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Experts in the Netherlands have lately debated the novel policy idea to freely apply municipal solid waste incineration bottom ash (MSWIBA). In this paper, we map this ambivalent and unforeseeable, subjective, expert debate. This will help policymaking because more knowledge on subjective expert viewpoints and perceptions allows for clustering conflict and consent as well as gaps in common understanding in this complex debate. We applied Q-methodology which resulted in four distinct perspectives in the expert debate that reveal insights into the social licence to operate and into the legitimacy of the novel bottom ash regime. The freely applicable quality of BA itself is accepted in all perspectives. Conflicting views were found about new risks, trust and socio-political acceptance of the novel BA applications. An important practical contribution of this study is that a higher acceptance of the freely applicable MSWI BA quality in the Netherlands within the expert community can be achieved if the new risks of the free application regime are tackled. We are the first to use Q-methodology in this field, and our academic contribution is that we show that this method can be a helpful tool to unravel complex expert debates also related to MSWI BA applications. [ABSTRACT FROM AUTHOR]

Uplifted occurrences of fine-grained glaciogene marine sediments are found throughout the northern hemisphere. These sediments could be used to produce local construction materials, to rely less on imported construction materials from southern regions. In this study, a representative occurrence from Ilulissat, West Greenland, was investigated as a potential resource for local brick production. The study comprised three parts: (1) raw material characterization based on grain size distribution, major element chemistry, including total carbon, sulfur, and chloride concentrations, mineralogy, morphology, and Atterberg limits; (2) the production of test bricks at a Danish brickwork; and (3) testing of the bricks based on total shrinkage, water absorption, hygroscopic adsorption, open porosity, bulk density, compression strength, and mineralogy. The bricks produced proved to have excellent compression strength, low open porosity, and low water absorption. The shrinkage could be reduced by adding 10% chamotte to the marine sediment. Based on the investigated properties, this indicates that this type of clay is highly suitable as a resource for bricks. [ABSTRACT FROM AUTHOR]

In this work, the Taguchi experimental plan and the gray relational method are used to make new biochar additive enhanced areca-toughened polyester resin composite rebar material for various construction applications. Three different fiber length, thickness, and biochar volume percentage were used to make the rebar along with constant biochar size. A total 9 sets of composite rebars were made according to Taguchi experimental plan, and the most prominent process input is identified. According to the results, the experimental pattern A2B3C1 is the most likely to lead to better results generally. This set of experiments led to a GRG of 0.741 with a tensile strength of 49.54 MPa and a water absorption % of 1.3. Based on the min–max difference level, it is found that the most important process variable was the length of areca fiber, followed by their diameter and biochar content. Also, the confirmation test showed that the newly optimized set of process variables A3B1C1 gave a refinement in GRG of 0.756 with an improvement of 2.01%, which is the same as an increase in tensile strength of 50.57 MPa and a decrease in water absorption of 1.27%, respectively. These biochar–areca fiber-dispersed polyester composite rebar made from domestically discarded vegetable wastes could be used in modern building applications with less impact on the environment. These materials could be used in the development of RCC pre-casted slabs, manhole covers, hand rails, roof fencing, and stairs of inner and outer portion of living area. [ABSTRACT FROM AUTHOR]

Abstract This study investigated the mineralogical assemblage of weathering products developed on mylonite rocks in west Cameroon. Smectite and vermiculite occurrence was studied, particularly to emphasize its origin and the potential of the samples in terracotta production. Samples characteristics were determined through X-Ray Diffraction (XRD) and X-ray Fluorescence (XRF) methods. Weathering products were observed along road trenches of 450 m long and 50 m height on a syenitic basement rock intruded by magmatic rock veins. Clay minerals are mainly composed of kaolinite and illite. 2:1 swelling clay minerals (vermiculite, montmorillonite) occur in some samples mainly originated from the contact between weathering materials and quartzo feldspatic bands. The main oxides are SiO2 (46–72%), Al2O3 (16–31%), Fe2O3 (2–16%) and K2O (0.1–6%). Vermiculite may be formed by fluid-mineral interactions during alteration of the chlorite in the plasmic microsystems of the soil. Structural changes in the upper part of the saprolite leading to the transformation of vermiculite into smectite under supergene alteration control, which predominates in humid tropical zones. Heavy rainfall leads to the formation of kaolinite at the expense of 2:1 clay minerals. Empirical classification revealed that the studied weathering products can be used to produce common bricks.

Today there is no unified personalized approach to the selection of construction materials in orthopedic dentistry, hence it is necessary to introduce and further study the effect of construction materials on the microbiota of the oral cavity. In particular, principles of microbial adhesion to various construction materials, development of biofilm and bacterial colonization of concrete construction materials need to be analysed. The article provides a review of literature devoted to the description of the adhesive properties of oral microbiota to orthopedic materials from the groups of polymers, metals and ceramic constructions as well as the development of the negative impact of the construction material on the microbiota of a particular group of teeth and the general condition of the microflora of the oral cavity, increase of the risks of dental plaque formation, biofilms formation and a shift of microflora towards the predominance of cariogenic one.

Abstract Recently, research results on PC-based or alkali-activated slag cement (AASC) using seawater as mixing water have been reported. Unlike seawater, reverse osmosis brine (brine) is waste discharged into the ocean from seawater desalination plants. There is a need to develop new and effective methods of disposing or utilizing brine to reduce marine pollution, protect marine ecosystems, and increase marine plant construction. However, research on cement or concrete using brine as a mixing water is very limited. Brine has almost the same composition as seawater, and the ion concentration is 2–4 times higher. Therefore, it is believed that new methods of using brine can be investigated and developed based on existing research and experimental results on seawater. The effects of brine and aluminum oxide (AO) on activated slag with calcium hydroxide (CH) were investigated for hydration and mechanical properties. 5% and 10% of CH were used, and samples using fresh water (FC) were prepared at the same time for comparison with brine. The slag sample without CH has a low initial (1 and 3d) strength of about 10 MPa for both FC and brine, but increases rapidly from 7d. Incorporation of CH was effective in improving the mechanical performance of FC and brine samples. In addition, the brine sample exhibited higher strength than the FC sample because it formed fewer C3AH6 phases that cause volume instability than the FC sample and affected the hydration promotion of slag particles. And more calcite phases were observed in the brine samples than in the FC samples. Through this study, the possibility of using brine as a building material was confirmed. In addition, the effect of chloride ion adsorption of slag mixed with AO and CH on the physical properties and mechanical performance of the hydration reaction was confirmed.

Recently, research results on PC-based or alkali-activated slag cement (AASC) using seawater as mixing water have been reported. Unlike seawater, reverse osmosis brine (brine) is waste discharged into the ocean from seawater desalination plants. There is a need to develop new and effective methods of disposing or utilizing brine to reduce marine pollution, protect marine ecosystems, and increase marine plant construction. However, research on cement or concrete using brine as a mixing water is very limited. Brine has almost the same composition as seawater, and the ion concentration is 2–4 times higher. Therefore, it is believed that new methods of using brine can be investigated and developed based on existing research and experimental results on seawater. The effects of brine and aluminum oxide (AO) on activated slag with calcium hydroxide (CH) were investigated for hydration and mechanical properties. 5% and 10% of CH were used, and samples using fresh water (FC) were prepared at the same time for comparison with brine. The slag sample without CH has a low initial (1 and 3d) strength of about 10 MPa for both FC and brine, but increases rapidly from 7d. Incorporation of CH was effective in improving the mechanical performance of FC and brine samples. In addition, the brine sample exhibited higher strength than the FC sample because it formed fewer C3AH6 phases that cause volume instability than the FC sample and affected the hydration promotion of slag particles. And more calcite phases were observed in the brine samples than in the FC samples. Through this study, the possibility of using brine as a building material was confirmed. In addition, the effect of chloride ion adsorption of slag mixed with AO and CH on the physical properties and mechanical performance of the hydration reaction was confirmed. [ABSTRACT FROM AUTHOR]

The establishment of many industries produces a large amount of by-products in solid, semi-solid, and liquid form because industrial waste can be toxic or non-toxic in nature, causing serious damage to the environment. India has a vast network of existing industries, and in the future, many more will produce millions of tons of various by-product materials. Pollution and disposal problems can be reduced by using these materials effectively in civil engineering projects. This paper examined the evaluation of red mud produced in the alumina processing industry to determine its suitability as a construction material based on physical, chemical, and other civil engineering properties. Red mud is the fine-grained residue that remains after alumina has been extracted from bauxite ore. About 10 million metric tons of red mud waste is generated every year in India, causing very serious and alarming environmental problems. Neutralizing this red mud would be very beneficial, as it would reduce pollution. In addition, the neutralized red mud could be reused in construction mixes and as a raw material. The physical, chemical, and geotechnical characteristics of these waste materials were critically evaluated for this purpose. It was found that red mud can be used as building material. [ABSTRACT FROM AUTHOR]

This study aims to evaluate the potential of polyethylene glycol (PEG 6000), a recycled material, as an additive to improve unfired clay bricks. By proposing a sustainable alternative to traditional methods potentially linked to medical waste. This research explores the physicochemical, mechanical and thermal properties of unfired clay bricks modified by different contents of PEG 6000 (0%, 1%, 3%, 7%, 15% and 20% by weight) according to the standard NM 13.1 0.0442005. The testing methods comply with recognized building sector standards (Belgian NBN EN 771-3+A1 and American ASTM C675-17). The clay used was extracted from Berrechid city and it is identified as kaolinite and some trace of illite, which has non-swelling properties. The incorporation of PEG 6000 into the unfired clay bricks has notably reduced the porosity rate from 3.91 % to 1.21 %, an improvement of 69 % compared to the reference sample, leading to a decrease in the rate of capillary water absorption. The bulk density of the bricks has slightly decreased to 1670.07 kg/m3, which still allowed them to be classified as light bricks. The incorporation of 7% of PEG 6000 increased compressive strength and flexural strength up to 15.98 MPa and 0.959 KN respectively, an improvement of 63.23 % compared to the reference sample, making them suitable for the construction of interior and exterior walls according to the standard NBN EN 771-3+A1. However, thermal conductivity and specific heat capacity have been improved by 42.22 % compared to the reference sample, reaching 0.26 W/m.K and 0.89 kJ/kg.K respectively. Optimization showed that 7% of PEG 6000 is the optimal percentage for manufacturing high-performance bricks, taking into account all properties studied previously. Moreover, the simulations carried out by the TRANSYS software suggest significant energy gains in terms of insulation, achieving up to 58.33% energy savings. In essence, this research demonstrates the potential of PEG 6000 as a sustainable additive for unfired clay bricks, offering improved properties and promising energy efficiency benefits.

Steel bars are part and parcel of reinforced concrete used in the construction projects, ranging from single family houses to super tall buildings and long span bridges. Maintaining the quality of the steel bars has always been challenging especially in developing countries. Low quality steel bars result in serviceability issues and reduce useful life of structures. This research work is focused on examining and investigating some basic facts about the quality of the steel bars produced in Pakistan. Pakistan being 5th most populous country in the world has huge consumption of steel. Laboratory testing data of steel bars are statistically analysed to have an insight in to the quality of bars. These steel bars were tested over a period of two years, which belong to several real-life projects. Properties like weight per unit length, yield strength, ultimate strength and percentage elongation were mainly analysed. Findings show that out of the stock of 4782 bars, 17.4 % failed to meet the minimum requirements provided by American Society of Testing and Materials (ASTM A615). Quality of grade 60 bars was found better than those of grade 40.

Shikarpur is one of the most historical place of Sindh, the history of this historical city begins from 1600 AD when Sindh was conquered by the Mughal Empires. The present city and its outskirts places were used as hunting fields known as Shikargah . Later on this historical place ruled by Daudpotas and Talpurs. In earlier 1800 British extended their trade to Central Asia through River Indus. In 1843 British conquered Sindh, Britishers given special attention towards Shikarpur due to its geographical location, an underground sewerage system was laid in 1890 AD, underground water supply were laid with a network of fire hydrants. as Shikarpur was the trade Hub of Central Asia and after getting special attention from Britisher, economically the city become more richer and Architecture of this city boast up people started built beautiful houses, community Havelis and other institutional Buildings by local Authorities. The workmanship and techniques of that era was very high, they were often to build two, three stories’ buildings by using local techniques, Material and workmanship. The constructions were not only functionally, structurally and aesthetically sound but also environment friendly. Scope of this research to investigate the construction techniques and material used in Heritage of Shikarpur. The research was conducted through the surveys and detailed inspection of British Era Buildings in different areas of Shikarpur city. [ABSTRACT FROM AUTHOR]

Structure-soil interface friction characteristics is of importance to investigate the interaction between engineering structures and soils, especially for offshore structures. The interface friction behavior between marine clay and structural materials with different roughness was studied in this paper by using 3D optical scanning tests, a modified direct shear device and numerical simulation. Relationships between the surface roughness of structures, water content and interface friction angle were presented by model tests. The increase of water contents decreased the interface friction angles. For interfaces with different roughness, the interface friction angles will be smaller than that of the soil when the water content exceeds a certain value. The roughness of the interface and the water content of the soil are mutually coupled to influence the coefficient of friction (COF). This paper proposed a Finite Element Method (FEM) to simulate the interface direct shear tests of structures with different roughness. The surface models with different roughness are established based on the structure data obtained by 3D scanning. The Coupled Eulerian-Lagrangian (CEL) approach was employed to analyse soils sheared by irregular surfaces. The interface behavior for interfaces with different roughness under cyclic shear stresses was analyzed by FEM. [ABSTRACT FROM AUTHOR]

Plastics, often known as synthetic polymers, have become an essential workhorse element in the contemporary marketplace due to their availability in a wide range of forms and adaptability. Despite its many advantages, the present plastic business has problems that are becoming more obvious by the day. Between 2000 and 2019, global waste plastic production more than quadrupled to 460 million metric tonnes. Only 9% is recycled, 12% is burned, and the rest is disposed of in the waste stream. As per the Down to Earth 2018 figures, India consumes over 16.4 million metric tonnes of plastic. In that, single-use plastics are made up of nearly 43% and were disposed of in landfills. Recycling possibilities include converting waste into raw materials for industry, producing fuel, and using it as construction material. Since buildings are intended to last for several decades, adding such waste materials into them helps to extend their life. It is thus conceivable to reduce both the amount of plastic waste put in landfills and the amount of natural resources mined for the production of conventional materials. This comprehensive review intends to logically analyze the findings of numerous researchers who introduced waste plastic in various forms (flakes, fibers, pellets, granules, pellets, and molten forms) into different building materials. This article supports the discussion of using waste plastic for sustainable building by offering details regarding the physical, mechanical, and durability strength properties of building materials containing various forms of plastic waste. The review analysis indicates that adding plastic waste, regardless of shape or particle size, tends to reduce the workability and mechanical properties of the resulting material. However, introducing plastic particles in small amounts, such as 2%–20%, helps to obtain threshold strength properties. The study also suggests that the addition of smaller particles with irregular forms helps to obtain better results than larger particles with uniform shapes and smooth surfaces. [ABSTRACT FROM AUTHOR]

Environmental and health risks posed by radionuclides in quarry pit soils are of great concern in environmental health monitoring. The current investigation was aimed at determining the natural radionuclide activity concentration (in Bq kg–1) of the understudied quarry pit granules used as construction materials. The collection and preparation of pit soil samples from Abeokuta quarry sites were done using standard methods, analysis of radiological parameters was carried out using hyperpure germanium (HPGe) spectrometer. Specific activity concentrations of 226Ra, 232Th, and 40K were measured. The values obtained were greater than the world weighted average of 35, 30, and 400 Bq kg–1 for 226Ra, 232Th, and 40K, respectively. The absorbed dose, the annual effective dose, and the radium equivalent were calculated and demonstrated significant values. The radionuclide content of the samples is relatively high and the use of pit soils as a building material, therefore, raises radiological concerns for dwellers in this area and requires periodic monitoring and undergoing a radiation protection program. [ABSTRACT FROM AUTHOR]

Uplifted occurrences of fine-grained glaciogene marine sediments are found throughout the northern hemisphere. These sediments could be used to produce local construction materials, to rely less on imported construction materials from southern regions. In this study, a representative occurrence from Ilulissat, West Greenland, was investigated as a potential resource for local brick production. The study comprised three parts: (1) raw material characterization based on grain size distribution, major element chemistry, including total carbon, sulfur, and chloride concentrations, mineralogy, morphology, and Atterberg limits; (2) the production of test bricks at a Danish brickwork; and (3) testing of the bricks based on total shrinkage, water absorption, hygroscopic adsorption, open porosity, bulk density, compression strength, and mineralogy. The bricks produced proved to have excellent compression strength, low open porosity, and low water absorption. The shrinkage could be reduced by adding 10% chamotte to the marine sediment. Based on the investigated properties, this indicates that this type of clay is highly suitable as a resource for bricks.

A tremendous amount of plastic and tire waste is generated every day. Pyrolysis gives a sustainable plastic and tire waste management solution by transforming them into high-value carbonaceous materials (i.e., char). Char made from plastic or tire waste can be used as a modifier for asphalt binder (i.e., bitumen), in order to improve the properties and performance of base bitumen. In most cases, the char is produced from waste feedstock at ≤300°C, most likely due to the high volatile matter content in feedstock. These chars have been proven experimentally to enhance the deformation resistance, rutting resistance, stiffness, and elasticity of bitumen. The optimal dosage of char in the modification process is highly associated with the kind of waste feedstock and pyrolysis conditions under which the char is made. The present review highlights the promise of the char materials derived from plastic and tire waste for use in materials applied to civil and construction industries, which is aimed specifically at expanding the application of chars made from plastic and tire waste beyond their typical applications, such as in environmental remediation and catalysts. [ABSTRACT FROM AUTHOR]

Copyright of Revista de Arquitectura (1657-0308) is the property of Universidad Catolica de Columbia, Facultad de Arquitectura and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

More than half of the materials extracted from natural environments eventually accumulate as building material stock (BMS). From a linear‐to‐circular economy perspective, BMS transforms the building sector from a virgin material consumer and a waste generator to a future depository of secondary resources. Studies characterizing the amount and distribution of BMS adopt different approaches, but high data requirements restrict their applicability. This research proposes an alternative method for regional BMS quantification. The method leverages the permanent population, electricity consumption, and BMS of a sample city to develop a statistical regression model; then uses it to estimate the BMS of a larger, homogenous region. With relatively low data requirements, the new method is especially applicable in underdeveloped areas where data required for BMS quantification methods are usually unavailable or incomplete. We apply the method to characterize the spatiotemporal evolution of BMS in China's Greater Bay Area. From 2000 to 2021, the total BMS in this region increased from 4.4 to 7.7 billion tonnes, with concrete, brick, and steel accounting for 72.32%, 17.57%, and 4.71% of the total BMS, respectively. The most rapid BMS growth occurred in Guangzhou (from 534.75 to 1277.82 Mt) and Shenzhen (517.80 to 1235.48 Mt). A core–edge BMS accumulation pattern emerged in this area while the BMS peak showed a coast‐to‐inland shift. Future studies can explore generalizing this new method to characterize BMS in other developing regions. [ABSTRACT FROM AUTHOR]

Copyright of SDU Journal of Engineering Sciences & Design / Mühendislik Bilimleri ve Tasarım Dergisi is the property of Journal of Engineering Sciences & Design and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

In this paper, two types of lightweight fly ash (FA) aggregates: cold bonded fly ash (CFA) and sintered fly ash (SFA) aggregates were prepared through the cold bonding and sintering method. During the pelletization process, different ratios of binders to fly ash were used, i.e., 10:90, 15:85, 17:83, and 20:80 with a set amount of water. Cement, metakaolin, sodium silicate, ureaformaldehyde resin, bentonite powder, and phenolformaldehyde resin were employed as binders. A comparative study on physicochemical, mechanical, phase identification, microstructure, and optical analysis of CFA and SFA was performed. The results showed that CFA (an alkali binder) had a higher water absorption (WA) value of 9,50 % with a crushing strength (CS) value of 6,30 MPa than SFA (sodium silicate binder) with a CS value of 5,80 MPa and a WA value of 10,28 %. Experimental observations also demonstrated that the leaching ability of SFA was considerably lower than that of CFA. Most notably, SFA can be used as a substitute for construction material and structural applications along with solving FA waste disposal and related problems to a considerable extent. [ABSTRACT FROM AUTHOR]

AbstractThe construction material store (CMS) industry in Thailand is highly competitive, boasting 16,000 stores and experiencing rapid growth (GSB Research). Despite this, back-office management, such as delivery and appointment scheduling, struggles to keep up with the increasing customer demand. The present study aims to develop an operational model for efficient delivery planning in a CMS. The model accurately calculates the minimum delivery costs while adhering to certain constraints. This research employs a mixed-integer linear programming (MILP) mathematical model specifically designed for planning routes and organizing products for delivery. In this study, the CMS delivers products to customers through a third-party trucking company, and a practical delivery plan is developed based on existing conditions and limitations. The delivery plan ensures that products are supplied to customers using appropriate vehicles for the product type, while staying within truckload capacities. The CMS operates by outsourcing vehicles of various sizes, and different products are selected for delivery. All products are available for shipment to customers at any given time. The improved delivery planning considers routing, product selection for trucks, capacity limitations, customer demand, and distance management. Certain limitations of the model, such as routing policy, truck capacity, and product weight, are addressed. The results demonstrate that implementing this model can decrease planning time by up to 80%, reduce total costs by up to 20%, lower delivery distances by up to 19%, and enhance customer satisfaction.

Copyright of Engineering Mechanics / Gongcheng Lixue is the property of Engineering Mechanics Editorial Department and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The ceramic waste powder (CWP) is generated in the ceramic industry during the cutting and polishing stages. It is harmful to the environment and needs a massive area for disposal. Therefore, an alternative way is required to reduce the environmental pollution and landfill caused by CWP. The aim of the study is to establish an Artificial Intelligence (AI) model for CWP concrete from the experimental results to save time and cost. Advancements in AI have made the estimation of concrete mechanical characteristics possible by employing Machine Learning (ML) approaches. In the current study, 60 concrete mixes with waste CWP are made as a partial replacement of cement by 10% and 20%. The plain concrete's ultrasonic pulse velocity (UPV) is taken as a reference. Furthermore, supervised ML techniques (i.e., Bagging, XG Boost, AdaBoost) and standalone (Decision tree) are employed to foresee the UPV of CWP concrete (CWPC). The prediction model's performance is evaluated using R2, Root Mean Square Error (RMSE) values, and Mean Absolute Error (MAE). The k-fold cross-validation is used to validate the performance of the prediction model. The XG Boost model, with an R2 value of 0.95, performed better compared to Bagging, AdaBoost, and DT models. Among all ensemble and individual models, the XG Boost model performs better with higher R2 and lower RMSE (0.081 km/s) and MAE (0.063 km/s) values. Therefore, the CWPC, as a construction material, would reduce land degradation and water pollution. In addition, applying ML techniques for estimating concrete characteristics would have reduced the consumption of efforts, resources, and time of researchers in the construction sector.

The 21st century has seen a rise in the demand for building materials, which is not unconnected to the rise in population. The high demand has led to an increase in the price of such commodities as well as a strain on environmental resources and the call for more sustainable, and cost-effective alternatives to replace the conventional materials. In this study, waste glass powder was alkali-activated to produce geopolymer, which was combined with both fine and coarse waste polyethylene terephthalate (PET) pulverized plastics (aggregates). The product was then cured to form the ceiling board. The impact of the employed glass, alkaline solution, aggregate size, and aggregate content in the boards were then investigated. Board J with 92.5% PET particles (Coarse and Fine) and 7.5% Glass Particles gave the best water absorption (16.561%), thickness swelling (3.332%) and density test (0.918 g/cm3) results. It was found that the geopolymer with equal proportions of fine and coarse PET aggregates reduced the material's ability to absorb water and increased its density and swelling thickness. The modulus of rupture and modulus of elasticity of the boards were both enhanced by adding more glass powder and fine PET aggregates. However, it was discovered that the board's mechanical qualities, unlike its physical properties, were not improved by the addition of the geopolymer during manufacture.

Waste vitreous enamels from the heating device production process were used for partial replacement of cement in the mortar and concrete production industry. This waste, due to the high content of heavy metals, is classified as hazardous waste. At the same time, waste vitreous enamels possess pozzolanic activity and belong to class 15 (WEP—generated during the production process of heating devices, premix technology), that is 5 (WETM—generated during the production process of heating devices, classic technology) of pozzolanic materials. The purpose of this research was to develop new composites from these wastes to reduce the deposition of the toxic compounds and reduce their environmental impact. The chemical and physical-chemical characterization and pozzolanic activity of the raw waste materials were studied by a mixture of complementary methods, as well as physical-mechanical characterization and a leaching test of mortar and concrete composites. The results indicate that the replacement of cement with WEP up to 30%, or with WETM up to 20% does not significantly affect the quality of concrete in comparison to the quality of the reference concrete prepared with 100% cement. The leaching test showed no significant release of toxic elements for both obtained composites. [ABSTRACT FROM AUTHOR]

Leakage is one of the major problems facing the functionality and sustainability of dams. It occurs through the embankment body, reservoir, foundation, and abutments. This study was conducted to identify the main causes of the leakage problem at the Dora-1 dam, located in the northern part of Ethiopia. It is an earthfill dam with a height of 43.5 m, crest length of 454 m, and reservoir capacity of 4.67 million cubic meters. Part of the embankment body was wet and swampy up to 20 m high from the ground due to leaking water. Geological investigation, laboratory test of the construction materials (including grain size analysis, specific gravity and water absorption, Atterberg limit, free swell, dispersion, permeability, and shear strength), and electrical resistivity investigation were used to identify and pinpoint the possible causes of the leakage problem. Results of the study show that the favorable geological features responsible for the occurrence of leakage include: (a) geological contact between sandstone and moderately to highly weathered basalt unit at the left abutment, (b) the gravelly sand deposit at the central foundation and (c) dyke outcrop at the river course within the reservoir running in the upstream-downstream direction. Results of laboratory tests for clay core show medium to high compressibility, good to poor workability, and semi-pervious to impervious permeability when compacted. The water absorption and the percentage finer of the filter material don't satisfy the filter criteria and the shell material was found to be semi-previous. The anomalous in the resistivity survey result confirms the situation. Slope stability analysis of the embankment showed instability conditions at full reservoir level. Close follow-up and a downstream stabilization structure, including rock and gravel support, were recommended. [ABSTRACT FROM AUTHOR]

Stabilization of dredged sediment and reusing the mixture as a construction material is an effective way to reduce environmental problems and save natural resources. However, the crushing process that occurs during construction may affect the mechanical properties and leachability of the reused stabilized soil, an issue that is less reported. Therefore, consolidated undrained triaxial tests and semi-dynamic leaching tests were conducted on stabilized sediments and recompacted crushed stabilized sediment grains (SG) to evaluate the influence of the crushing process. The results of the triaxial tests showed that the stabilized sediment exhibited strain-softening and brittle behaviors under various confining pressures (100, 200, and 400 kPa), while strain-hardening and ductile behaviors were more obvious in the SG. The reduction in cohesion between stabilized sediment and the SG reflected a loss of cementation bonding during the crushing process. The overall leaching behaviors versus curing time of heavy metals (As, Cr, Cu, Zn, Pb, Ni, and Hg) in stabilized sediment was similar to that of SG. The leaching mechanism indicated a good immobilization of heavy metals in stabilized sediment, while their stability in SG was poorer. The reason for the differences in triaxial strength properties and leachability were mainly attributed to the fact that the strong cementation bonding was destroyed by the crushing process, weakening the soil structure and raising the potential for release of elements. [ABSTRACT FROM AUTHOR]

The solution of using organic and inorganic chemical agents to strengthen loading capacity of soil for base, subbase or surface layers in unpaved road pavement has been applied for a long time in the world. In Vietnam, the method has been applied with conventional such as lime, cement, fly ash, or bitumen. Since the years of 2000s, the new soil stabilizers have been introduced to Vietnam. However, the price of the imported admixtures is still the barrier for practical applications. DBS-06 is a domestic lignosulfonate soil stabilizer synthesized from the paper industry waste, which was collected from the HoaBinh paper factory located in Ky Son District, HoaBinh Province. The study program was conducted to investigate the main mechanical properties of the soil specimens stabilized by DBS-06intending for used in road construction. The test results showed that the soil treated with DBS-06 was significantly improved the strength of compression, split tensile and elastic modulus, the three critical indicators representing forload bearing capacity of the material, in both normal and water saturated conditions.

Abstract Agro-food (AF) industry provides great investment opportunities in its treated water and solid wastes, by conversion into value-added products. Our study accumulated extensive bibliometric data on this field from the Scopus database, between 1974 and 2021, and conducted a scientometric analysis using Science Mapping Analysis Software Tool (SciMAT) and VOSviewer for analyzing the retrieved data. The leading journals, highly used keywords in the published articles, authors and papers with the highest citations, and relevant regions were all identified in the scientometric analysis. Goal 6 of the Sustainable Development Goals (SDGs) pledge to “ensure the availability and sustainable access to water and sanitation for all.” To fulfill this demand, decentralized technologies are being developed. The scientometric analysis found significant flaws in previous studies on the adoption and use of decentralized treated AF wastewater, as well as its potential benefits for a sustainable future, particularly in the developing countries. Coagulation/electrocoagulation/ultrasonic processes, hybrid constructed wetlands and microbial inoculation are emerging efforts to achieve SDG6, particularly, in the emerging economy nations. Our scientometric findings can help academics collaborate on research, form joint ventures, and implement sophisticated technologies for treating AF wastewater and producing beneficial byproducts.