Search Results (82)

The construction sector, particularly the production of materials like cement and steel, is a major contributor to global CO₂ emissions, with cement alone responsible for about 8%. Conventional masonry relies heavily on cement, increasing embodied carbon and costs, but standardized data on low-carbon alternatives such as compressed stabilized earth blocks (CSEBs) remain scarce, limiting their adoption in sustainable housing. To support the United Nations Environment Program (UNEP) and the Paris Agreement goals for net-zero embodied carbon in building materials by 2050, this study aims to assess the production and performance of CSEBs as a low carbon alternative to conventional masonry. It specifically addresses the research gap on technical performance and carbon savings, providing new empirical evidence for Ethiopian soils. Soil samples from Kara (east of Addis Ababa) were analyzed for grading, plasticity, and chemical composition. Blocks were produced with Portland pozzolana cement (4–12%) under compaction pressures of 4–10 MPa and tested for compressive strength and water absorption over 56 days. Results show that 6% cement content achieved >2 MPa compressive strength, meeting the structural requirements, while higher cement content and pressure improved strength and reduced absorption. Compared to hollow concrete blocks, CSEBs cut cement use by over 50%, avoiding up to 2 tons of CO₂ per 100 m² of wall. These findings confirm CSEBs as a technically viable and climate-conscious solution for affordable housing and support their integration into sustainable construction practices. Full article

Structure detection (SD) has emerged as a critical technology for ensuring the safety and longevity of infrastructure, particularly in housing and civil engineering. Traditional SD methods often rely on manual inspections, which are time-consuming, labor-intensive, and prone to human error, especially in complex environments such as dense urban settings or aging buildings with deteriorated materials. Recent advances in autonomous systems—such as Unmanned Aerial Vehicles (UAVs) and climbing robots—have shown promise in addressing these limitations by enabling efficient, real-time data collection. However, challenges persist in accurately detecting and analyzing structural defects (e.g., masonry cracks, concrete spalling) amidst cluttered backgrounds, hardware constraints, and the need for multi-scale feature integration. The integration of machine learning (ML) and deep learning (DL) has revolutionized SD by enabling automated feature extraction and robust defect recognition. For instance, RepConv architectures have been widely adopted for multi-scale object detection, while attention mechanisms like TAM (Technology Acceptance Model) have improved spatial feature fusion in complex scenes. Nevertheless, existing works often focus on singular sensing modalities (e.g., UAVs alone) or neglect the fusion of complementary data streams (e.g., ground-based robot imagery) to enhance detection accuracy. Furthermore, computational redundancy in multi-scale processing and inconsistent bounding box regression in detection frameworks remain underexplored. This study addresses these gaps by proposing a generalized safety inspection system that synergizes UAV and stair-climbing robot data. We introduce a novel multi-scale targeted feature extraction path (Rep-FasterNet TAM block) to unify automated RepConv-based feature refinement with dynamic-scale fusion, reducing computational overhead while preserving critical structural details. For detection, we combine traditional methods with remote sensor fusion to mitigate feature loss during image upsampling/downsampling, supported by a structural model GIOU [Mathematical Definition: GIOU = IOU − (C − U)/C] that enhances bounding box regression through shape/scale-aware constraints and real-time analysis. By siting our work within the context of recent reviews on ML/DL for SD, we demonstrate how our hybrid approach bridges the gap between autonomous inspection hardware and AI-driven defect analysis, offering a scalable solution for large-scale housing safety assessments. In response to challenges in detecting objects accurately during housing safety assessments—including large/dense objects, complex backgrounds, and hardware limitations—we propose a generalized inspection system leveraging data from UAVs and stair-climbing robots. To address multi-scale feature extraction inefficiencies, we design a Rep-FasterNet TAM block that integrates RepConv for automated feature refinement and a multi-scale attention module to enhance spatial feature consistency. For detection, we combine dynamic-scale remote feature fusion with traditional methods, supported by a structural GIOU model that improves bounding box regression through shape/scale constraints and real-time analysis. Experiments demonstrate that our system increases masonry/concrete assessment accuracy by 11.6% and 20.9%, respectively, while reducing manual drawing restoration workload by 16.54%. This validates the effectiveness of our hybrid approach in unifying autonomous inspection hardware with AI-driven analysis, offering a scalable solution for SD in housing infrastructure. Full article

Pakistan’s housing sector faces a significant shortfall alongside growing climate risks. This study assesses climate-smart construction options autoclaved aerated concrete (AAC) blocks, interlocking bricks, and rat-trap bond masonry through energy simulations, cost modeling, and expert consultations. A 10-Marla residential unit in Islamabad was used as the reference case. Results indicate AAC reduces cooling energy by 22%, interlocking bricks reduce construction costs by 26.6%, and rat-trap masonry lowers electricity use by 12–16%. Despite technical viability, adoption remains limited due to financing and regulatory barriers. The study proposes a phased policy roadmap to integrate low-carbon materials into Pakistan’s housing and climate adaptation strategies. Full article

This study investigates the potential of corn stover, an abundant agricultural byproduct, as a sustainable additive in concrete masonry units (CMUs). Preliminary trials were conducted to determine the optimal fiber length (~3 mm and ~10 mm), fiber content (0%, 1%, 3%, and 5% by volume), and alkalinization method (soaking in 0.5 M NaOH, KOH, or synthetic concrete pore solution) for corn stover fibers (CSFs). The results indicated that short fibers treated with synthetic concrete pore solution yielded the best compressive strength and workability, and were thus selected for the main study. A novel mixture was developed by replacing 10% of cement with corn stover ash (CSA) and incorporating 1% alkaline-treated CSF by volume. The resulting blocks (termed “Corncrete”) were evaluated for mechanical and durability properties, including strength, water absorption, bulk and surface electrical resistivity, rapid chloride permeability (RCPT), and fire resistance. Compared to conventional CMUs, Corncrete exhibited an 11–13% reduction in 28- and 91-day compressive strength, though the difference was statistically insignificant. Physically, Corncrete had a 4.4% lower bulk density and a 7.9% higher total water absorption compared to the control. However, its water absorption rates at early stages were 32% and 48% lower, indicating better resistance to moisture uptake shortly after exposure. Durability tests revealed a 13.7% reduction in chloride ion permeability and a 33% increase in bulk and surface electrical resistivity after 90 days. Fire performance was comparable between the two mixtures, with both displaying ~10.5% mass loss and ~5% residual strength after high-temperature exposure. These findings demonstrate that Corncrete offers balanced mechanical performance and enhanced durability, making it a viable eco-friendly option for non-structural masonry applications. Full article

To enhance the utilization efficiency of coal gangue aggregate, coarse aggregates are chemically modified with 5% sodium silicate solution. The effects of this modification on the compressive strength and microstructural characteristics of concrete are systematically investigated through integrated macro-testing and micro-characterization. By evaluating the compressive performance of modified coal gangue concrete blocks, the optimal mix ratio of each strength grade of blocks is determined. Experimental results indicate that the apparent density, water absorption, and crushing index of the modified coal gangue coarse aggregate exhibit better mechanical properties than the control group. The modified coal gangue coarse aggregate demonstrates improved mechanical performance, with the compressive strength of 28-day concrete showing a 15.3% increase relative to the control group. Furthermore, using a sodium silicate solution effectively enhances the interface transition zone’s performance between coal gangue coarse aggregate and cement mortar, improving the compactness of this interface. The modified coal gangue concrete blocks exhibit higher compressive strength than the original material. When the substitution rate remains constant, the compressive strength of modified coal gangue concrete decreases with increasing water–cement ratio. Similarly, at a constant water–binder ratio, compressive strength decreases with higher modified gangue aggregate replacement. Finally, compressive tests are conducted on masonry constructed with hollow blocks of strength grades MU7.5, MU10, and MU15. Then, a calculation model for the average compressive strength of modified coal gangue concrete hollow block masonry is proposed, providing theoretical support for its engineering application. Full article

The use of single-layer aerated concrete walls in residential construction has a tradition of over 60 years. Its main advantage is thermal insulation. It is the most advantageous among construction materials used for the construction of external walls. The possibility of modifying the dimensions of the blocks leads to meeting subsequent restrictive values of the heat transfer coefficient U. The high dimensional accuracy of the blocks allows the use of dry vertical joints and thin joints with a thickness of 1–3 mm, the thermal influence of which is omitted. However, the thermal uniformity of such a wall is strictly dependent on the quality of workmanship. The main objective of the analysis is to assess the impact of moisture on the U_wall of walls as a function of vertical joint spacing and horizontal joint thickness. It should be said that the effect of humidity and manufacturing accuracy on the thermal properties of aerated concrete walls has not been sufficiently studied. Further study of these patterns is necessary. Particular attention should be paid to the thin-bed mortar, which depends on the manufacturing accuracy. The separation of AAC masonry elements that occurs during bricklaying significantly affects the thermal insulation of walls. This issue has not yet been analysed. The scientific objective of this article is to develop a procedure for determining the thermal properties of a small, irregular air space created as a result of the separation of masonry elements and the impact of this separation on the thermal insulation of the wall. Based on the analysis of the thermal conductivity of voids and masonry elements, it was determined that this impact is visible at low AAC densities. A detailed analysis taking into account both these joints and horizontal joints, as well as different moisture levels, made it possible to determine the permissible separation of AAC blocks, at which the high thermal insulation requirements applicable in most European countries are met. The analysis showed that it is possible to meet the thermal protection requirements for 42 cm wide blocks intended for single-layer walls with a maximum vertical contact width of 3 mm and a joint thickness of up to 2 mm. AAC moisture content plays a major role in thermal insulation. Insulation requirements can be met for AAC in an air-dry state, as specified by ISO 10456. Full article

In this study, an effective strengthening method was investigated to improve the seismic performance of masonry brick walls. The strengthening method comprised the use of shotcrete, which was applied in both glass fiber-reinforced and unreinforced forms for steel plates and tie rods. Thirteen wall specimens constructed with vertical perforated masonry block bricks were tested under diagonal compression in accordance with ASTM E519 (2010). Reinforcement plates with different thicknesses (1.5 mm, 2 mm, and 3 mm) were anchored using 6 mm diameter tie rods. A specially designed steel frame and an experimental loading program with controlled deformation increments were employed to simulate the effects of reinforced concrete beam frame system on walls under the effect of diagonal loads caused by seismic loads. In addition, numerical simulations were conducted using three-dimensional finite element models in Abaqus Explicit software to validate the experimental results. The findings demonstrated that increasing the number of tie rods enhanced the shear strength and overall behavior of the walls. Steel plates effectively absorbed tensile stresses and limited crack propagation, while the fiber reinforcement in the shotcrete further improved wall strength and ductility. Overall, the proposed strengthening techniques provided significant improvements in the seismic resistance and energy absorption capacity of masonry walls, offering practical and reliable solutions to enhance the safety and durability of existing masonry structures. Full article

This study investigates the bond behavior of fabric-reinforced cementitious matrix (FRCM) composites with three common masonry substrates—solid clay bricks (SBs), perforated bricks (PBs), and concrete hollow blocks (HBs)—using knitted polyester grille (KPG) fabric. Through uniaxial tensile tests of the KPG fabric and FRCM system, along with single-lap and double-lap shear tests, the interfacial debonding modes, load-slip responses, and composite utilization ratio were evaluated. Key findings reveal that (i) SB and HB substrates predominantly exhibited fabric slippage (FS) or matrix–fabric (MF) debonding, while PB substrates consistently failed at the matrix–substrate (MS) interface, due to their smooth surface texture. (ii) Prism specimens with mortar joints showed enhanced interfacial friction, leading to higher load fluctuations compared to brick units. PB substrates demonstrated the lowest peak stress (69.64–74.33 MPa), while SB and HB achieved comparable peak stresses (133.91–155.95 MPa). (iii) The FRCM system only achieved a utilization rate of 12–30% in fabric and reinforcement systems. The debonding failure at the matrix–substrate interface is one of the reasons that cannot be ignored, and exploring methods to improve the bonding performance between the matrix–substrate interface is the next research direction. HB bricks have excellent bonding properties, and it is recommended to prioritize their use in retrofit applications, followed by SB bricks. These findings provide insights into optimizing the application of FRCM reinforcement systems in masonry structures. Full article

Polymer residues can be reused in civil construction by partially replacing mineral aggregates in concrete, thereby reducing the extraction of natural resources. This study aimed to evaluate the use of powdered poly (ethylene terephthalate) (PET) and polyethylene (PE) residues, accumulated in shaving-mill filters during the extrusion of multilayer films used in food packaging, in the production of sealing masonry blocks. The PET/PE residues were characterized by Fourier Transform Infrared Spectroscopy (FTIR), thermogravimetric analysis (TGA) and scanning electron microscopy (SEM). Cylindrical specimens were produced in which part of the sand, by volume, was replaced with 10, 20, 30, 40 and 50% polymer residue. The cylindrical specimens were evaluated for specific mass, water absorption and axial and diametral compressive strengths. The 10% content provided the highest compressive strength. This formulation was selected for the manufacture of concrete blocks, which were evaluated and compared with the specifications of ABNT NBR 6136:2014. The concrete blocks showed potential for applications without structural function and were classified as Class C. The results, in line with previous investigations on the incorporation of plastic waste in concrete, underscore the promising application potential of this strategy. Full article

This paper presents a study on the uniaxial compressive behavior of fully grouted concrete bond beam block masonry prisms. A total of 45 (i.e., 9 hollow and 36 fully grouted) specimens were tested, and the failure modes and initial crack were reported. The effects of block strength, grout strength, and loading scheme on the compressive strength of the fully grouted prism were discussed. The results show that the compressive strength of bond beam block prisms increased with an increase in grouting, while they were less affected by the block strength; the peak strength of the grouted block masonry was, on average, 35.1% higher than the hollow masonry prism. In addition, although the specimens’ strength was lower under cyclic compression than under monotonic compression loading, the difference in their specified compressive strength was statistically insignificant. The stress–strain curve of block masonry under uniaxial compression was also obtained. Through nonlinear fitting, the compressive stress–strain relationship of grouted masonry, considering masonry strength parameters, was established, which demonstrated alignment with prior experimental studies. This study not only provides a strength calculation method for grouted masonry structures using high-strength blocks in the code for the design of masonry structures in China but also offers a dedicated stress–strain curve for precise finite element analysis and the design of masonry structures. Full article

Desulfurized gypsum, as a by-product of the wet flue gas desulfurization process in power plants, is one of the main pathways for its resource utilization by preparing new-type desulfurized gypsum hollow block with gypsum core. This paper, based on the research of high-precision desulfurized gypsum materials, conducted axial compressive strength tests on five groups of desulfurized gypsum hollow blocks with concrete core-filling and reinforced masonry. Through regression analysis of the test data, compressive strength and elastic modulus calculation formulas were proposed for such desulfurized gypsum hollow blocks with concrete core-filling and reinforced masonry. The calculated values from the formulas are in good agreement with the experimental values, providing a theoretical basis for the application and research of these masonry structures. Full article

There is an increasing demand to replace traditional construction techniques with more sustainable systems that can reduce environmental impacts. Emissions are typically assessed only in carbon dioxide and embodied energy terms, yet these metrics alone cannot fully capture the overall impact generated. This study provides a comparative Life Cycle Assessment (LCA) of three steel warehouse projects with varying cladding systems: steel walls (SW), steel-clay brick walls (SClaW), and steel-concrete block walls (SConW). Life Cycle Assessment (LCA) methodology was used to assess the environmental impact of materials used during the whole life cycle. The study used the software program SimaPro (System for Integrated Environmental Assessment of Products) version 9.6.0.1, with data extracted from the international Ecoinvent database. ReCiPe Midpoint approach were adopted to assess potential impacts. The results indicate that the SW project under end-of-life Scenario 2—waste recycling—exhibited the lowest impacts across most categories, followed by the SConW and SClaW projects. The findings emphasize the environmental benefits of utilizing steel cladding systems over brick or concrete masonry and considering recycling as the end of life of the materials. Additionally, the study provides insights into the significance of material choices in minimizing environmental impact on human health, resource availability, and ecosystems. Full article

This study evaluates the carbon footprint of three bio-concrete families—wood (WBC), bamboo (BBC), and rice husk (RHBC)—and their application in wall components (as blocks and as boards). A cradle-to-grave, carbon-focused Life Cycle Assessment (LCA) was used to compare these bio-concretes to conventional masonry and industrialized light-framing solutions. Each bio-concrete family incorporated biomass volumetric fractions of 40%, 45%, and 50%, using a ternary cementitious matrix of cement, rice husk ash, and fly ash (0.45:0.25:0.30). Sensitivity analyses examined the impacts of transport distances and the parameters affecting biogenic carbon storage, such as carbon retention periods in the built environment. The carbon footprint results demonstrated a significantly low or negative balance of emissions: WBC ranged from −109 to 31 kgCO₂-eq./m³, BBC from −113 to 28 kgCO₂-eq./m³, and RHBC from 57 to 165 kgCO₂-eq./m³. The findings emphasized the importance of ensuring bio-concrete durability to maximize biogenic carbon storage and highlighted the environmental advantages of bio-concrete wall systems compared to conventional solutions. For instance, BBC boards replacing fiber cement boards in light-framing systems achieved a 62 kgCO₂-eq./m² reduction, primarily due to the production (A1–A3) and replacement (B4) stages. This research outlines the emission profiles of innovative materials with the potential to mitigate global warming through circular construction, offering a sustainable portfolio for designers, builders, and AECO professionals seeking non-conventional solutions aligned with circular economy principles. Full article

This study investigates the mechanical behavior of masonry walls constructed using interlocking compressed earth blocks with dry vertical and horizontal joints. Numerical simulations were conducted to evaluate the performance of this innovative system compared to traditional masonry and to validate experimental findings from previous studies, which identified an orthotropic and non-linear behavior in dry-joint interlocking masonry. The results show that while interlocking masonry exhibits performance comparable to traditional masonry under in-plane loads, it suffers an approximate 20% reduction in resistance under out-of-plane loads, primarily due to the absence of mortar in the horizontal joints. Despite this limitation, the system demonstrates significant economic benefits, achieving cost savings of up to 20% for masonry and 14% for reinforced concrete in conventional construction. These findings highlight the potential of interlocking masonry as a sustainable alternative, although its mechanical behavior under certain load conditions requires further investigation to optimize its structural applications. Full article

In this study, unreinforced masonry (URM) walls constructed from concrete blocks and clay bricks were strengthened using horizontally and vertically oriented glass fiber-reinforced polymer (GFRP) grid strips bonded with sprayed polyurea. The walls were subjected to diagonal compression loading until failure. The results demonstrated a significant improvement in both the shear capacity and pseudo-ductility of the strengthened URM walls compared to their unstrengthened counterparts. The primary conclusions drawn from this research are as follows: (1) the maximum strain in the vertical GFRP strips increased with the higher axial stiffness of the strips; (2) the discrete vertical strips contributed substantially to enhancing the shear capacity and pseudo-ductility of the URM walls; (3) increasing the axial stiffness of the vertical strips can alter the failure mode of the walls, shifting it from joint failure to tension or compression failure of the blocks or bricks; (4) a reduction factor is necessary to account for the potential asymmetrical performance of double-sided strengthening schemes applied to URM walls. The experimental program was reported in a previous publication and additional information is presented in this paper. Full article