Search Results (105)

Currently, the cement industry stands as one of the sectors with the most significant environmental impact, primarily due to its substantial greenhouse gas emissions and energy consumption. To mitigate this impact, a roadmap has been followed in recent years, outlining a set of objectives aimed at diminishing the environmental footprint of the construction industry. This research focuses on the development of mortars with different water/cement ratios employing an alternative cement, specifically magnesium phosphate cement (MPC) formulated with secondary sources. The goal of this research relays in developing mortars based on MPC by using waste from the metallurgical industry, named tundish deskulling waste (TUN), as an MgO source. The results revealed the optimal water/cement (W/C) ratio for MPC-TUN mortars production through the assessment of various characterization techniques, which was 0.55. This ratio resulted in the highest compressive strength after 28 days of curing and the formation of a stable K-struvite matrix. Furthermore, it demonstrated the effectiveness of aluminum sulphate in preventing efflorescence caused by carbonates. The development of alternative masonry mortars for application in building materials represents a significant stride towards advancing the principles of a circular economy, in alignment with the objectives laid out in the 2030 roadmap. 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

Current construction site conditions and practices often lead to various forms of waste, which in turn decreases productivity and value generation. Lean principles aim to minimize waste while maximizing value. However, optimizing construction flow, especially in masonry construction, remains challenging due to skilled labour shortages and rising material costs. This study developed a framework to identify and mitigate inefficiencies and reduced productivity in current construction practices. Utilizing simulation modelling, various interventions and lean scenarios were evaluated to test their effectiveness. Among the interventions evaluated, the combination of modular construction, interlocking blocks, and robotic technology yielded the most significant improvement. The results validate the potential of integrating lean practices and robotic technology to enhance productivity and efficiency in masonry construction. 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

Concrete is amongst the most wasted materials on earth, mainly due to building demolitions. Currently, after a building’s end of life, concrete is crushed to be used as replacement gravel in new concrete mixes or for backfilling. Aiming to increase the circularity of the construction industry, this article presents design explorations and a design-to-construction process for building single-leaf masonry walls from large flat demolition concrete rubble, thus avoiding the need for further crushing after initial demolition. The proposed process augments the capabilities of conventional construction machinery with new digital control and sensing devices that are widely available on the market and at low cost. The design-to-construction process is implemented through methods of physical prototyping and load testing of a full-scale demonstrator to benchmark the construction precision and the structural, environmental, and productivity performances. The results highlight the viability and scalability of the approach, calling for a more systematic reuse of concrete rubble as it allows for the construction of low-carbon masonry structures while diverging part of concrete waste from downcycling and landfilling. Full article

The contribution of this study is in the novel application of the bin packing algorithm that is used to optimize the robotic bricklaying process with the aim of minimizing the wearing of a robotic saw used for splitting brick blocks so as to minimize brick consumption. To optimize the cutting of masonry blocks with a robotic saw, a new bin packing algorithm has been developed to enhance the design of a digital cutting plan. The algorithm is based on the principle of random search for all combinations of cutting execution with respect to the maximum number of objects (cuts) found in one container (masonry block). The new bin packing algorithm (NBPA) minimizes the number of total masonry blocks (containers) and the number of cuts made with a robotic saw, thus reducing the cutting length. The algorithm can converge to a solution rather quickly and reliably to identify optimal variants of a digital plan designed for a robotic saw to be used in different object assemblies. This article describes the optimization algorithm, including step-by-step calculations, and provides a practical example and a comparison of the results with earlier algorithms. The concept of the robotic saw is also presented in detail, including a description of a prototype. The simulation of the performance on 20 different sets of elements showed that NBPA has a similar use of space compared to the First-Fit Decreasing algorithm (FFD). Multicriteria analysis demonstrated that when the weighting criterion for saw wear was 40% of all the criteria, the use of NBPA was approximately 3.5 times more effective than FFD. The application of the new methodology to a robotic bricklaying process has the potential to reduce the wear of robotic saw, to increase the speed of the construction process and to reduce the generation of construction and demolition waste (CDW). Full article

This study investigated the mechanical properties of a cementitious material used to prepare irregular-shaped brick masonry structures (PG-ISBs) from industrial solid wastes, including phosphogypsum, calcium powder, cementitious agents, and construction brick debris. The hydration products, microstructure, and elemental composition of the system were analyzed using X-ray diffraction (XRD) and scanning electron microscopy (SEM). Based on the experimental stress–strain relationship curves, a constitutive model for the cementitious material was established. The results show that the compressive strength of the PG-ISB cementitious material meets the requirements for filling retaining walls. SEM observations reveal a significant number of micro-pores within the PG-ISB cementitious material, which are important factors affecting its strength. An empirical constitutive model for the uniaxial compression of the specimen was established based on the experimental stress–strain full curves, and the fitting curves showed good agreement with the experimental data. Full article

The development of energy-efficient and sustainable construction materials is essential for reducing environmental impact and enhancing building performance. This study investigates the incorporation of coffee grounds and expanded perlite waste—two underutilized industrial byproducts—into clay-based ceramics to improve thermal insulation while maintaining mechanical integrity. Unlike previous studies that explore these additives separately or in impractically high dosages, this research focuses on their combined effect at low, industrially viable ratios to ensure large-scale feasibility. Four clay mixtures were analyzed: a reference clay (TZ), clay with coffee grounds (TZCF), clay with expanded perlite waste (TZPW), and clay with both additives (TZCFPW). Laboratory testing and computational fluid dynamics (CFD) simulations were employed to assess the physical, mechanical, and thermal properties of these formulations. The results indicated that coffee grounds increased plasticity, while expanded perlite waste reduced it, requiring adjustments in processing parameters. Both additives contributed to lower shrinkage and drying sensitivity, improving dimensional stability during production. Although mechanical strength declined due to increased porosity—most notably in the TZPW mixture—the fired bending strength remained within acceptable limits for masonry applications. The most significant finding was the substantial improvement in thermal performance, with all the modified formulations exhibiting reduced thermal conductivity and enhanced insulation. The best performance was observed in the TZPW mixture, which demonstrated the lowest thermal conductivity, highest thermal resistance, and optimal U-values in masonry wall testing, confirming its potential for energy-efficient construction. CFD simulations further validated these enhancements, providing detailed insights into heat transfer mechanisms. These findings demonstrate the feasibility of repurposing industrial waste materials to create scalable, eco-friendly building products. Future research should refine formulation ratios to optimize the balance between strength and insulation, ensuring widespread adoption in sustainable construction. Full article

This study investigated the use of activated biochar derived from olive stone waste and recycled masonry aggregates in porous mortar mixtures and assessed their behaviour under accelerated carbonation curing conditions. Three mortar mixtures were produced, incorporating 0%, 5%, and 10% activated biochar by volume. The physical, chemical, and mechanical properties of the mortars were analysed, including the compressive strength, flexural strength, water absorption, porosity, and CO₂ capture capacity. Additionally, calorimetry tests were performed on cement pastes with 0%, 0.5%, 1%, 3%, 15%, and 20% activated biochar to evaluate their impact on setting times and ensure compatibility between activated biochar and cement. The results showed that the addition of biochar improved mechanical properties, particularly under accelerated carbonation curing, whereas active biochar (AcB) significantly enhanced the compressive and flexural strengths. Furthermore, biochar incorporation boosted CO₂ capture efficiency, with the 10% biochar mix showing up to 147% higher CO₂ uptake, compared with a control. These findings suggest that activated biochar and recycled masonry aggregates can be effectively utilised to develop sustainable construction materials and thereby contribute to carbon sequestration and the reduction in environmental impacts. This research fills the gaps in the current knowledge on the use of activated biochar from olive stones waste in cement-base materials under accelerated carbonation conditions. Full article

A new type of prefabricated constructional column (PCC) made of recycled lump concrete is proposed and investigated in this study. The methods for the design, fabrication, and construction of this PCC are introduced, and the connection and implementation of the PCC are explained in detail. In order to examine the performance of the PCC, an experimental study on PCC segments was first conducted. Low cyclic load tests of walls restrained by the PCC and cast-in-place constructional column (CCC) were then carried out. The failure of the PCC did not occur at the connection position of the segments, indicating that the connection method was reliable. Compared with the CCC-restrained wall, the failure characteristics of the PCC wall were basically the same; the ultimate bearing capacity was slightly lower, while the displacement ductility and energy dissipation performance were better. Finally, finite element analyses of these two types of masonry walls were implemented under low cyclic loading. The calculated results for cracking, stiffness, ultimate bearing capacity, failure process, hysteretic performance, skeleton curve, energy dissipation, and ductility all had good agreement with the experimental results. The proposed PCC can achieve a prefabrication rate of more than 85%, and the amount of new concrete can be reduced by more than 25% by filling concrete waste lumps, which can greatly improve construction efficiency and reduce the cost, thereby offering significant economic and environmental benefits. Full article

Sustainable development relies on the circularity in the built environment, which, in turn, includes recycling construction and demolition waste and using recycled materials. However, using fine recycled fractions is challenging, especially considering the requirements for new building applications. Yet, producing more widely applied recycled coarse aggregates usually leads to the simultaneous generation of recycled sand fraction, which contains many fines that pose potential problems. This work presents the direct incorporation of concrete and mixed waste-based recycled sand and recycled fines in masonry mortars, on the one hand, as a complete aggregate replacement and, on the other, only replacing the finest aggregate fraction. Such mortars are assessed based on the fresh and hardened mortar properties and are compared to natural aggregate-containing mortars. In the fresh state, the mortars with recycled fines and recycled sand required more mixing water to produce comparable consistency and workability. In a hardened state, mortars with recycled mixed waste sand and fines have demonstrated increased mechanical strength compared to natural aggregate mortars. In contrast, those containing recycled concrete aggregates and fines were inferior in that regard. This indicates the potential of using recycled mixed waste fractions to improve masonry mortar performance, although both types might be important in enhancing the sustainability of masonry construction. Full article

Used tires (UTs) are a global problem, especially in developing countries due to inadequate management systems. During retreading, when the worn tread is replaced, waste is generated in the form of tire fibers (TFs) and particles, which can be reused as raw materials to produce economically and environmentally low-cost prefabricated elements. Using TFs as a lightweight aggregate in nonstructural geopolymer-based elements is a sustainable valorization option. This study aims to valorize used tires by incorporating them as TFs into lightweight geopolymer mixes and analyzing their physico-mechanical, thermal, and thermography properties for building and civil engineering applications. The geopolymer is produced from a precursor (spent catalyst residue from catalytic cracking, FCC) and an alkaline activator composed of rice husk ash (RHA), sodium hydroxide, and water. The control sample’s (mortar with siliceous sand, CTRLSIL) compressive strength came close to 50 MPa, while the TF mixes ranged from 32 to 3 MPa, which meet the masonry standards. The thermal conductivity and thermography analyses showed that increasing the TF content reduced the heat transmission and achieved a similar performance to expanded-clay concrete and better performance than for conventional concrete. Full article

The objective of this research is to analyze the spatial, functional, and constructive aspects of the water resource at the Archaeological Center of Tipon, given the lack of awareness towards the timely preservation of archaeological heritage, the deterioration of the terraces, and the contamination of the rivers adjacent to the archaeological site due to the discharge of waste into the water bodies. The methodology employed consists of a site study analysis, considering data on terrain, environment, climate, and water flow in the spatial, functional, and constructive aspects, supported by digital tools (Google Earth Pro 2024, AutoCAD 2024, SketchUP 2024, Sun Path 3D 2024, Photoshop 2024, and Twinmotion 2024). The results yielded a spatial–functional–constructive hydrological analysis; the water flow, constructed underground through a masonry system with an approximate angle of 60° in stone or pink granite, also maintained a negative slope, generally between 1% and 3%, which facilitated a rapid and direct distribution, presenting a greater flow with a width and depth of 30 cm, in addition to a vertical drop of 240 cm. The efficient use of water in agriculture through interconnected terraces ensured the population’s sustenance by approximately 80%. In conclusion, the analysis not only provides information on the infrastructure and water management but also addresses current issues. Full article

Low water resistance is the main shortcoming of unfired earth materials, requiring chemical stabilisation for some durable applications. Ordinary Portland cement (PC) is an efficient stabiliser, but it goes against the ecological and sustainable nature of earth construction. This study explores the use of low-carbon thermoactivated recycled cement (RC) obtained from old cement waste as a new eco-efficient alternative to PC in the stabilisation of compressed earth blocks (CEBs). The objective is to improve the durability of the CEB masonry even when applied in direct contact with water, without compromising its eco-efficiency. The water resistance of the CEBs with 0% (unstabilised) and 5% and 10% (wt. of earth) stabiliser and partial to total replacement of PC with RC (0, 20, 50, 100% wt.) was evaluated in terms of compressive strength under different moisture contents, immersion and capillary water absorption, low-pressure water absorption, water permeability and water erosion. Low absorption and high resistance to water erosion were achieved in stabilised CEBs, regardless of the type of cement used. The incorporation of RC increased the total porosity and water absorption of the CEBs compared to PC, but significantly improved the water resistance of the unstabilised blocks. The eco-friendlier RC proved to be a promising alternative to PC stabilisation. Full article

This study investigates the feasibility of incorporating shredded polyethylene terephthalate (PET) post-consumer plastic waste as a partial replacement for coarse aggregates in unreinforced concrete such as masonry blocks. Standard concrete blocks were produced with varying PET content (0%, 5%, 25%, 35%, 50%) and tested for workability, air content, density, compressive strength, flexural strength, and thermal conductivity. Results indicated that replacing up to 25% of traditional aggregates with PET maintains adequate compressive strength for non-load-bearing applications and enhances thermal insulation by reducing the thermal conductivity from 0.7 W/m·°K to 0.27 W/m·°K at 25% replacement level, representing a significant improvement of approximately 61%. Higher PET content (35–50%) resulted in reduced structural integrity but improved insulation, suggesting its suitability for non-structural applications. This research highlights the potential of using PET plastic waste in unreinforced concrete, promoting sustainable construction practices by reducing plastic waste and conserving natural resources. Full article