Amount Of Ash Research Articles

Thermal and catalytic pyrolysis of automotive plastic wastes to diesel range fuel

This study investigated the pyrolysis of automotive plastic wastes (APW) for the production of diesel-grade oil products using a modified calcium bentonite clay catalyst. The research aimed to optimize the process for maximum oil yield and diesel range organics yield. The APW was characterized by its chemical composition and physical properties and the optimal temperature and catalyst amount were determined for maximum oil yield and diesel range hydrocarbons. The results showed that the APW contained mixed Acrylonitrile Butadiene Styrene (ABS), High/Low Density Polyethylene (H/LDPE), Polypropylene (PP), Polystrene (PS) and fiberglass, with a large quantity of volatiles and ash. The average oil yield was higher in the catalytic process compared to that in the thermal process. Generally, higher temperature above 450 °C produced waxy oil, thus lower temperature favoured more Diesel Range Organics (DRO). Both processes yield similar yields of C8–C24 DRO, and in both cases, lower temperature favoured high yield of C8-C24 hydrocarbons. The catalyst significantly increased the yield of oil, but did not significantly increase C8–C24 DRO yield. The optimal conditions for a maximum oil yield of 78.6 % and DRO yield of 79.5 % was a temperature of 416 °C and 24.3 wt% clay. Thus, the modified calcium bentonite clay can be used to improve oil yield from pyrolysis of APW. The oil produced had properties such as calorific value (49.85 MJ/kg), flash point (113 °C) and total aromatics 3.55 area%, similar to those of commercial diesel, and comprised mostly of 2,4-Dimethyl-1-heptene (25.37 ± 2.01 %) of thermal and 2, 4 – Dimethyl – 1 – heptane (23.44 ± 2.42) in the catalytic process. The study suggests further research to explore different catalysts, maximization of both DRO and gasoline range organics, recover energy from residues, and conduct techno-economic assessments for plant-scale operations. Additionally, policies on the management of end-of-life vehicles should include provisions for stripping and segregation of plastic components by accredited providers for the purpose of plastics recycling.

High-Strength Self-Compacting Concrete Production Incorporating Supplementary Cementitious Materials: Experimental Evaluations and Machine Learning Modelling

AbstractThis study investigates mechanical properties, durability performance, non-destructive testing (NDT) characteristics, environmental impact evaluation, and advanced machine learning (ML) modelling techniques employed in the analysis of high-strength self-compacting concrete (HSSCC) incorporating varying supplementary cementitious materials (SCMs) to develop sustainable building construction. The findings from the fresh characteristics test indicate that mixes’ optimal flowability and passing qualities can be achieved using different concentrations of marble powder (MP) alongside a consistent amount of silica fume (SF) and fly ash (FA). Moreover, the incorporation of 10% MP along with 10% FA and 20% SF in HSSCC significantly improved the compressive strength by 14.68%, while the splitting tensile strength increased by 15.59% compared to the reference mix at 56 days. While random forest (RF), gradient boosting (GB), and their ensemble models exhibit strong coefficient correlation (R2) values, the GB model demonstrates more precision, indicating reliable predicted outcomes of the mechanical properties. Following subsequent testing, it has been demonstrated that incorporating SCMs improves the NDT properties of HSSCC and enhances its durability. The finer MP, SF, and FA particles enhanced microstructural performance by minimizing voids and cracks while improving the C–H–S bond. As noticed by its lower CO2-eq per MPa for SCMs, the HSSCC mix with up to 15% MP inclusion increased mechanical strength while reducing the environmental footprint, making it an eco-friendly concrete alternative.

Valorization and investigation of volcanic ash as an aggregate building brick component

Abstract The devastating series of Taal volcanic eruptions from 2020 to 2022 covered several locations in the Philippines under a thick layer of ashes, destroying properties and halting business operations. In response, the Biñan City Government in Laguna, Philippines, proposed the development of eco-friendly bricks by leveraging the pervasive amounts of spewed volcanic ash as part of its solid waste management program. The materials recovery facility of the city produced several brick blends of combined Taal volcanic ash, cement mortar, and plastic waste materials. This study investigates the potential of Taal volcanic ash as an aggregate building brick component by measuring the compressive strength of the formulated bricks. With different blends of aggregate components, the bricks were tested for their durability based on the ASTM C67/C67M-20 standard after curing between 15 to 30 days. Per the ASTM C62-17 standard, all brick blends that were cured for 30 days including those with volcanic ash and plastic waste as aggregate components fall under the negligible weathering grade. This indicates that these bricks will be durable in building and structural applications where the average compressive strength requirement for bricks is at least 10.3 MPa. A regression model was also fitted with an adjusted r 2 value of 0.9413 and a p-value of < 2.2 × 10−16 using the experimental data.

The effect of Dolomite powder and Fly ash on durability properties of self-compacting concrete

Abstract This study aims to assess the effectiveness of dolomite mineral admixture in the production of self-compacting concrete (SCC). The characteristics of concrete at 7 and 28 days of hardening were evaluated. SCC mixtures with different amounts of dolomite powder and fly ash (FA) at a constant composition were made. It has been noted that the flow ability of SCC mixes gets better with increasing percentages of dolomite. In addition to its mechanical characteristics, the durability of mixes containing SCC has been studied, including water absorption, sorptivity, and permeability to chloride ions and acid attack. After 28 days, a strength of 61 MPa was achieved with a 20% DP replacement level mixture, which is 31.38% higher than the control SCC mix. Along with the compressive strength of SCC, parameters affecting the durability of SCC such as Rapid chloride penetration test (RCPT), Sorptivity, water absorption and hydrochloric acid attack were also studied at 28 days. The utmost resistance to permeability of chloride ions was attained.

Enhancing wear resistance of aluminum 6061 composites with fly ash: A sustainable approach for industrial applications

This study investigated the benefits of adding fly ash as a reinforcement material. The benefits included cost-effectiveness, improved quality, isotropic behavior, and environmental advantages. To improve self-lubrication and wettability behavior, Al6061 alloy composites were fabricated with different amounts of fly ash (0%, 2%, 4%, 6%, and 8% by weight), along with a fixed amount of graphite (3wt.%) and magnesium (2wt.%). Wear tests were conducted using Taguchi’s Design of Experiment (DoE) approach on the composites. The optimized composition with 6% fly ash exhibited the least wear rate under the test conditions of load = 10 N, sliding velocity = 3 m/s, and sliding distance = 2 km. SEM images revealed a uniform distribution of fly ash and graphite reinforcement in the matrix, contributing to enhanced wear resistance. The composites exhibited fewer scratches and plastically deformed surfaces, indicating a decrease in wear rate and increased wear resistance with higher fly ash content. ANOVA were used, and four parameters were identified to be critical, Composition at 34%, Sliding Distance at 27%, load at 23%, and Sliding Velocity at 12% contribution with a statistical confidence of 95%. This research contributes to developing cost-effective and environmentally sustainable materials with improved mechanical properties. It makes them suitable for various industrial applications, such as the automotive industry, where wear resistance is essential.

Replacement of conventional aggregates and fillers with steel slag and palm kernel shell ash in dense-graded asphalt mixtures

Large quantities of steel slag and palm kernel shell ash (PKSA) – waste products from steel production and palm oil milling, respectively – are generated annually in several countries, and their disposal is challenging. Meanwhile, the over-reliance on conventional rock aggregates for asphalt mixture production poses increasing sustainability challenges. This study investigated the potential of entirely replacing granite aggregates with steel slag and PKSA in a dense-graded asphalt mixture. Two sets of asphalt mixtures were prepared; the control mixture contained crushed granite aggregate and hydrated lime, while the other set incorporated steel slag as coarse aggregate and PKSA as fine aggregate and filler. Both mixture types utilized AC-30 viscosity-graded asphalt binder. The properties of the waste materials met the quality standards required for aggregates in asphalt mixture production. Both mixture types were designed according to the Marshall design procedure and were evaluated for durability (Cantabro abrasion loss), fatigue cracking Resistance, rutting Resistance, and moisture damage susceptibility. The Cantabro abrasion loss test indicated that the waste-based mixture was 3% less durable than the control. However, the cracking Resistance of the waste-based mixture was approximately twice that of the control. Even though the rapid rutting test indicated that the control mixture was slightly superior in rutting Resistance, the Marshall quotient suggested otherwise. Both mixture types exhibited similar moisture damage resistance. Overall, the steel slag and PKSA samples have shown high potential to replace virgin granite aggregates and lime in asphalt mixtures fully and are, thus, recommended for field performance evaluation and possible adoption.

RESEARCH OF THE POSSIBILITY OF USING CHP ASH IN THE PRODUCTION OF FIRED ASH GRAVEL

The article presents a comparative analysis of the characteristics of the dump ash of the Kyzylorda CHP hydraulic removal. A huge amount of ash, slag waste is collected in the dumps of the CHP, their accumulation in the dumps leads to a violation of the ecology of the environment. The issue of ash, slag waste disposal is an urgent problem. The use of ash and slag not only solves the issue of availability of raw materials, but also allows to improve the quality of products while reducing their cost. One of the valuable components of ash and slag waste is hydraulic removal ash. Hydraulic removal ash as a raw material can be used for the manufacture of artificial concrete aggregates (ash, agglomerate gravel, etc.). Studies were conducted to study the physico-chemical composition, determine the specific effective activity of natural radionuclides, loss during calcination of two types of hydraulic removal ash samples from Kyzylorda CHP (black and gray), which differ in sampling sites from ash dump. When studying the properties of the ash, X-Ray phase analysis was carried out, with the help of which the phase composition of the ash was determined. Work was carried out on the X-Ray phase analysis of ash, determination of the specific effective activity of natural radionuclides, calcination losses, which showed the possibility of using ash for the production of building materials. The conducted studies have confirmed the expediency of using the ash of the Kyzylorda thermal power plant in the production of fired ash gravel.

Assessment of functional quality changes in water chestnut enriched flaxseed nutritional laddu during storage

The present investigation was conducted to assess functional qualities of water chestnut enriched flaxseed nutritional laddu. The quality evaluation of the nutritional laddu was done up to 20 days of storage. These laddu contained appreciable amounts of crude protein (24.22%), crude fat (28.25%), crude fibre (9.95%) and total ash (4.86%). All of these decreased during storage periods in all the treatments. The maximum L* value (53.133) was found in T6 (20% Flaxseed + 30% Water chestnut + 45% Jaggery + 3% Ginger + 2% Dry fruit) at 20 days and minimum (38.170) in T0 (50% Flaxseed + 45% Jaggery + 3% Ginger + 2% Dry fruit) at 0 day of storage period. The highest total ash was found in T6 (5.530) at 0 day and lowest in T0 (3.100) at 20 days. It was concluded that up to 30 % water chestnut can be incorporated in flaxseed laddu to obtain best overall acceptability. Bangladesh J. Bot. 53(3): 561-566, 2024 (September)

Substantial CO2 uptake by biomass ashes under natural condition in China

A considerable amount of biomass ashes, resulting from agricultural waste field burning, wildfire, and solid biofuel incineration, is typically discarded in field or stored in dumps, where the alkaline oxides (CaO, MgO) they contain undergo carbonation and weathering-erosion processes over extended periods, continuously absorbing CO2 from the atmosphere and soil. However, their CO2 absorption behavior under natural conditions remains insufficiently explored in China. Using life cycle assessment (LCA) and material flow analysis (MFA) methods, this study developed a CO2 absorption analysis model for biomass ashes under natural conditions. We estimated the CO2 absorption of 9 different types of biomass ash from 1950 to 2022 through Monte Carlo uncertainty simulation. The results show that biomass ashes in China absorbed approximately 24.17Mt/year (95 % CI, 11.10–43.56) of CO2 under nature conditions, with the annual average CO2 uptake showing a steady increase from 1950 to 2022. The total CO2 uptake reached 856.85Mt (95 % CI, 368.73–1526.01) over these decades, mainly due to the significant contribution of biomass ash produced by domestic straw burning and fuelwood combustion, which accounted for 51.97 % and 22.08 %, respectively. Our findings highlight the substantial carbon sink benefits of biomass ash, providing valuable insights for further studies on carbon cycles in natural ecosystems and the potential integration of biomass ash in Carbon Capture, Utilization, and Storage (CCUS) technologies.

Cell Experiment Equipment by Using Ashes as Electrolytes

This article presents information about an experiment on how to create simple galvanic cell experiment equipment by using waste ash from burning as electrolytes, a copper plate as a cathode, and a zinc plate as an anode. The main purpose is to create a set of experimental equipment for teaching physics under the title of electrochemistry, to examine the possibility of generating electricity from ash, to study the change of the mixture ratio between the ashes and water that affects the open circuit voltage (OCV), to compare the value of the open circuit voltage from the sedimentation ashes electrolyte and non-sedimentation ashes electrolyte, and to study the pH value of the ash’s electrolyte within two hours. The research revealed that it can create five sets of galvanic cells by using different quantities of ashes, and it was found that the ashes from burning can generate electricity. The same type of ash with a different quantity will give almost the same OCV values, and changing the mixture ratio between ash and water will not affect the OCV values, which found that the mixing ratio between water and dry ash to become an electrolyte must use a minimum mixing ratio of water equal to ash or use a ratio of water more than ash to mix together. The results of measuring the value of OCV over a period of 2 hours found that the average value is almost constant, equal to 0.7 V. Here, we found that if the ash is allowed to settle, the value of OCV will decrease slightly, and if the ash is not allowed to settle, the value of OCV is constantly unchanged. It was also found that the pH value of the ash in each galvanic cell during the period of 2 hours was the same, with an average high alkalinity of about 13. This shows that alkaline electrolytes can generate electricity and have almost constant electricity. These five devices can be applied as a teaching tool for the Physics and Chemistry subject in the title of electrochemistry for students at the secondary school level and bachelor’s students because of an easy way to fabricate galvanic cells. The materials used are cheap and easy to find. It can also be used to study the characteristics of electrical conductivity in ash’s electrolyte and the characteristics of ash’s electrolyte.

Comparing durability and compressive strength predictions of hyperoptimized random forests and artificial neural networks on a small dataset of concrete containing nano SiO2 and RHA

Through the increasing use of supplementary cementitious materials, the properties of concrete have taken on increased significance in a design code. Using reliable prediction models based on a small data set for the mechanical properties and durability of concrete can reduce the number of trial batches and experiments needed to produce useful design data in the laboratory, reducing time as well as resources. In this study, we investigate how the properties of water penetration, chlorine resistance, and compressive strength can be predicted by polynomial regression (PR), random forest (RF) regression, and artificial neural networks (ANNs) based on the input values of density, workability, and the constituent amount of rice husk ash, cement, and nano SiO 2 . We vary the training data used and test the coefficient of determination ( R 2 score) on the remaining data as a test set to measure predictive capability. We show that RFs and ANNs outperform PR in all settings and have unambiguously extrapolating properties when hyperparameter optimization is designed for this purpose. Remarkably, we obtain R 2 scores on the test data of 0.858 − 0.990 for RFs and 0.825 − 0.985 for ANNs.

Tuff deposits as preservational context for a Miocene continental mammal assemblage from Patagonia, Argentina

The CO tuff is one of the volumetrically largest volcaniclastic events so far recorded in the Early-Middle Miocene Santa Cruz Formation (Patagonian Argentina). It represents aeolian processes, related with westerlies, that reworked and transported enormous quantities of volcanic ash from the Andes into the continental interior that accumulated in fluvial floodplain deposits. This volcanic event generated a major environmental change at ∼17 Ma (Burdigalian) and hostile living conditions for the biota of the area, at least during the time of deposition. We performed here a comprehensive study including taxonomic, sedimentological, and taphonomic aspects of the mammal assemblage recovered from this tuff deposit. The assemblage is constituted by representatives of Microbiotheria, Paucituberculata, Folivora, Cingulata, Rodentia, Notoungulata, and Litopterna, reflecting a wide mammalian diversity. The formation of the assemblage can be linked to a normal attritional model, in which the death of the individuals and subsequent deposition and burial of their remains would have occurred gradually over time, simultaneously with the accumulation of volcanic ash, at the place of death or very close to it. The time between the death and burial would have been relatively short, in accordance with the rapid and continuous influx of volcanic ash to the depositional environment. This multidisciplinary study allows us to interpret and reconstruct the possible taphonomic pathways of the mammal assemblage and to provide novel information on this particular preservation context linked to volcanically-influenced fluvial environments.

Effect of bacteria-fly-ash based binder on cemented tailings backfill: Mechanical strength, solidified mechanism and economic benefits

In order to investigate the effect of bacteria-fly-ash based binder on the properties of tailings backfilling material, the relationship between bacteria-fly-ash based binder and compressive strength, water-holding capacity, permeability of cemented tailings backfill (CTB) were analyzed. The result illustrated that bacteria-fly-ash based binder can improve CTB performance with low water-holding capacity and permeability. With increase of bacterial proportion, compressive strength was obviously improved. Adding appropriate amount of fly ash can improve compressive strength of CTB. The maximum compressive strength of 7.02 MPa was obtained when bacterial proportion and fly ash were 100 % and 20 %. 16S rDNA analysis illustrated that fly ash had a significant effect on bacterial community succession. Fly ash was closely related to relative abundance of bacterial species and PCA. Besides, possible mechanism suggesting KFe3(SO4)2(OH)6, (NH4)Fe3(SO4)2(OH)6, (KH3O)4Fe3(SO4)2(OH)6 and C-(A)-S-H gel to strengthen connection of tailings particles, fill pore structure in CTB and improve compactness of CTB were proposed.

Eco-Efficient Mortars for Sustainable Construction: A Comprehensive Approach

Cement production is responsible for approximately 7% of global carbon dioxide emissions. Despite our efforts, we have not been able to find a competitive substitute that is both reliable and environmentally friendly. The easiest way to solve the issue is to rationalize resources and try to minimize their use by replacing them with other materials. The current market shortage and reduced initial strength have limited the availability of blends that contain a significant amount of fly ash. Given the current economic, political, and environmental circumstances, it is predicted that a solution may be ternary blends with cement, fly ash, and MTK. Despite being “ancient” materials, there have been no recent global performance assessments. In this context, an investigation was carried out with ternary blend mortars. A significant volume of cement has been replaced with fly ash and metakaolin. The results show that these blends’ performance is promising because they offer a wide range of possibilities for replacing cement, maintaining or even improving its properties. MTK and fly ash’s synergies significantly enhance mechanical performance and durability. Furthermore, the global sustainability analysis shows that ternary blends are 36% more efficient than binary blends of cement and fly ash or metakaolin.

Analysis of mechanical properties of basalt fabric reinforced fly ash filled vinyl ester composites using multi criteria decision making technique

The current research was to examine the mechanical properties of composite material made of vinyl ester filled with fly ash of various weight percentages. Before fabrication the amount of fly ash and resin were identified by using the Multi Criteria Decision Making technique (MCDM). The best filler weight percentage of 5 wt% is determined by using Weighted Aggregate Sum Product Assessment (WASPAS) which is one of the MCDM methods. The virgin samples of vinyl esters are mixed with weight of 5 wt%fly ash by incremental of 5 wt% up to 20 wt%. All the mechanical tests of the specimen were conducted as per ASTM standards. Subsequently based on the results from the WASPAS method of fly ash content, the basalt fabric was reinforced with fly ash filled vinyl ester to fabricate the hybrid composites. By the mixing of fly-ash with vinyl ester the strength of the fly ash filled composites has been found to be enhanced in the filler. The results from the mechanical testing signified that fly ash can be used as filler material in basalt fabric reinforced vinyl ester resin. The fly ash infused basalt fibre reinforced yields significant development in mechanical performance contrast to the other fabricated composites.

Nutritional Evaluation of Eri Silkworm Pupa Strains: Addressing Entomophobia and Promoting Entomophagy

Samia ricini widely known as Eri silkworm is a commonly reared lepidopteran throughout the year. Six different strains of Eri silkworm are present, named according to their body pattern and color - greenish blue zebra (GBZ), greenish blue spotted (GBS), greenish blue plain (GBP), yellow zebra (YZ), yellow spotted (YS) and yellow plain (YP). Apart from being reared mostly for Eri silk, this lepidopteran insect is also considered as a popular delicacy among the tribes of Northeast India, along with it being moderately famous among the locals too. The proximate analysis of the lyophilized samples was carried out as per AOAC (2015) guidelines and mineral analysis was carried out in atomic absorption spectroscopy. Among the six different strains, YS contained highest moisture (7.82 gm) and crude fiber content (18.8 gm), whereas, YZ showed highest amount of total ash (4.32 gm) and crude fat content (22 gm). Furthermore, carbohydrate content was seen to be highest in GBS (14.41 gm). Hence, this study is aimed to unveil the nutritional worth of the six distinct pupa strains of Eri silkworm in an effort to dispel entomophobia, and promote entomophagy owing to the nutritional benefit it offers.

Evaluation of carob tree (Ceratonia siliqua L.) pods, through three different drying techniques, and ultrasonic assisted extraction, for presence of bioactives

The Mediterranean evergreen carob tree (Ceratonia siliqua L.) produces pods, that may be edible and even therapeutic. The purpose of this study was to determine how ethanolic extracts of carob pods from Morocco, prepared with ultrasonic assistance were affected by microwave (525 °C for 2.5 min), hot air (65 °C for 16 h), and spray drying (input and output air temperatures 180 and 90 °C, respectively, feed flow rate 2.5 mL/min and 5 bars, respectively), in terms of their physicochemical composition and biological activity. Colorimetric techniques were utilized to ascertain the phytochemical contents of pod extracts, whereas standardized in vitro methodologies were employed to quantify the antioxidant and antimicrobial activities. Physicochemical analysis showed that microwaved powders of carob pods presented significantly high (p<0.05) values of L* (62.15±0.06) and b* (21.32±0.06), and lower values of a* (4.16±0.03), as compared to spray dried and hot air-dried powders. Significantly high (p<0.05) amounts of ash (3.92±0.05 %), fat (1.48±0.02 %), fiber (7.45±0.12 %) and protein (2.65±0.06 %) were found in microwave dried powders, followed by spray dried and hot air dried. Significant difference in macro and micro minerals among three powders was also observed, as microwave dried powders were found to be significantly high (p<0.05) in Mg, K, Ca, Fe, Zn and Mn, followed by spray dried powders, whereas hot air-dried powders presented lowest values. Similarly, spectrophotometric analysis of phytochemicals revealed that ultrasonic assisted ethanolic extracts of microwave dried powders were found to be highest in total phenolics, flavonoids and carotenoids, with values 69.18±0.15 mg GAE/g, 34.88±0.08 mg QE/g and 24.05±0.15 mg g-1, respectively. In vitro antioxidant and antimicrobial analysis also showed a similar trend as, extracts of microwave dried powders exhibited significantly high (p<0.05) antioxidant and antimicrobial activities, followed by spray dried and hot air-dried. As compared to hot air and spray drying, the microwave drying and ultrasonic assisted extraction using 70 % ethanol as solvent could be employed on carob pods, to obtain powders and extracts, respectively, with minimum degradation of physicochemical characteristics, and maximum retention of nutritional, bioactive and antioxidant contents. Practical applicationsIn recent years, Morocco has become more and more dependent on the use of carob fruit and its powders. Nonetheless, very rare is known about the composition and carob pod quality of those grown in Mediterranean nations. The current study presents a comparison of the effects of three distinct commercial drying methods on the composition and physical characteristics of flour made from carob pods. The study's findings can also be used to evaluate how well information is composed, processed, and preserved for use in future research and commercial applications.

Microwave-induced plasma optical emission spectrometry (MIP-OES) analysis of the major elements in woody biomass ash following microwave acid digestion

The increasing use of woody biomass for sustainable heat and power is generating large amounts of woody biomass ash (WBA), which needs to be safely disposed of or recycled. In this study, the utility of Microwave-induced plasma optical emission spectrometry (MIP-OES) with microwave-assisted acid digestion for simplifying analyses of the major elements of WBA was investigated. Calibration curves exhibited good linearity (R2 > 0.999). Internal standardization using three emissions lines (324.754 nm of Cu, 451.131 nm of In and 371.029 nm of Y) showed that calibration with Cu (324.754 nm) correction resulted in the best linearity. Physical effects, even the presence of hydrofluoric acid or boric acid in mixed acids used for digestion, were of trivial influence with internal standard recoveries were within 0.95 to 1.05 times those of the blank sample. The limit of detection of MIP-OES for seven measured elements was 0.85–89 μg/L, 0.23–2.8 times higher than that of inductively coupled plasma optical emission spectrometry (ICP-OES). The recovery of elements in a certified fly ash reference material as determined by MIP-OES was 0.80–1.08. Elemental quantification of WBA samples by MIP-OES showed a strong correlation with that by ICP-OES. However, in a Welch's t-test, the MIP-OES values were significantly higher for K and significantly lower for Al and Ca in a majority of the samples. Nonetheless, considering the good correlation between their results, MIP-OES can replace ICP-OES for the analysis of WBA.

Performance optimization design of high ductility concrete rapid repair material incorporating coal gangue aggregate

In order to solve the problem of efficient and effective repair after brittle cracking of concrete on road and bridge deck pavements, and to consider the resource utilization of coal gangue solid waste, the river sand was replaced by coal gangue and a high ductile concrete rapid repair material (HDCRRM) was prepared through performance optimization design. First, the fluidity and compressive strength of materials mixed with different amounts of sulfoaluminate cement (SAC), fly ash, lithium carbonate, calcium hydroxide, calcium formate, sand-binder ratio, water-binder ratio and polycarboxylate superplasticizer were studied, so as to determine the preferred benchmark mix proportion. Then, the replacement rate of coal gangue was optimized to develop HDCRRM. Test results show that the reduction of SAC cement and the increase of fly ash content can weaken the compressive strength of material. The rational design content of lithium carbonate, calcium hydroxide, calcium formate, sand-binder ratio, water-binder ratio and polycarboxylate superplasticizer all can improve the fluidity and compressive strength of the materials within a certain range. When the replacement rate of coal gangue aggregate increases, the tensile elastic modulus and ultimate tensile strength of HDCRRM material decrease, while the ultimate tensile strain increases. When the replacement rate of coal gangue aggregate is 100 %, the compressive strength of HDCRRM is 40.5 MPa, the ultimate tensile strain is 2.83 %, and the average crack width is 50.27μm. The early compressive strength of HDCRRM is mainly provided by a large amount of ettringite and C-S-H gel.

Geotechnical and microstructural analysis of high-volume fly ash stabilized clayey soil and machine learning application

The weak soil stabilization using solid wastes is one of the most common solutions for improving geotechnical characteristics as well as for problematic waste dumping in landfills. The present experimental study aims to examine the effect of high-volume Class-F fly ash on the geotechnical and microstructural properties of clayey soil by adding them in ranges between 5 % and 50 %. The results show that as the amount of fly ash in clayey soil increases, properties like the specific gravity, plasticity index, permeability, optimum moisture content, maximum dry density and free swelling index improves. Moreover, these geotechnical properties were analyzed to develop machine learning models using three different algorithms, namely K-nearest neighbor regression, random forest, and support vector regression, for obtaining the optimum amount of fly ash contents in weak expansive soils. The predicted and experimental results found to be in close-relation for predicting the geotechnical behavior of modified clayey soil. Furthermore, the performance of the ML models degrades as the number of components reduces, with KNN regression consistently outperforming SVR and RF but suffering significantly with fewer components. The results of the testing set in the case of four components are MSE of 77, R² of 0.896, RMSE of 0.846, MAE of 0.327, and SEE of 0.858, indicating precise and consistent predictions. However, the prediction accuracy considering lesser components shows MSE as 262, R² as 0.648, MAE as 5.606, SEE as 16.707, and GPI as 1.056, confirming the elevated error rates. Overall, it has been concluded that combining comprehensive experimental work and machine learning techniques outperforms in enhancing geotechnical data processing, optimized waste contents in weak soils, improves sustainability in construction, saves resources, reduces the possibility of human mistakes, and increases reliability.