Search Results (79)

Current regulatory principles focus on resistance and durability to ensure long-term robustness while optimizing sections to maximize efficiency and minimize material use, thus enhancing sustainability and reducing environmental impact. Historical ceramic masonry constructions fully adhere to these principles; however, they have been largely supplanted by modern materials. The compressive strength and functional advantages of structures built with ceramic masonry, particularly those featuring extremely thin wall sections, warrant a reassessment of their structural properties. This is exemplified by thin-tile vaults (ranging from 0.015 to 0.020 m in thickness) and hollow brick vaults with a thickness of less than 0.050 m, both of which represent highly efficient solutions. The proposed examples inherently meet these structural system properties due to their low energy dispersion, minimal gravitational weight, superior thermal performance, and monolithic tectonic composition using a single, easily recyclable material. This paper reviews the historical background of these construction systems, emphasizing their relevance in post-war periods when concrete and steel were scarce. It is concluded that these construction systems remain valid and are consistent with the principles of the circular economy, as well as with the structural safety standards of the 21st century. Full article

Building facade insulation technologies have evolved from primitive thermal barriers to high-performance, multifunctional systems that enhance energy efficiency and indoor comfort. Historical insulation methods, such as thick masonry walls and timber-based construction, have gradually been replaced by advanced materials and innovative facade designs. Studies indicate that a significant proportion of a building’s heat loss occurs through its external walls and windows, highlighting the need for effective insulation strategies. The development of double-skin facades (D-SFSs), adaptive facades (AFs), and green facades has enabled substantial reductions in heating and cooling energy demands. Materials such as vacuum insulation panels (VIPs), aerogels, and phase change materials (PCMs) have demonstrated superior thermal resistance, contributing to improved thermal regulation and reduced carbon emissions. Green facades offer additional benefits by lowering surface temperatures and mitigating urban heat island effects, while D-SF configurations can reduce cooling loads by over 20% in warm climates. Despite these advancements, challenges remain regarding the initial investment costs, durability, and material sustainability. The future of facade insulation technologies is expected to focus on bio-based and recyclable insulation materials, enhanced thermal performance, and climate-responsive facade designs. This study provides a comprehensive review of historical and modern facade insulation technologies, examining their impact on energy efficiency, sustainability, and future trends in architectural design. 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 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

The high seismic vulnerability of unreinforced masonry buildings urgently calls for researchers to develop sustainable reinforcing methods and materials. This paper presents an innovative lime-based mortar reinforced with randomly oriented basalt fibers for the reinforcement of masonry heritage. The main aim of this study is to understand the effect of the content and the length of basalt fibers on the mortar’s mechanical behavior. As a cementitious material made mostly out of lime, the mortar is chemically compatible with the historical substrate and therefore suitable in cases of restoration works on architectural heritage. Moreover, the chopped basalt fibers are randomly oriented, and this characteristic makes the overall layer effective in all directions, as the state of stress induced by seismic action is directionally undetermined. The newly proposed reinforcement system is characterized by a twofold aspect related to sustainability: 30% of the aggregates composing the mortar mix design is a recycled result of the ruins of the 2009 L’Aquila earthquake, and the chopped fibers are made out of basalt, widely known for its environmentally supportable peculiarity. The study consists of testing samples characterized by two fiber lengths and six fiber contents, along with one set of plain mortar samples. Specimens measuring 160 mm × 40 mm × 40 mm are first tested in a three-point bending (TPB) configuration, aiming to determine the flexural strength and the post-peak capacity through the calculation of the fracture energy. Then, the two broken pieces resulting from the TPB tests, each measuring 80 mm × 40 mm × 40 mm, are tested in splitting and compression, respectively, aiming to compute the tensile and compressive strengths. Finally, to provide a trend for the mortar’s mechanical properties, a regression analysis is performed by fitting the experimental data with simple linear, polynomial, and exponential regression models. Results show that: (i) both fiber content and fiber length are responsible for a linear increase of the flexural strength and the fracture energy; (ii) for both short- and long-fiber mortar samples, the tensile strength and the compressive strength parabolically increase with the fiber content; (iii) the increase in fiber content and fiber length always generates a reduction in the conglomerate workability. The fiber content (FC) optimization with respect to the mechanical properties leads to a basalt FC equal to 1.2% for long-fiber samples and an FC equal to 1.9% for short-fiber ones. 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

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 research presents an experimental analysis of the mechanical behavior of masonry mortars incorporating disposable face masks (FMs) cut into two different sizes. The objective is to provide experimental data contributing to the consolidation of recycling FMs in mortar mixtures. To achieve this, two types of mixtures were prepared: one with strips of 3 × 3 mm and another with strips of 3 × 10 mm. These FM strips were added in different proportions by the volume of mortar (0%, 0.2%, 0.5%, 0.8%, 1.0%, and 1.5%). In all mortars, the dry bulk density, volume of permeable voids, and water absorption, as well as compressive, flexural, and tensile strengths, were evaluated after a 28-day water immersion curing period. Additionally, two essential properties in masonry mortars were analyzed: air content and shear bond strength. The results indicated that, for both strip sizes, adding FMs up to 0.2% positively affected the flexural and tensile strengths; concerning control mortar, increases of 6% and 1.4%, were recorded, respectively, for the longer strips. At this percentage, the density, air content, and compressive and shear bond strengths are not significantly affected. The results demonstrated that incorporating FMs into mortar mixtures is a promising avenue for sustainable recycling and helps reduce microplastic environmental contamination. Full article

This review presents the scope of current efforts to utilize recycled construction and demolition waste in mortars for masonry. More than 100 articles are divided into groups pertaining to the type of mortar, different binder systems, the type of construction and demolition waste (CDW), and its utilization specifics. Cement-based mortars dominate this research domain, whereas recycled concrete is the main material employed to replace virgin aggregates, followed by recycled masonry and recycled mixed waste aggregates. Such application in cement-based mortars could increase water demand by 20–34% and reduce strength by 11–50%, with recycled concrete aggregates being the most favorable. Natural aggregate substitution is disadvantageous in strong mortars, whereas weaker ones, such as lime-based mortars, could benefit from this incorporation. The extent of this topic also suggests possibilities for different recycled material use cases in mortars for masonry, although the available literature is largely insufficient to infer meaningful trends. Nonetheless, the most relevant knowledge synthesized in this review offers promising and environment-conscious utilization pathways for recycled concrete and other construction and demolition waste, which brings opportunities for further research on their use in mortars for masonry and industrial-scale applications. Full article

In recent times, climate change has become more evident than ever, and measures to slow down its negative effects are imperative for the future of the world. The scientific and economic communities of countries around the world, under the force of international climate agreements, are identifying solutions to reduce greenhouse gas (GHG) emissions by establishing appropriate measures and developing new strategies. In the context of these objectives, the effort to identify eco-sustainable practices for the construction industry is growing significantly. Recently, much research has focused on solutions for producing green building materials, as well as applying circular economy principles to achieve a balance between anthropogenic emissions and absorptions by greenhouse gas absorbers. The relevant indicators of the level of achievement of these major objectives can be identified, already from the construction design phase, with the help of Life Cycle Assessment (LCA) analysis. This paper presents a series of environmental impact analyses for an eco-friendly solution of precast concrete masonry blocks. Ecological concrete is manufactured with aggregates from biological waste resulting from hemp crops. Impact assessments were performed with the SimaPro 9.5 software application. Research has shown that in the production chain, which includes the materials resulting from the recycling and reuse of hemp concrete blocks, the contribution to the effort to achieve neutrality in terms of global warming is significant. The Cradle-to-Cradle scenario revealed that the recycling of hemp concrete masonry blocks at the end of their use, for a functional unit of 0.5 m³, has a GHG emission of 33.5228 [kg CO₂-eq] and CO₂ uptakes can reach the negative value of −53.8397 [kg CO₂-eq]. Thus, the balance of GHG emissions is negative, with values of approximately −20.3169 [kg CO₂-eq]. The LCA analyses also reflect a decreased damage to human health, natural resources, and biodiversity when hemp concrete is used for masonry blocks. Full article

This study evaluates the characteristics of geopolymer masonry mortars (GMMs) made with slag–fly ash binder and up to 100% recycled fine aggregates (RFAs). For each RFA replacement rate, two types of GMMs, namely N and S types based on ASTM C91, were proportioned and tested for mechanical, physical, and durability properties. Results revealed that using geopolymeric binder enhanced the flow, water retention, compressive strength, sorptivity, and abrasion resistance of GMMs compared to cementitious counterparts but reduced the initial setting time by up to 75%. Subsequent RFA additions negatively affected the flow, setting time, density, water absorption, porosity, and bulk resistivity but enhanced the water retention, sorptivity, and abrasion resistance of GMM. It also reduced the compressive, pull-off, and flexural strengths by 36, 44, and 27%, respectively. Furthermore, S-type mortars exhibited improved bulk resistivity, sorptivity, and abrasion resistance compared to N-type counterparts. A multifunctional performance index deduced that the GMM mixes incorporating 100% RFAs were superior to geopolymeric or cementitious masonry mortars made with natural fine aggregates (NFAs). Such findings emphasize the sustainability of GMMs made with RFAs in masonry construction, eliminating the need for water curing while maintaining comparable or even superior properties compared to cement-based mortars made with NFAs. Full article

In the realm of sustainable construction materials, the quest for low-environmental-impact binders has gained momentum. Addressing the global demand for concrete, several alternatives have been proposed to mitigate the carbon footprint associated with traditional Portland cement production. Despite technological advancements, property inconsistencies and cost considerations, the wholesale replacement of Portland cement remains a challenge. This study investigates the feasibility of using alkali-activated slag (AAS)-based binders for two specific applications: structural plaster and pervious concrete. The research aims to develop an M10-grade AAS plaster with a 28-day compressive strength of at least 10 MPa for the retrofitting of masonry buildings. The plaster achieved suitable levels of workability and applicability by trowel as well as a 28-day compressive strength of 10.8 MPa, and the level shrinkage was reduced by up to 45% through the inclusion of shrinkage-reducing admixtures. Additionally, this study explores the use of tunnel muck as a recycled aggregate in AAS pervious concrete, achieving a compressive strength up to 20 MPa and a permeability rate from 500 to 3000 mm/min. The relationship between aggregate size and the physical and mechanical properties of no-fines concretes usually used for cement-based pervious concrete was also confirmed. Furthermore, the environmental impacts of these materials, including their global warming potential (GWP) and gross energy requirement (GER), are compared to those of conventional mortars and concretes. The findings highlight that AAS materials reduce the GWP from 50 to 75% and the GER by about 10–30% compared to their traditional counterparts. Full article

The construction sector generates a strong environmental impact every year as a result of the high consumption of raw materials and the large waste volumes associated with this productive activity. In this sense, the search for alternative and sustainable solutions that allow progress towards responsible economic growth has become a priority activity. This work presents an exhaustive characterisation of masonry mortars made with four different types of aggregates: standard sand, natural sand, concrete waste recycled sand and ceramic components recovered sand. Differently from other studies, this research addresses the previous characterisation of the aggregates as raw material for the manufacture of masonry mortars, and, afterwards, a study of the most relevant properties for these cement composites in the fresh and hardened state is carried out. The most relevant properties of the mortars made with these raw materials are presented, and the repercussion of aggregate washing on their physical-mechanical characteristics is analysed. The results show how mortars made with 100% recycled aggregate can be competitive in the industry, presenting excellent properties in the fresh state and achieving an optimal mechanical strength. In addition, it has been observed that the introduction of a previous washing step of the aggregates improves their physical-mechanical properties and results in a higher quality of the cement mortars finally produced. In this way, the most representative properties of this type of materials have been collected in a well-structured and complete way, thus showing their possibilities of application in the construction industry. Full article

The European Green Deal establishes the efficient management of construction resources as one of its main lines of action. In this sense, the recovery of construction and demolition waste for its reincorporation into the manufacturing process of new sustainable materials has become necessary for the industry. This work deals with the physical and mechanical characterization of cement mortars made with recycled concrete aggregates and reinforced with natural fibers. The reinforcement fibers used (abaca, coconut, and toquilla) are more environmentally friendly compared to traditional synthetic reinforcements. The aim of this research is to analyze the main physico-mechanical properties of these sustainable cement mortars. The results show that mortars made with recycled sand have a lower density and better thermal performance than traditional mortars. In addition, with the incorporation of these natural fibers, the flexural strength of the mortars with recycled aggregate increased by up to 37.6%. Another advantage obtained from the incorporation of these natural fibers is the reduction in shrinkage in the masonry mortars during the drying process, giving them greater dimensional stability and making their behavior similar to that of traditional mortars. Thus, this work shows the potential application of masonry mortars produced under circular economy criteria and their application in the building sector. Full article