Search Results (48)

This study investigates the in-plane shear behavior of solid brick masonry walls, both unreinforced and retrofitted using Reinforced Khorasan Jacketing (RHJ), a traditional pozzolanic mortar technique rooted in Iranian and Ottoman architecture. Six one-block-thick English bond masonry walls were tested in three configurations: unreinforced with Horasan plaster (Group I), reinforced with steel mesh aligned to wall edges (Group II), and reinforced with mesh aligned diagonally (Group III). All the walls were plastered with 3.5 cm of Horasan mortar and tested after 18 months using diagonal compression, with load-displacement data recorded. A detailed 3D micro-modeling approach was employed in finite element simulations, with bricks and mortar modeled separately. The Horasan mortar was represented using an elastoplastic Mohr-Coulomb model with a custom softening law (parabolic-to-exponential), calibrated via inverse parameter fitting using the Nelder-Mead algorithm. The numerical predictions closely matched the experimental data. Reinforcement improved the shear strength significantly: Group II showed a 1.8 times increase, and Group III up to 2.7 times. Ductility, measured as post-peak deformation capacity, increased by factors of two (parallel) and three (diagonal). These enhancements transformed the brittle failure mode into a more ductile, energy-absorbing behavior. RHJ is shown to be a compatible, effective retrofit solution for historic masonry structures. Full article

Red mud (RM), a highly alkaline waste from alumina production, poses severe environmental threats due to massive stockpiling (>350 million tons in China) and groundwater contamination. This study evaluates three scalable strategies to repurpose RM: iron recovery via magnetic separation, sintered brick production using RM–fly ash–granulated blast furnace slag (6:1:3 ratio), and non-calcined cementitious binders combining RM and phosphogypsum (PG). Industrial-scale iron extraction achieved 23.85% recovery of iron concentrate (58% Fe₂O₃ grade) and consumed 3.6 million tons/year of RM, generating CNY 31 million annual profit. Sintered bricks exhibited 10–15 MPa compressive strength, meeting ASTM C62-23 standard while reducing material costs by 30%. The RM–PG binder achieved 40 MPa compressive strength at 28 days without cement or calcination, leveraging RM’s alkalinity (21.95% Na₂O) and PG’s sulfate activation. Collectively, these approaches reduced landfill reliance by 50% and CO₂ emissions by 35%–40% compared to conventional practices. The results demonstrate RM’s potential as a secondary resource, offering economically viable and environmentally sustainable pathways for the alumina industry. Full article

This study investigates graphite separation from Lithium-Ion Battery (LIB) black mass (which is a mixture of anode and cathode materials) via froth flotation coupled with an open-loop recycling approach for the graphite (froth) product. Black mass samples originating from different LIB types were used to produce a carbon-poor and a carbon-enriched fractions. The optimization of the flotation parameters was carried out depending on the black mass chemistry, i.e., the number of flotation stages and the dosing of flotation agents. The carbon-enriched product (with a carbon content of 92 wt.%, corresponding to a recovery of 89%) was subsequently used as a secondary carbon source for refractory material (magnesia carbon brick). Analyses of brick chemistry, as well as thermo-mechanic properties in terms of density, porosity, cold crushing strength (CCS), hot modulus of rupture (HMOR—the maximum bending stress that can be applied to a material before it breaks), and thermal conductivity showed no negative influence on brick quality. It could be demonstrated that flotation graphite can principally be used as a secondary source for non-battery applications. This is a highly valuable example that contributes to a more complete closure of a battery’s life cycle in terms of circular economy. Full article

Luminescence techniques, especially thermoluminescence (TL) and optically stimulated luminescence (OSL), are essential for dating materials in Cultural Heritage. TL is effective for dating bricks by determining their last heating event, but brick reuse can introduce inaccuracies. OSL enhances accuracy by dating the last light exposure of quartz grains in mortars, a material that is coeval with the construction of the building. However, partial bleaching of quartz grains can lead to overestimated ages. A promising solution involves dating the carbonate fraction of mortars, as calcium carbonate experiences bleaching during mortar preparation. This study investigates the feasibility of isolating signals from quartz and calcite in a composite material. Initially, TL signals for quartz and calcite were characterized separately. A laboratory mixture, comprising 75% quartz and 25% calcite, was irradiated to simulate partial bleaching. TL curve deconvolution revealed distinct peaks: quartz displayed four peaks, while calcite had three, notably lacking a low-temperature peak. The mixed sample exhibited peaks at 527 K, 573 K, 618 K, and 690 K, with the first peak being exclusively quartz, the second primarily quartz with minor calcite, and the third showing contributions from both. Dose-response curves indicated that the quartz peaks aligned with the expected 41.40 Gy dose, and the calcite signal matched 10.40 Gy. This confirms the feasibility of separating TL signals from quartz and calcite in mixed samples, offering a potential method for accurately dating the carbonate fraction in mortars and addressing partial bleaching issues. Future work will focus on optimizing detection parameters and applying this method to historically significant mortars to assess its effectiveness. Full article

The reaction in reagent grade acetone of copper(II) nitrate hexahydrate, 2,2′-bipyrimidine (bpm) and potassium iodide in a 1:2:2 molar ratio afforded three different products: an unreduced Cu(II) species, a fully reduced Cu(I) species and a mixed-valent Cu(II)/Cu(I) species. Of these, only the unreduced Cu(II) complex of formula [Cu^II(bpm)₃](I₃)(I) (1) could be structurally characterized, the other two products being initially only isolated as amorphous powders. X-ray quality, beautifully shaped, quasi-black prismatic crystals of compound 2, namely {[Cu^I(I₃)Cu^II(I)(bpm)₂](I₃)}_n, and brick-reddish parallelepipeds of compound 3, namely {[Cu^I₂ (μ-I)₂(bpm)]}_n, were successively obtained through the slow diffusion in H-shaped tubes of aqueous solutions of the three reagents, after extensive optimization of the crystallization conditions. Compound 1 consists of a rare tris(2,2′-bipyrimidine)copper(II) monomeric dication, charge balanced by both iodide and triiodide anions. Compound 3, whose structure as well as optical and photocatalytic properties were recently disclosed, consists of a regular alternating μ-bpm/di-μ-iodide copper(I) chain. Finally, compound 2 consists of a rare, regular alternating mixed-valent Cu(II)-Cu(I) μ-bpm copper chain, showing unusual similarities in the metal coordination environment. The magnetic properties of compound 2 remarkably reveal a very weak antiferromagnetic coupling between the paramagnetic Cu(II) ions which are well separated both intra- and inter-chain. Full article

Geopolymer technology is considered a strategic alternative for recycling construction and demolition waste (CDW) and to produce new construction products which meet the requirements of environmental and energy sustainability. The separation and management of CDW fractions is still a technological complex process and, even if large-scale separation technology is quite common, the necessity to perform this treatment may reduce the environmental and economic benefits of CDW reuse. So, a very promising option is represented by the manufacturing of geopolymers using unseparated CDW. In this aim, waste deriving from cement-based mortars, bricks and natural stones have been selected and widely characterized from a mineralogical, chemical and morphological point of view. Then, geopolymer mortars were produced using several amounts of either a single fraction or a mixture of the selected waste. The chemical, physical, mechanical, and microstructural characterization of the geopolymer-produced mortars was carried out to assess how the combination and different quantities of the mixed CDW affected the final properties. In particular, geopolymeric mortars produced from the unselected CDW showed higher mechanical properties, despite the lower apparent density, when compared to geopolymeric mortars produced from single fractions of CDW. The improvement of mechanical features seems to be not affected by the waste amount used, providing encouraging findings to promote the actual use of unseparated CDW with the resulting enhancement of environmental and economic benefits. Full article

Customer context analysis (CCA) in brick-and-mortar shopping malls can support decision makers’ marketing decisions by providing them with information about customer interest and purchases from merchants. It makes offline CCA an important topic in marketing. In order to analyze customer context, it is necessary to analyze customer behavior, as well as to obtain the customer’s location, and we propose an analysis system for customer context based on these two aspects. For customer behavior, we use a modeling approach based on the time-frequency domain, while separately identifying movement-related behaviors (MB) and semantic-related behaviors (SB), where MB are used to assist in localization and the positioning result are used to assist semantic-related behavior recognition, further realizing CCA generation. For customer locations, we use a deep-learning-based pedestrian dead reckoning (DPDR) method combined with a node map to achieve store-level pedestrian autonomous positioning, where the DPDR is assisted by simple behaviors. Full article

In Poland, two species of the genus Anagallis can be found in segetal communities: scarlet pimpernel (Anagallis arvensis L.) and blue pimpernel (Anagallis foemina Mill.). A. arvensis usually has brick-red flowers and is a common weed in arable crops. Meanwhile, A. foemina, with blue flowers, is considered a species at risk of extinction in Poland. Flower colour is not a determinant of species affiliation, as there is a form of Anagallis arvensis f. azurea with blue flowers; thus, it is very difficult to specify the species identity of plants with blue flowers based on the negligible differences in morphology. Therefore, for the determination of species affiliation, the presence of two deletions within the intron of the chloroplastic gene trnL in A. arvensis and their absence in A. foemina were confirmed. The genetic similarity and population structure were established based on DNA polymorphism markers identified via the ISSR (inter simple sequence repeat) and SRAP (sequence-related amplified polymorphism) methods. UPGMA (unweighted pair group method with arithmetic mean) analyses revealed that red-flowered (A. arvensis) and blue-flowered (A. foemina) plants were grouped into two separate groups. Within the A. foemina group, two subgroups were distinguished: the first subgroup included genotypes from the Lublin Upland (LU) and Volhynian Polesie (VP), while the second subgroup consisted of genotypes from Western Volhynian Upland (VU). The within-group genetic diversity of A. arvensis was greater than the diversity within the A. foemina subpopulations. Principal coordinate analysis (PCoA) and STRUCTURE were also used to group samples according to species affiliation and collection site. The results obtained confirm that A. foemina populations in the study area are fragmented and isolated, which may lead to a decrease in their adaptability to environmental changes, reduced reproductive rates, and increased mortality. Full article

Nacre has excellent balanced strength and toughness. In this paper, the mechanical performance of the typical “brick-and-mortar” structure, including the stress–strain and strain at the interface as well as the stress in the bricks, was calculated by a simplified analytical model of the nacre. This paper proposes a new method to control the crack deflection based on the toughening mechanism of the nacre. The crack extension of the “brick-and-mortar” structure was simulated using cohesive elements based on the traction–separation law with elastic and softening stiffness as variables, and it was found that both stiffness could effectively control the crack extension. The strength and toughness of the models with different stiffness combinations were calculated and plotted as a function of elastic stiffness and softening stiffness, showing that elastic stiffness significantly affects strength and softening stiffness is a determinant of toughness. Full article

Excessive consumption of natural resources to meet the growing demands of building and infrastructure projects has put enormous stress on these resources. On the other hand, a significant quantity of soil is excavated for development activities across the globe and is usually treated as waste material. This study explores the potential of excavated soils in the Brittany region of France for its reuse as earthen construction materials. Characterization of soil recovered from building sites was carried out to classify the soils and observe their suitability for earthen construction materials. These characteristics include mainly Atterberg limits, granulometry, organic matter and optimum moisture content. Soil samples were separated into fine and coarse particles through wet sieving. The percentage of fines (particles smaller than 0.063 mm) in studied soil samples range from 28% to 65%. The methylene blue value (MBV) for Lorient, Bruz and Polama soils is 1, 1.2 and 1.2 g/100 g, and French classification (Guide de terrassements des remblais et des couches de forme; GTR) of soil samples is A1, B5 and A1, respectively. The washing of soils with lower fine content helps to recover excellent-quality sand and gravel, which are a useful and precious resource. However, residual fine particles are a waste material. In this study, three soil formulations were used for manufacturing earth blocks. These formulations include raw soil, fines and restructured soil. In restructured soil, a fine fraction of soil smaller than 0.063 mm was mixed with 15% recycled sand. Restructuring of soil fine particles helps to improve soil matrix composition and suitability for earth bricks. Compressed-earth blocks of 4 × 4 × 16 cm were manufactured at a laboratory scale for flexural strength testing by using optimum molding moisture content and compaction through Proctor normal energy. Compressive strength tests were performed on cubic blocks of size 4 × 4 × 4 cm. Mechanical testing of bricks showed that bricks with raw soil had higher resistance with a maximum of 3.4 MPa for Lorient soil. Removal of coarse particles from soil decreased the strength of bricks considerably. Restructuring of fines with recycled sand improves their granular skeleton and increases the compressive strength and durability of bricks. Full article

Nanostructured lipid carriers (NLCs) are typically composed of liquid lipids, solid lipids, and surfactants, enabling the encapsulation of lipophilic drugs. Butamben is a Class II anesthetic drug, according to the Biopharmaceutical Classification System (BCS); it has a log P of 2.87 and is considered a ‘brick dust’ (poorly water-soluble and poorly lipid-soluble) drug. This characteristic poses a challenge for the development of NLCs, as they are not soluble in the liquid lipid present in the NLC core. In a previous study, we developed an NLC core consisting of a solid lipid (Crodamol^TM CP), a lipophilic liquid with medium polarity (SR^TM Lauryl lactate), and a hydrophilic excipient (SR^TM DMI) that allowed the solubilization of ‘brick dust’ types of drugs, including butamben. In this study, starting from the NLC core formulation previously developed we carried out an optimization of the surfactant system and evaluated their performance in aqueous medium. Three different surfactants (Crodasol^TM HS HP, Synperonic^TM PE/F68, and Croduret^TM 40) were studied and, for each of them, a 2³ factorial design was stablished, with total lipids, % surfactant, and sonication time (min) as the input variables and particle size (nm), polydispersity index (PDI), and zeta potential (mV) as the response variables. Stable NLCs were obtained using Crodasol^TM HS HP and Synperonic^TM PE/F68 as surfactants. Through a comparison between NLCs developed with and without SR^TM DMI, it was observed that besides helping the solubilization of butamben in the NLC core, this excipient helped in stabilizing the system and decreasing particle size. NLCs containing Crodasol^TM HS HP and Synperonic^TM PE/F68 presented particle size values in the nanometric scale, PDI values lower than 0.3, and zeta potentials above |10|mV. Concerning NLCs’ stability, SBTB-NLC with Synperonic^TM PE/F68 and butamben demonstrated stability over a 3-month period in aqueous medium. The remaining NLCs showed phase separation or precipitation during the 3-month analysis. Nevertheless, these formulations could be freeze-dried after preparation, which would avoid precipitation in an aqueous medium. Full article

In the present study, we investigated the mechanical performance of concrete composed of non-selected construction and demolition waste (C&DW) sourced from both old and new sections of an inactive waste landfill site in Karaj, Iran. Initially, we determined the composition of the coarse and fine C&DW used in concrete production. Subsequently, we meticulously examined the physical and chemical properties of both the C&DW and virgin materials to enable thorough comparisons of the results. We then conducted experimental analyses on 33 concrete mixtures containing recycled C&DW, utilizing various tests, including a compressive strength test (CST) for cylindrical and cubic samples, modulus of elasticity (MOE), wide wheel abrasion test (Capon test), British pendulum number (BPN), and ultrasonic pulse velocity (UPV) test. We considered both non-separated fine and coarse C&DW at different replacement ratios in the recycled concrete (RC). Our findings indicate that using non-separated coarse and fine C&DW in concrete yielded satisfactory results, leading to significant savings in virgin materials required for concrete preparation and promoting sustainable development. Furthermore, non-selected C&DW proved to be a viable sustainable material for similar concrete applications. The results revealed a decrease in brick material consumption in various constructions over the past 20 years in Karaj, contributing to the enhanced strength of C&DW concrete. However, the presence of clay minerals in aged landfill sites can adversely affect concrete performance as a potential destructive factor. Despite the possible negative impact of incorporating fine recycled C&DW materials on concrete mechanical performance, the Capon test results demonstrated that the presence of coarse C&DW can enhance concrete’s wear resistance. Full article

Weathered granite contains a high concentration of feldspar, quartz, and kaolin. However, while it becomes rich in clay due to strong physical weathering, the granite minerals that are not fully weathered are still very hard, which makes the grinding process more difficult and limits its use. This study proposes a multi-step process involving grinding, desliming, and flotation to address this issue. The study determines the appropriate grinding time and power index for the original ore, as well as the optimal desliming method using a hydrocyclone. To remove iron-containing impurities like mica, a combination of NaOL/BHA/A CO collectors is used for the reverse rough flotation of quartz. Additionally, a combination of DDA/SDS collectors is employed to separate quartz and feldspar through flotation, resulting in a quartz product with a silicon dioxide content of 99.51%. The objective of efficiently recycling feldspar, quartz, and kaolin from weathered granite is accomplished. Additionally, the inclusion of intermediate mineral components as by-products of feldspar and raw materials for aerated bricks is introduced, resulting in the complete utilization of all components. This innovative approach ensures a clean and environmentally friendly process, eliminating the need for solid waste disposal. Full article

The European Union (EU) is responsible for generating quantities ranging from 310 to almost 700 million tons of construction and demolition waste (CDW) per year. Consisting of over 70% inert material (concrete, ceramics, plaster, bricks, and rocks), CDW can be recycled for various uses, and studies on the concentration of the materials of interest are necessary to improve the management of this material and reduce waste. In CDW recycling plants in Spain, there is a significant presence of limestone from old houses (a common material used in civil construction before new construction materials and technologies emerged) that were demolished and mixed with CDW that can be recovered for use as aggregates in concretes with process density concentration processes such as water jigging. The jigging process is based on the difference in density between materials, allowing the concentration of the densest material at the bottom of the jig. Concrete, conventional construction bricks, and rocks from old houses were taken separately and then were crushed and mixed based on binary and ternary tests, and each test was performed in this study by applying the jigging separation method. The physical characterization tests of these materials was carried out to observe the jigging performance in the concentration of rocks as well as the aggregates present in concrete. Binary tests (with two different materials) and ternary tests (with three different materials) were carried out to analyze the concentration of particles with a density greater than 2.55 g/cm³. The efficiency of jigging in the concentration of these materials was proven, and products were generated with more than 70% recovery of this material, with a concentration comprised of more than 95% rocks and concrete. Full article

Each year, an enormous amount of construction waste is produced worldwide. The reuse of construction waste in construction works is a sustainable solution. The present research work utilized recycled brick aggregates in the production of concrete. The resulting concrete exhibited substandard splitting tensile, flexural, and compressive properties. Steel fibers were used to improve these substandard properties of recycled brick aggregate concrete. The volume fractions of 1%, 2%, and 3% for steel fibers were mixed in concrete, whereas recycled brick aggregates were obtained from solid fired-clay bricks, hollow fired-clay bricks, and cement–clay interlocking bricks. The compressive strength was enhanced by up to 35.53% and 66.67% for natural and recycled brick aggregate concrete, respectively. Strengthened flexural specimens demonstrated up to 8765.69% increase in the energy dissipation. Specimens strengthened with steel fibers showed substantially improved splitting tensile, flexural, and compressive responses. Separate equations were proposed to predict the peak compressive strength, strain at peak compressive strength, elastic modulus, and post-peak modulus of recycled brick aggregate concrete. The proposed regression equations were utilized in combination with an existing compressive stress–strain model. A close agreement was observed between experimental and predicted compressive stress–strain curves of recycled brick aggregate concrete. Full article