Percentage Of Fly Ash Research Articles

The effect of slag and fly ash content on the properties of electric furnace nickel slag-based geopolymer used for repair materials

Large quantities of electric furnace nickel slag (EFNS) are annually generated through the smelting of ferronickel in industries. EFNS contains a large amount of glass phase SiO2 and MgO, with certain volcanic ash activity. Nevertheless, the lower early activity of EFNS due to the ultra-low Ca and Al greatly limits its application. To descend the consumption of raw materials and mitigate environmental pollution, utilizing such wastes as a binding agent in the domain of repairing mortars is a suitable solution. To address the lack of Ca and Al and adjust the ratios of Ca/Al and Si/Al in EFNS-based mortars, the purpose of the research was to incorporate different contents of slag (SL) and fly ash (FA) from 25% to 40%, respectively, into EFNS-based mortars activated with Na2SiO3. The study involved an investigation of the workability, mechanical properties, bond strength, and dry shrinkage of the mortars, employing different percentages of SL and FA. At the same time, TGA, XRD, MIP, and SEM were applied to investigate the chemical composition and microstructure of the binder gel phase. The results showed that when the SL content reached 40% and the FA content was 30%, the repair performance of mortar was much better than numerous repair materials, with an excellent compressive strength (94.0 MPa), flexural strength (11.0 MPa), and bond strength (6.33 MPa). As such, increasing the SL and FA contents seemed to have a positive influence on dry shrinkage and mechanical strengths. Additionally, when the FA content was 30%, the incorporation of SL was found to promote EFNS hydrolysis, and the hydration could directly generate hydrotalcite, which was beneficial to decreasing drying shrinkage at 28 d. The present study provides a theoretical foundation for the application of EFNS-based geopolymers in repair materials.

A Study on Optimum Use of Fly Ash and GGBS in Fiber Cement Sheet to Enhance Sustainable Manufacturing

The biproducts of different industries must be reused or recycled which will avoid disposal of waste materials in the environment in different forms to protect our environment. Also the hazardous material used for the manufacturing of the products to be eliminated or minimized. In this paper a study has been conducted for optimum use of fly ash generated from power plants and Ground Granulated Blast Furnace Slag (GGBS) generated from steel plants in the manufacturing of fiber cemented roofing sheets. Also different percentages of fly ash, GGBS and pulp were added during the manufacturing of fiber cement roofing sheets in a fiber cement roofing sheet manufacturing plant and the quality of the final product has been tested subsequently in the laboratory to minimize the use of cement and asbestos fiber. Different results have been achieved in different percentages of fly ash, cement, GGBS, wood pulp and asbestos fiber combination. It is found that up to 36% addition of fly ash is acceptable with respect to the quality acceptance criteria of the final product, above 36% degrades the quality of the product which doesn’t meet the BIS: 459 standard requirements. Similarly, 10.38% of GGBS can be added without hampering the quality of the product. Finally, the best combination of raw mix design as per environmental sustainability point of view as well as the economic point of view has been suggested for the sustainable manufacturing of fiber cement roofing sheets.

Stress–Strain Model for Geopolymer Mortar under Active Confinement

A stress–strain model is developed for geopolymer mortar subjected to uniaxial compressive loading with active confinement. The model was developed using the triaxial test carried out on cylindrical geopolymer mortar samples cast with different weight percentages of slag and fly ash. The samples were tested under four levels of confining pressures (i.e., 0, 5, 10, and 15 MPa) to study the effect of confining pressure on peak stress, peak strain, volume change, modulus of elasticity, and Poisson’s ratio. The stress–strain behavioral model for geopolymer mortar together with the functional relationship for model parameters with confinement ratios is developed. The developed strain–strain model shows good agreement with the experimental results. Further, the modulus of elasticity and Poisson’s ratio are linearly varied with confining pressure. Also, the normalized volumetric strain factor increases linearly with the compressive strength. The obtained experimental results demonstrate significant improvement in strength and ductility due to confinement for geopolymer mortar.

A hybrid model based on convolution neural network and long short-term memory for qualitative assessment of permeable and porous concrete

Estimating design factors like concrete strength and durability is complicated by the cement industry's practice of producing multiple grades of cement for different uses, necessitating substantial labor hours and monetary investment. The experimental findings of accelerated carbonation-induced corrosion and associated durability characteristics of concrete built with high-volume Class F Fly Ash (FA), including AC impendence, half-cell potential, water permeability, and volume of permeable voids. FA was added to ordinary portland cement at varied replacement amounts (0–70%) to create concrete specimens. The concrete specimen has been prepared by varying different proportions of water cement ratio (0.45, 0.40, and 0.35). To predict the compressive strength and carbonation level of concrete, this study presents a simulation environment based on Artificial Intelligence (AI) that makes use of input parameters such as water/cement ratio, fly-ash percentage, and time duration. Here, One-Dimensional Convolution Neural Network based Long Short-Term Memory (1D-CNN-LSTM) has been proposed for estimating the carbonation depth and compressive strength of concrete. The developed model will be compared with other state-of-the-art techniques, including DL and ML-based techniques. The obtained R2 values from the proposed 1D-CNN-LSTM regression network deliver accuracy of 80% for estimating carbonation depth and 96% for predicting compressive strength. The proposed methodology demonstrates the use of modern AI-based techniques in the actual design model and illustrates the development of DL methods such as LSTM and CNN.

Sorptivity and rapid chloride ion penetration of self-compacting concrete using fly ash and copper slag

This paper represents experimental work on the mechanical and durability parameters of self-compacting concrete (SCC) with copper slag (CS) and fly ash (FA). In the first phase of the experiment, certain SCC mixes are prepared with six percentages of FA replacing the cement ranging from 5% to 30%. In the second phase, copper slag replaces fine aggregate at an interval of 20% to 100% by taking the optimum percentage value of FA. The performance of SCC mixes containing FA and copper slag is measured with fresh properties, compressive, split tensile and flexural strengths. SCC durability metrics, such as resistance against chloride and voids in the concrete matrix, is measured with rapid chloride ion penetration test (RCPT) and sorptivity techniques. The microstructure of the SCC is analyzed by using SEM and various phases available in the concrete matrix identified with XRD analysis. It is found that when replacing cement with 20% of FA and replacing fine aggregate with 40% of copper slag in SCC, higher mechanical strengths will be delivered. Resistance of chloride and voids in the concrete matrix reaches the optimum value at 40%; and with the increase of dosage, the quality of SCC will be improved. Therefore, it is recommended that copper slag be used as a sustainable material for replacement of fine aggregate.

Development and evaluation of coal mine waste materials for gainful utilization

Coal mine overburden and thick inseam parting materials found in the lower Gondwana basin are treated as mine wastes. Unused fly ash from coal-fired plants is another waste material. This investigation focused on using these wastes to develop better composite materials. Composite materials of varying compositions with coal mine wastes from 50 to 90% and fly ash from 10 to 50% with 2–6% cement additives were developed and evaluated. Their physical, chemical and geotechnical properties were determined. Ordinary Portland cement strongly influenced the geotechnical parameters. The fly ash content was optimized for unconfined compressive strength (UCS) and California bearing ratio for both mine wastes. Composite materials with 70% overburden, 30% fly ash and 6% cement showed a UCS of 4.01 MPa at 56 days. Composites with 80% inseam parting, 20% fly ash and 6% cement produced 4.90 MPa UCS at 56 days. Linear correlations were observed between fly ash percentage in the two composites and their UCS values. Pearson’s and Spearman’s coefficients produced a high correlation of −0.9 for the composite prepared with parting material. Microstructural analysis showed calcium silicate hydrate gel formation occurring at 28 days. The composites meet the strength criterion for the base and subbase of coal mine haul roads.

Shear strength behavior of organic soils treated with fly ash and fly ash-based geopolymer

Abstract Organic soil is a problematic soil that needs to be treated before construction because of the low shear strength and high compressibility. Using by-product materials, such as fly ash (FA), to improve soils is a cost-effective and sustainable procedure. Because treatment with FA may lead to reduce shear strength, a FA-based geopolymer was used with a cohesive organic soil to substitute the reduction in strength. A series of unconfined compressive strength tests (UCS) were conducted on compacted specimens treated with FA and geopolymer. The geopolymer was produced by adding sodium hydroxide to activate the FA. Different levels of FA content, curing period, and temperature were applied to the specimens. The results indicate that for the FA treated specimens, the UCS decreased as the FA increased. For the geopolymer-treated specimens, as FA percentage in the geopolymer increased, the UCS increased and the axial strain at failure decreased. The optimum content of FA, in the geopolymer, was 20%, and the highest UCS was achieved at a curing period of 28 days at a temperature level of 65°C. Based on the obtained results, FA-based geopolymer can effectively be used to improve the strength of organic soils.

Fracture properties of steel fibre reinforced high-volume fly ash self-compacting concrete

This paper presents an experimental investigation on the fracture mechanical properties of steel fibre-reinforced high-volume fly ash self-compacting concrete (HFSCC). Specifically, self-compacting concrete (SCC) of various toughness was designed at desired steel fibre volume fractions of 0, 0.25 v%, 0.50 v%, 0.75 v% and 1.00 v% by volume and fly ash contents of 40 wt%, 50 wt%, 60 wt% and 70 wt% by mass. The fracture mechanical properties of HFSCC (cured for one year) were studied by a three-point bending beam test. The influence of fly ash and steel fibre content on fracture parameters was systematically discussed. The research indicated that the fracture mechanical properties of HFSCC with different fly ash percentage were improved by adding steel fibres. The fullness of the force (F)-crack mouth opening displacement (CMOD) curves gradually increased with the steel fibre volume fraction (Vf). The peak load (Fp), peak CMOD (CMODP), fracture toughness (KIC) and fracture energy (GF) of the fracture parameters linearly increased with Vf. Furthermore, the correlation between them was analysed numerically. The slope of the fitting line increased with increasing fly ash content, indicating that high-volume fly ash was more conducive to improving the fracture mechanics of SCC after long-term ageing. After the hydration reaction, residual calcium hydroxide was observed only in the cross-sectional image of HFSCC-70, it helped to improve the fracture mechanical properties of HFSCC.

Durability Performance Analysis of Mixture Asphalt Concrete - Base Course (AC-Base) Using Coal Fly Ash as A Filler Substitute

Highways are land transportation infrastructure whose needs in Indonesia continue to increase, along with the increasing number of vehicle. The top Laston or base coarse (AC-Base) is a pavement foundation consisting of a mixture of asphalt aggregates with a certain ratio mixed and compacted in a hotmix. This coarse is at under binder coarse (AC-BC), not directly related to the weather, but it needs to have stability to withstand the traffic load spread through the vehicle wheels. Base coarse (AC-Base) serves to provide support the surface coarse, reduce strain and stress, spread and continue the load of road construction to the layer below (subgrade). Filler as one of the materials forming the AC-Base layer usually obtained from stone ash whose availability is increasingly difficult to feel in the field implementation. Therefore, a substitute material or substitute material is needed for the filler. One possible substitute material is fly ash. This research will analyze the performance of AC-Base coarse that make use of filler substitution material using fly ash with variation FA-0%, FA-5%, FA-7.5%, FA-10%, FA-12.5% and FA-15%. The samples made by Marshall Method will give the Optimum Asphalt Content (OAC) value on each mix variation. While the performance of this AC-Base mixture in increasing density, durability, and stability in the pavement mixture using the Marshall Immersion method (MI). The analysis result shows that the OAC value at 0% fly ash variation is 6,82%, at 5% fly ash variation is 6,87%, at 7.5% fly ash variation is 6,85%, at 10% fly ash variation is 6,84%, at 12.5% fly ash variation is 6,82%, and at 15% fly ash variation is 6.79%. While the performance of AC-Base mixture indicated by the MI value meets the specifications, and the MI value obtained tends to increase along with the increase in the percentage of fly ash. The mixture with 15% fly ash shows the better durability performance (99,75%) compared to other variations 0%, 5%, 7,5%, 10% and 12,5% (96,44%, 97,51%, 97,71%, 98,36% and 99,54%).

Response surface method for optimization of process variables for bioaccumulation of metals with Jatropha curcas on fly ash-amended soil.

Heavy metal contamination is a serious rising issue with the dumping of fly ash (FA). A recent focus of researches and practices tends towards reutilization of FA with bioremediation technique using various plants. The present research aimed to investigate optimum metal extraction in fly ash-amended soil using microbes and treated wastewater with Jatropha curcas plant using response surface methodology (RSM). The Box-Behnken design was used to determine the optimum condition for maximum metal remediation with three levels and three variables, viz., fly ash percentage (5, 12.5, 20%), microbial dose (0.5, 5.25, 10ml), and contaminant level of water to irrigate the plant (freshwater, treated wastewater, untreated wastewater). The approach adopted was to set fly ash percentage as "maximum," microbial dose as "minimum," and contaminant level of water to irrigate the plant as "in range." The outcome of the present research provided the best prediction models, integrated the process variables, and developed rotational curves for analyzing metal remediation in 360° rotation for Fe, Mn, Zn, Cu, and Al as responses of interest. The optimum conditions for maximum bioremediation from fly ash-amended soils by bioaccumulation on Jatropha curcas plant worked out as 13.866% fly ash, 4.088ml microbial dose, and treated wastewater as type of water to irrigate the plant that bioaccumulated Fe, Mn, Zn, Cu, and Al as to 26.904, 0.760, 0.160, 0.162, and 12.895mg/l.

Conservation of waste melon shell and fly ash utilized as reinforcements for aluminum alloy matrix in terrestrial ecosystem acquired green hybrid composites

AbstractNowadays, the environmental ecosystem is protected and maintains sustainability for waste material management like agriculture product end waste and industrial waste. The main scope of this research is to gather the agriculture end product of melon shell ash waste and industrial fly ash waste utilized as organic reinforcements for making a lightweight with superior strength green hybrid composite for fourth‐generation terrestrial ecosystem applications. The various volume percentage of waste melon shell ash and fly ash are governed by the ratio of 0:0, 1:4, 2:4, 3:4, and 4:4, respectively. The green aluminum alloy (Al6061) hybrid composite is synthesized via a semi‐solid stir technique. The developed green hybrid composites are subjected to physical and mechanical studies followed by ASTM standards. The developed composite contained a 4:4 ratio of melon and fly ash and found a light weight of 2.75 ± 0.11 g/cc with improved tensile strength and hardness percentages of 8.35% and 21.38% compared to cast aluminum alloy. This research may help basic knowledge for future investigations on modern green composite manufacturing via agricultural and industrial wastage.

Positive impact of polymer impregnated on the enhancement of the physico-mechanical characteristics and thermal resistance of high-volume fly-ash blended cement

To predict the enhanced performance and microstructure design of cement-based composites to achieve sustainability in construction, our study aims to investigate for the first time the positive impact of polymer impregnation on fire resistance and mechanical properties of cement-based composite pastes especially those with high percentages of high-volume fly ash (HVFA) at different water/cement ratios of 0.35, 0.40, and 0.45 and cured up to 90 days. These pastes were dried and impregnated with methyl methacrylate monomer and thermally treated at 70 °C for 3 h using 1% benzoyl peroxide as initiator. The effect of water/cement ratio, curing time, gel space ratio, and bulk density were investigated. Also, XRD, DTG/TGA analysis, and SEM are included. The compressive strength and polymer load were measured after the formation of impregnated- polymer pastes. The results indicated that reducing the w/c ratio leads to the production of hardened cement pastes with dense structures and relatively high compressive strength. For the polymer-impregnated samples, the values of compressive strength were decreased with increasing w/c ratio. The obtained data affirmed that the application of polymer impregnation within a cement matrix can be used to strengthen structures exposed to elevated temperatures. The impregnated cement pastes of ordinary Portland cement (mix OPC1) and blended cement OPC-FA pastes (mix OF1) with water/cement ratios of 0.35 showed higher compressive strength values when thermally treated up to 600 °C after 14 and 28 days of curing.

Sustainable high volume fly ash concrete with recycled C&D waste and dredged marine sand

Cement is a basic building material, and second largest building material used on earth. Huge production and use of cement has led to more CO2 being released into the atmosphere, worsening global warming and negatively affecting the environment. As a result, adopting a more sustainable strategy and carefully examining the current admixtures used to replace traditional concrete has become essential. In order to achieve the use of sustainable materials in construction, numerous studies have been done on replacing the cement with a maximum (50%) percentage of Fly Ash which has equivalent strength and better durability than traditional concrete. Very little literature has been reported on developing sustainable concrete mixers by replacing the course and fine aggregates using industrial waste materials. In this study, the M25 mixture design of High Volume Fly Ash (HVFA) Concrete is carried out with an optimum amount of Fly ash (50%) as cementitious material with OPC (50%). This mix percentage of the cementitious element is obtained after various trials and errors with 40, 50, and 60 percent of fly ash. Due to the pozzolanic characteristics of the fly ash and the lower w/cm ratios, the HVFA mixes achieved comparable greater long-term compressive strengths. In present investigation, coarse aggregate was replaced with recycled C&D waste (RCA) and fine aggregate with dredged marine sand (DMS) at its optimum percentage of 25% and 10%, respectively, to get the compressive strength of 30 MPa. This optimum percentage of Recycled C&D waste and dredged marine sand was obtained after conducting various trials and errors with each material, respectively. Evaluation of compressive strength test and flexural strength test determines the mechanical properties of HVFA concrete with RCA and DMS aggregate as replacement of coarse and fine aggregates.

Experimental investigation on self-curing concrete with sodium lignosulphate by partial replacement of cement with flyash

Concrete is a crucial and costly material in building construction. For good performance and durability of concrete, curing is essential. Huge quantities of water are needed for the curing of concrete. The self-curing technique can overcome this problem. Water is retained within self-curing concrete, allowing it to cure without additional moisture. In this study, we will utilize Sodium Ligno sulphate as a self-curing agent, and due to the tremendous demand for cement, its cost is increasing daily. Therefore, cement is partially replaced by fly ash (a waste product) to reduce costs. Self-Curing concrete using Sodium Ligno-sulphate is a substitute method for improving concrete's mechanical and physical properties. At 7, 14, and 28 days, tests for compressive, flexural, and split tensile strength are performed. The amount of fly ash used as a partial cement replacement ranges from 0% to 30%. This study aims to determine the optimal mix proportion for improved strength characteristics of concrete (M40) by fixing the Fly ash percentage at 20% and varying the Sodium Ligno sulphate percentage at 0%, 1%, and 2.5% by weight of cement.

Retention Behaviour of Heavy Metals from Industrial Sludge Amended with Admixtures to Use Them as Liners for Landfill Facilities

The solidification of contaminants within the soil/waste has proved to be a versatile technique to de-contaminate them and make them usable for several applications. In this method, the development of binder provisions leads to the conversion of the environmentally unstable condition of waste materials into a nearly stable material. Further, these materials pose a minimum threat that can be absorbed into the environment. Normally lime/cement and other pozzolanic materials are used as binder materials. In this work, it is proposed to use the efficiency of binding fly ash to improve the unconfined compressive strength (UCC) of soils, particularly during the curing period. This is because improvement in strength is a reflection of the improvement of bonding soil particles. Fly ash as the main source material, in addition to a minor proportion of cement and lime, is used to determine the strength. UCC test results revealed that as the percentage of fly ash increases there is an increase in compressive strength. It is also observed that with an increase in lime content and an increase in cement content, the UCC strength also increases. The strength in cement-stabilized compacted specimens is more compared to lime-stabilized mixtures. To confirm that the improvement in strength is related to the solidification of contaminated metals, particularly for soils containing copper and chromium, the stabilized mixture is tested for the leaching of these metals. Leaching tests were conducted on various stabilized mixtures at different curing periods. The leachate was examined for metal ion concentration using Atomic Absorption Spectrophotometer. The leaching behavior of heavy metals from different proportions of soil matrix revealed that with an increase in lime or cement percentage, a decrease in leachability is observed. It is found that the leaching of heavy metals from cement-stabilized soils was lower than in lime mixture combinations. However, minimum strength improves the solidification and retention of heavy metals effectively.

Impact of fly ash and bagasse ash on durability performance of lightweight concrete with the experimental study

Lightweight concrete [LWC] is rapidly reaching its full potential for a broad range of applications in the construction of concrete structures. It is tailor-made material for specific applications having beneficial properties. Therefore, the paper is devoted to the experimental analysis and study of fly ash and bagasse ash on the durability properties of lightweight concrete. Durability can be defined as the ability of the material to withstand the effects of its environment which are influencing the deterioration of concrete. The saturated water absorption and sorptivity was studied through experimental investigations, by varying the percentage of fly ash and bagasse ash content. Both fly ash and bagasse ash shows that the increase in the percentage of replacement leads to the more absorption of lightweight concrete. The results are investigated and presented on the studies conducted as follows, showing that the increases in the percentage of replacement, strength also increased.

Effect of Fly Ash and Steel Fiber Content on Workability and Mechanical Properties of Roadway Side Backfilling Materials in Deep Mine

The stable bearing capacity of roadside backfill body (RBB) is the key to control the surrounding rock deformation of gob-side entry retaining (GER) in deep mining. In this paper, slump and uniaxial compressive strength tests were conducted to study the changes of the slump and RBB mechanical properties of RBB fresh mixture under the influence of different percentages of fly ash (FA), river sand, and amounts of steel fiber (SF) admixture. The results show that (1) the slump first increases and then decreases with the increase of the FA proportion, while 20% of FA proportion is the critical point. In addition, SF has little influence on slump. However, when the proportion of FA is 60% and the content of SF is 0.4%, the slump reaches the minimum value of 130 mm. (2) The peak strength and residual strength increase with the increase of the FA proportion, and the strength gain starts to decrease when the FA proportion exceeds 40%. Moreover, SF only has a small effect on the peak strength when the dosage is 0.8%. (3) The post-peak strain difference decreases with the increase of the FA proportion and increases with the increase of the SF content. The addition of SF can make up for the reduced capacity of RBB to post-peak deformation caused by the addition of FA to a certain extent. (4) The addition of fly ash does not change the brittle failure mode of RBB. Furthermore, after the addition of SF, RBB changes from brittle to ductile failure mode. This study can provide experimental and theoretical basis for improving the bearing capacity of RBB and maintaining the stability of GER.

Bond strength of the interface between concrete substrate and overlay concrete containing fly ash exposed to high temperature

Bond between substrate and overlay concretes is a key factor for the success of the repair method and significantly influences the structural performance of the repaired element. This study investigated the effect of fly ash and the surface preparation method on the bond strength of repaired concrete after exposure to high temperatures, that has not been comprehensively studied in the literature. For this purpose, overlay concretes containing 0, 5, 10, 15, and 20 % fly ash as a replacement by weight of cement were cast on the original concrete surface prepared by four methods namely, as-cast, wire brushed, grooved and grooved-wire brushed. The bond strength of the interface between concrete substrate and overlay concrete was evaluated after exposure to 23, 200, 400, and 600 °C temperatures for 1 h. The results showed that partial replacement of cement by fly ash in the overlay concrete increased the bond strength of repaired concrete by up to 71 %, depending on the amount of fly ash used, surface preparation method, and the temperature to which the sample was exposed. The maximum increase of bond strength was recorded for concrete containing 20 % fly ash when the wire brushed preparation method was adopted at temperature of 200 °C. However, surface preparation was the most influential parameter, achieving a bond strength gradual increase in order from as-cast, wire brushed, grooved to grooved-wire brushed methods. The results also showed that for most of the samples having similar surface preparation and the same percentage of fly ash, bond strength decreased with the increase of exposure to temperature; for example, for overlay concretes without fly ash, in as-cast and wire brushed surface preparation methods at temperatures of 400 and 600 °C, the bond strength has reached zero. On the other hand, for grooved and grooved-wire brushed surface preparation methods, the bond strength reduction was about 63 %, when temperature increased from 23 to 600 °C.

An innovative approach for the development of sound absorbing material using industrial wastes

For sound absorbing panels as noise barriers, a research study is carried out to design and develop a composite mix using industrial waste as Fly Ash (FA), Waste Tyre Rubber (WTR) granules with cement. The design mix is prepared in two stages. The first stage involves blending of Ordinary Portland Cement (OPC) by gradually increasing the WTR percentage in the mixture. In the second stage of the study, the WTR content was kept constant while the percentage of cement and FA varied based on the required binding properties of cement for further acoustical enhancement. Evaluation of engineering and acoustic properties conveyed an increment of 470 % in the void ratio, as well as a 192.7 % and 236 % increase in Average Sound Absorption Coefficient (ASAC) and Noise Reduction Coefficient (NRC) respectively in the first phase of the study. The void ratio is further enhanced by 18.8 % with a mere decrement of 3.6 % in the compressive strength and an observed increase in Sound Absorption Coefficient (SAC) by 18.2 % in the second stage of the study. The optimal design mix prepared by 50 % WTR and 40 % FA with 10 % of cement provides efficient acoustic properties in the frequency range 500–1600 Hz and 2500–6300 Hz. The composite matrix is cost-effective and provides engineering properties for developing sound absorbing panels as noise barriers specially to control traffic noise and honking. The utilization of industrial waste in the composite mix renders threefold environmental advantages i.e. reduction in waste volume by promoting recycling, no chemical treatment and also mitigation of noise pollution through noise barriers.

Prediction of Compressive Strength of Fly Ash-Slag Based Geopolymer Paste Based on Multi-Optimized Artificial Neural Network.

The fly ash-slag geopolymer is regarded as one of the new green cementitious materials that can replace cement, but it is difficult to predict its mechanical properties by conventional methods. Therefore, in the present study, the back propagation (BP) artificial neural network technique is used to predict the compressive strength of the fly ash-slag geopolymer. In this paper, data from the published literature were collected as the training set and the experimental results from laboratory experiments were used as the test set. Eight input parameters were determined, as follows: the percentage of fly ash, the percentage of slag, the water-cement ratio, the curing age, the modulus of alkali activator, the mass ratio of NaOH to Na2SiO3 and the moles of Na2O and SiO2 in the alkali activator. Three multilayer artificial neural network models were constructed using the Levenberg-Marquardt (LM), Bayesian regularization (BR) and scaled conjugate gradient (SCG) algorithms to compare the prediction accuracy of the compressive strength of the fly ash-slag geopolymer paste at different ages (3, 7, and 28 d). It was concluded that the training set error of the BR-BP neural network was the smallest. Ultimately, the hyperparameter optimization of the BR-BP neural network was carried out to compare the training set and the test set errors before and after the optimization, and the results show that the BR-BP neural network model with hyperparameter optimization had the highest prediction accuracy.