binder ratio, replacement of fly ash with GGBS, mass of sodium silicate to sodium hydroxide, molarity of sodium hydroxide and curing conditions. A total number of 24 cubes of size 150 mm × 150 mm × 150 mm with 14 molarity are prepared, combined total aggregate as 70%, alkaline to binder ratio as 0.30, partial replacement of fly ash with GGBS as 40%, mass of Na2SiO3 to NaOH is 2.5 and admixture as 1.75% mass of binder. The specimens are kept for ambient curing for required days. The mechanical properties are compressive strength test, flexural strength test and split tensile test and the results are 53.10 N/mm2, 4.73 N/mm2 and 4.13 N/mm2 respectively and done the tests on durability properties like absorption, the results is %water absorption 2.865 and the level “Excellent” and done for Sulphate test also. In this research investigation is carried out the mechanical and durability studies and also examine the microstructural behaviour of geopolymer concrete using scanning electron microscope (SEM), energy dispersive X-ray spectroscopy (EDS) and X-ray diffraction (XRD). The existence of geopolymer structure due to the Ca with Ca/Si, Si with Si/Al ratios of 0.63 and 2.4 and the Si/Al ratio (2.4) is greater than the 1.65 indicates the presence of geopolymer products in the composition.

Effect of nano titanium di oxide on mechanical properties of fly ash and ground granulated blast furnace slag based geopolymer concrete

In current scenario, new innovative recyclable materials are scientifically tried to be a part of concrete for improving the properties and reducing the cost. The aim of the present study, is to evaluate the mechanical properties of Fly ash Ground Granular Blast Furnace Slag based Geopolymer Concrete (FGGPC), with partial replacement of fly ash by various percentage of Titanium di oxide (TiO2). In this study, mechanical properties like strength (compressive and split tensile strength) and elasticity properties (modulus of elasticity and modulus of rupture) are assessed, which is basic requirement study for any type of concrete. It is found that, up-to 3% partial replacement of fly ash by TiO2 result in enhanced mechanical properties of FGGPC. Models based on mechanical properties of conventional concrete are available in literatures and standards. Dependency of these models are checked using statistical method and interval concepts. Reliability of the relationships between conventional and FGGPC is validated by Integral Absolute Error (IAE), Mean Absolute Error (MAE), Root Mean Square Error (RMSE), prediction and confidence intervals concepts.

Ceramic Waste Powder as a Partial Substitute of Fly Ash for Geopolymer Concrete Cured at Ambient Temperature

The growth of the construction industry has expanded the demand for ceramic building products such as ceramic tiles, which constitute essential building materials. Nonetheless, a huge quantity of waste powder is produced during the polishing of ceramic tiles. The disposal of ceramic waste powder is a key environmental concern that needs to be properly addressed. The purpose of this research is to evaluate the potential of recycling ceramic waste powder as a geopolymer binder. The main objective consists of exploring the impacts of two types of ceramic waste powder (vitrified tiles and wall tiles) on the partial substitution of fly ash in geopolymer concrete. For this, concrete was prepared under ambient conditions without oven curing. Slump, compressive strength, split tensile strength, and modulus of elasticity tests were performed to measure the workability and the mechanical properties of the geopolymer concrete. Its durability was evaluated through water absorption and sorptivity tests. The microstructural behavior was investigated using scanning electron microscopy and X-ray diffraction measurements. The investigation revealed that a 15% partial replacement of fly ash by wall-tile ceramic waste powder in geopolymer concrete gave similar compressive strength, a 3% increase in tensile strength, and a 7% improvement in the modulus of elasticity. Partial replacement of fly ash with 15% vitrified ceramic waste powder reduced sorptivity and improved the microstructure of geopolymer concrete. The findings revealed that ceramic waste powder can be used to replace 10–15% of the fly ash in M35 grade structural geopolymer concrete, which can be cured under ambient conditions. Doi: 10.28991/CEJ-2022-08-07-05 Full Text: PDF

The influence of ZSM-5 waste on the properties of fly ash-based foamed geopolymer

ZSM-5 (Zeolite Socony Mobil-5) waste is generated by the deactivation of ZSM-5 due to the repeated cycles. Because of its strong ability to foam, the high quality siliceous feedstock ZSM-5 waste can be applied in geopolymer materials for geopolymerization. This paper investigated the influence of ZSM-5 waste on the microstructure, mechanical properties, and foaming mechanism of fly ash (FA)-based foamed geopolymer with microporesd. Sodium silicate solution with a modulus of 1.4 was used to prepare the geopolymer pastes with different contents of ZSM-5 waste, which were analyzed after being cured for 7 days. Results show that partial replacement of fly ash with ZSM-5 waste in FA-based geopolymer contributed to a porous structure with micropores. The optimal mixture was at the addition of 40% ZSM-5 waste, and the corresponding bulk density and compressive strength were 601.5 g/cm3 and 6.2 MPa, respectively. This paper can be used as a guide for the application of ZSM-5 waste in the geopolymer.

Durability and Microstructure Characteristics of Concrete with Supplementary Cementitious Materials

Considering the environmental impact of cement manufacturing industries, this paper concerns the potential of using supplementary cementitious materials (SCMs), like fly ash and ground granulated blast furnace slag, as being essential to replacing the existing Ordinary Portland Cement (OPC). The objective of this paper is to study the microstructural characteristics of concrete with SCMs and improve the durability of the product to increase the lifespan of concrete structures. Replacement SCMs in OPC are 0, 40, 50, and 60 by percentage of cement weight, and we have taken a water-binder ratio of 0.40 for M40 grade and 0.28 for M60 grade concrete. The physical properties and chemical composition of OPC, Ground Granulated Blast-furnace Slag (GGBS), and fly ash were identified, and three different experiments were conducted to determine the resistance to penetration of chloride ions and corrosion processes. The rapid chloride permeability test, accelerated corrosion, and sorptivity tests were employed to measure concrete's resistance to the effects of aggressive environments and examine the durability properties. The most performed grade samples were analyzed as individual microspheres with Scanning Electron Microscopy (SEM), Energy Dispersive X-Ray Spectroscopy (EDXS), and X-ray diffraction. Significant improvements in various concrete properties were achieved through the partial replacement of fly ash and GGBS with cement. Doi: 10.28991/CEJ-2022-08-04-05 Full Text: PDF

Environmental and Biological Impact of Fly Ash and Metakaolin-Based Alkali-Activated Foams Obtained at 70°C and Fired at 1,000°C

Alkali-activated foams (AAFs) are inorganic porous materials that can be obtained at temperatures well below 100°C with the use of inorganic wastes as aluminosilicate precursors. In this case, fly ash derived from a Slovenian power plant has been investigated. Despite the environmental benefits per se, due to saving of energy and virgin materials, when using waste materials, it is of extreme importance to also evaluate the potential leaching of heavy metal cations from the alkali-activated foams. This article presents an environmental study of a porous geopolymer derived from this particular fly ash, with respect to the leachability of potentially hazardous elements, its environmental toxicity as determined by biological testing, and the environmental impact of its production. In particular, attention was focused to investigate whether or not 1,000°C-fired alkali-activated fly ash and metakaolin-based foams, cured at 70°C, are environmentally friendlier options compared to unfired ones, and attempts to explain the rationale of the results were done. Eventually, the firing process at 1,000°C, apart from improving technical performance, could reinforce heavy metal cation entrapment within the aluminosilicate matrix. Since technical performance was also modified by addition of different types of activators (K-based or Na-based), as well as by partial replacement of fly ash with metakaolin, a life cycle assessment (LCA) analysis was performed to quantify the effect of these additions and processes (curing at 70°C and firing at 1,000°C) in terms of global warming potential. Selected samples were also evaluated in terms of leaching of potentially deleterious elements as well as for the immobilization effect of firing. The leaching test indicated that none of the alkali-activated material is classified as hazardous, not even the as-received fly ash as component of new AAF. All of the alkali-activated foams do meet the requirements for an inertness. The highest impact on bacterial colonies was found in samples that did not undergo firing procedures, i.e., those that were cured at 70°C, which induced the reduction of bacterial Enterococcus faecalis viability. The second family of bacteria tested, Escherichia coli, appeared more resistant to the alkaline environment (pH = 10–12) generated by the unfired AAMs. Cell viability recorded the lowest value for unfired alkali-activated materials produced from fly ash and K-based activators. Its reticulation is only partial, with the leachate solution appearing to be characterized with the most alkaline pH and with the highest ionic conductivity, i.e., highest number of soluble ions. By LCA, it has been shown that 1) changing K-based activators to Na-based activators increases environmental impact of the alkali-activated foams by 1%–4% in terms of most of the impact categories (taking into account the production stage). However, in terms of impact on abiotic depletion of elements and impact on ozone layer depletion, the increase is relatively more significant (11% and 18%, respectively); 2) replacing some parts of fly ash with metakaolin also results in relatively higher environmental footprint (increase of around 1%–4%, while the impact on abiotic depletion of elements increases by 14%); and finally, 3) firing at 1,000°C contributes significantly to the environmental footprint of alkali-activated foams. In such a case, the footprint increases by around one third, compared to the footprint of alkali-activated foams produced at 70°C. A combination of LCA and leaching/toxicity behavior analysis presents relevant combinations, which can provide information about long-term environmental impact of newly developed waste-based materials.

Influence of iron tailing powder on properties of concrete with fly ash

The influences of iron tailing powder (ITP) on slump, compressive strength, drying shrinkage, carbonation resistance, chloride permeability, frost resistance and sulfate attack of concrete with fly ash were investigated. The incorporation of ITP enhances cohesiveness of concrete with small loss of slump. Partial replacement of fly ash with ITP increases early-age compressive strength but decreases later-age compressive strength of concrete. Increasing ITP content has little effect on early-age drying shrinkage but decreases total shrinkage within 180 days. The carbonation resistance is improved and the good frost resistance of concrete is obtained by adding ITP. The chloride permeability grade of concrete cannot be affected when the proportion of ITP replacing fly ash does not exceed 50%. The best resistance to sulfate attack is obtained when 50% fly ash is replaced by ITP. Decreasing water/binder ratio is advantageous to improving mechanical properties and durability of concrete containing fly ash and ITP.

3D printability of ternary Portland cement mixes containing fly ash and limestone

This paper reports the influence of limestone, by partial replacement of fly ash, on the fresh properties, printability, and interlayer bond strength of 3D printed high volume fly ash mortar. Limestone powders at replacement levels between 0 and 15% (mass basis) were used to proportion ternary binder formulations. The incorporation of limestone alters fresh properties like slump, slump flow, yield stress. It was observed from the results of 3D printing test that ternary mixes with limestone demonstrates higher buildability. Based on the material relative deformation at different times and concurrent printing, the effect of mix designwas linked to the printing performance. The results of interlayer bond strength revealed that bond strength decreases with increase in limestone dosage. It was observed that the bond strength for the high buildable mix in the bottom layers was lower followed by middle and top layers. This is due to an overestimation of bond strength caused by X-directional porosity (i.e. printing direction) resulting from increased nozzle standoff distance induced by bottom layer suppression.

Bond strength of autoclaved aerated concrete manufactured using partial replacement of flyash with fibers – A review

Autoclaved aerated concrete is widely attracted because of its excellent environmentally friendly characteristics and thermal insulation property. Autoclaved lightweight concrete (ALC), autoclaved cellular concrete (ACC), cellular concrete, autoclaved concrete, porous concrete, Ytong, hebel block, aircrete, and thermalite are some of the other names for AAC. AAC is a cent percent green construction material that has been used to construct the highest rated green structure. It consumes the least amount of energy and material per cubic meter of product, making it the most energy and resource efficient. Unlike brick manufacturing, which wastes valuable agricultural soil, AAC uses fly ash as the most beneficial answer to the country's fly-ash use problem. AAC's unrivalled strength-to-weight ratio, which is even higher than M150 concrete and greatly exceeds Indian building code standards, is achieved by a high-pressure steam-curing autoclaving process. In this article physical, mechanical and microstructural properties of AAC on replacing fly ash with various additives are studied. Comparison of properties for AAC manufactured using different additives were made and explained. AAC is a versatile building material. Fiber reinforced aerated concrete (FRAC) is a form of light weight aerated concrete which consist of internal reinforcement with small polymer fibers. Numerous materials such as basalt, rice husk, granite, graphite, zeolite, municipal solid waste, iron ore tailings, silica fume were used as fibers and incorporated (especially organic and industrial wastes) in manufacturing process of AAC. The mechanical (drying shrinkage), physical (compressive strength, flexural strength, thermal insulation, modulus of elasticity) and microstructural analysis (XRD, SEM) were done for different fiber incorporated AAC and results were studied an d compared. Above study indicates that all the properties depend on main factors such as condition during autoclaving process. Thus by the use of autoclaving, various industrial wastes, industrial byproducts and organic wastes are used in manufacturing AAC leads to reduction in wastes and widening the application of AAC.

Effect of Limestone Powder on Mechanical Properties of Engineering Cementitious Composites

The effect of limestone powder replacing fly ash on the mechanical properties of engineering cementitious composites was investigated. The results showed that the water demand of engineering cementitious composites due to partial replacement of fly ash by limestone powder, but the water demand of the system decreased when the replacement ratio reached 100%. The flexural strength of the specimen appears to decrease with increasing age due to incomplete replacement of lime powder. The toughness of the specimen can be significantly improved due to the complete replacement of fly ash by limestone powder.