Expansive soils pose a significant challenge to civil infrastructure due to their high potential for expansion and contraction. These soils exhibit poor mechanical properties, leading to severe structural damage and high maintenance costs. To address these challenges, conventional stabilization like cement or lime, are widely used; however, their production substantially increases global carbon dioxide emissions and energy requirements. Therefore, there is an urgent need to develop sustainable alternatives that enhance soil performance while minimizing environmental impact by utilizing industrial by-products. In response to this need, this study proposes a sustainable composite reinforcement scheme that combines enzyme-induced carbonate precipitation (EICP), sisal fiber (SFs) reinforcement, and iron ore tailings (IOts) to treat expansive soil by deploying laboratory testing and response surface modeling (RSM). Utilizing the experimental and validated optimal mix (0.75 mol/L EICP + 0.53 % SFs + 11.7 % IOts) reduced swelling pressure ∼98 % while increasing the unconfined compressive strength ∼262 %, cohesion ∼78 %, the angle of internal friction ∼172 %, Unsoaked California Bearing Ratio (CBRunsoak) from 2.4 % to ∼26 % and CBRsoak 1.7 % to ∼20 % after 28 days curing. In addition, SEM and EDS analyses confirmed synergistic microstructural interactions, resulting in a highly reinforced soil composite. Moreover, the RSM model showed good agreement with the experimental results, with errors controlled within ±5 %, validating the robustness of the model. By reusing mining waste and utilizing renewable fibers, this approach demonstrates a low-carbon, cost-effective, and scalable stabilization strategy that enhances infrastructure resilience and promotes circular economy objectives.
Materials of engineering and construction. Mechanics of materials
In areas as diverse as contemporary art, play structures, climbing equipment, and modular construction toys, we see the presence of building block-like polyhedral complexes, which are generalizations of the pieces in the game Tetris. We give an algorithm for counting the number of $n$-celled structures on polygonal and polyhedral cells of certain periodic two- and three-dimensional tilings; moreover, we count these structures up to translations, rotations, and reflections of the tiling. We describe this algorithm with respect to structures in the snub square tiling, provide numerical data related to existing three-dimensional art and structures, and suggest puzzles based on these constructions.
Abstract Building Information Modelling (BIM) constitutes the state of the art in the digital design techniques, and represents one of the main streams of the Industry 4.0 era. The integration of BIM into processes related to buildings design, construction and operation is a practice in line with the sustainability aspects of the built environment, and which gains more interest in the recent years in the field of research development. This study aspires to present the main advancements in the field of building integration modelling in the field of smart buildings. Emphasis is given on the integration of IoT applications into buildings smart operations. The study is structured in four sections, concerning the use of BIM in pre-, during- and post-construction life cycles of the project, as well as for other significant aspects. In the pre-construction stage, research trends in the field of building design and optimization, as well as for the environmental assessment of buildings’ design with the use of BIM and LCA tools is presented. Issues related to the use of BIM for monitoring and coordination during construction, as well as for health and safety topics in the construction site are also analysed. An overview of recent studies in the area of applications for buildings smart operation with the use of IoT technologies, as well as for renovation projects, are considered in the analysis of the post-construction applications of BIM. Interoperability issues concerning data sharing between BIM related applications is presented, according to the recent advancements in standardization processes.
Determining the transmission routes of pathogens in indoor environments is challenging, with most studies limited to specific case analyses and pilot experiments. When pathogens are instantaneously released by a patient in an indoor environment, the peak infection risk may not occur immediately but may instead appear at a specific moment during the pathogen’s spread. We developed a concise model to describe the temporal crest of infection risk. The model incorporates the transmission and degradation characteristics of aerosols and surface particles to predict infection risks via air and surface routes. Only four real-world outbreaks met the criteria for validating this phenomenon. Based on the available data, norovirus is likely to transmit primarily via surface touch (i.e., the fomite route). In contrast, crests of infection risk were not observed in outbreaks of respiratory diseases (e.g., SARS-CoV-2), suggesting a minimal probability of surface transmission in such cases. The new model can serve as a preliminary indicator for identifying different indoor pathogen transmission routes (e.g., food, air, or fomite). Further analyses of pathogens’ transmission routes require additional evidence.
The vertical load-bearing performance of slab–column joints is significantly affected by bottom reinforcement and concealed beams, but existing studies remain insufficient in analyzing their influence mechanisms. To address this, the effects of bottom reinforcement, concealed beam width, and punch-to-span ratio on the mechanical properties of joints are systematically investigated in this study through finite element analysis. Validating 2 experimental models and establishing 13 parametric models, the results shows that adding bottom reinforcement can enhance the late-stage bearing capacity and ductility of joints; increasing the ratio of top-to-bottom reinforcement improves bearing capacity but reduces ductility; a wider concealed beam leads to better bearing capacity and ductility performance of the joint; and under the same concealed beam width, a larger punching–span ratio reduces bearing capacity but improves ductility. This study reveals the critical role of bottom reinforcement and concealed beams in joint performance, providing a theoretical basis for optimizing design.
Najeeb Manhanpally, Praveen Nagarajan, Suman Saha
et al.
Abstract In search of sustainable construction material as an alternative to existing ordinary cement concrete, the use of recycled aggregates in geopolymer concrete has garnered significant attention. Using industrial by-products such as dolomite and ground granulated blast furnace slag (GGBS), combined with alkali activators like sodium silicate and sodium hydroxide to prepare geopolymer concrete, offers a promising substitute to traditional Portland cement concrete. This study explores the potential of incorporating recycled aggregates, specifically focusing on the benefits of treated recycled-aggregates (TRCA) into the concrete for improving sustainability of geopolymer concrete. Mechanical grinding treatment is found to be effective in removing adhered mortar from recycled-aggregates, and thus improving aggregate quality and reducing porosity and micro-cracks. By systematically analyzing the effects of untreated and treated recycled aggregates on concrete properties, this research provides a comprehensive understanding of how treatment processes can mitigate the limitations of RCA and optimize the material’s performance. Incorporating treated recycled aggregates enables the construction industry to adopt more sustainable building practices, thus helping global efforts to minimise damages to the environment. The experimental results demonstrated that treating recycled aggregates showed key engineering properties of geopolymer concrete similar to normal geopolymer concrete with reduction less than 5% at 100% replacement level. Geopolymer concrete, made from GGBS and dolomite with treated recycled aggregates, provides a sustainable substitute for conventional concrete, offering environmental and structural advantages. This paper promotes the use of treated recycled aggregates to decrease the dependency on natural resources, therefore promoting the circular economy within the building industry. The findings of this study are expected to advance the knowledge of recycled aggregate utilization in geopolymer concrete, offering practical insights for construction professionals and researchers. The research seeks to develop novel, sustainable, and high-performance construction materials that meet environmental and structural requirements.
Recently, recycling of waste vehicle tyres which pose a significant risk to environmental health has become an important research issue due to environmental concerns worldwide. To handle the waste tyre pollution problem, recycling waste into new products and using waste to improve other materials’ properties can be considered. Waste vehicle tyres can be used in the production of energy and various materials, providing economic and environmental advantages. In this study, experimental studies were carried out on the use of waste tyre steel fiber (WS) obtained from the recycling of heavy vehicle tyres in concrete, including the goal of recycling and reducing the need for raw materials. In one experimental group, waste tyre steel was added to concrete at 0.4% by volume instead of fine aggregate, while in the other experimental group it was added at 0.8% by volume. In the study, in addition to mechanical analyses, many microanalysis experiments were carried out to understand whether there was a strong relationship between the results. The study was conducted at target temperatures of 400, 600 and 800 °C depending on the fire scenario for building and construction materials according to ISO 834 and ASTM E119 standards. Compressive strength losses and characterization changes in 15 cm cube plain concrete and composite concrete specimens exposed to targeted high temperatures for 60 minutes were compared in terms of strength. Ultrasonic pulse velocity (UPV), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential thermal analysis (DTA), X-ray diffraction analysis (XRD) and Fourier transform infrared spectroscopy (FTIR) analysis was also performed, as it was understood that there was not enough data in the literature regarding waste tyre steel fiber reinforced concrete. General results showed that fiber-added concrete made significant contributions to concrete performance at high temperatures.
Materials of engineering and construction. Mechanics of materials
The brittle fracture and toughness of cemented tailings backfill (CTB) are not conducive to underground mining projects. Incorporating fibers may enhance the flexural properties of the CTB. This study used glass (GS) and polypropylene (PP) fibers to fabricate fiber-reinforced cemented lithium feldspar tailing backfill (FCLTB) specimens. The flexural strengths and microstructures of the specimens were analyzed using a three-point flexure test and scanned electron microscopy (SEM). Following a three-point bending test, it was observed that Upon decreasing the amount of GS fiber, the bending strength of the FCLTB specimens initially decreased and then increased. However, with an increase in the PP fiber content, the average bending module of the FCLTB specimens initially reduced and then rose. The combined use of GS and PP fibers significantly improved the toughness of the CLTB samples after the peak. Composite fibers resist the formation of cracks under load.
Engineering (General). Civil engineering (General), Building construction