Search Results (10)

Reducing thermal losses through building envelopes remains a key strategy in the pursuit of low-carbon, energy-efficient buildings. This study presents an innovative and sustainable retrofitting approach involving thermal insulation plaster modified with finely ground hazelnut shells, an abundant agricultural by-product in Türkiye. The modified plaster is applied symmetrically on both sides of standard masonry briquettes in varying proportions (2%, 4%, and 6%), and its thermal performance is experimentally assessed via the laboratory-scale coheating test method. The results reveal a substantial reduction in U-values compared to the uninsulated briquette (5.5 W/m²K): the 2% shell-modified plaster achieves a U-value of 2.40 W/m²K (56.4% improvement), the 4% variant achieves 2.14 W/m²K (61.1%), and the 6% formulation performs best at 2.04 W/m²K (62.9%). In terms of effective thermal conductivity, the modified plasters exhibit values in the range of 0.0408–0.04856 W/mK. Additionally, the 6% composition exhibits enhanced thermal inertia, delaying internal heat loss and offering extended indoor comfort. All samples demonstrate exceptional measurement repeatability, with day-to-day U-value variation below 2%. These findings surpass thermal performance benchmarks reported in previous studies using bamboo or plaster thickness alterations, and position hazelnut shell-modified plaster as a high-potential solution for sustainable building retrofits. The outcomes offer practical implications for low-cost housing, rural construction, and building refurbishment programmes, while also informing policymakers and material standardisation bodies about scalable bio-based alternatives that align with circular economy and decarbonisation goals. Full article

In 2022, the building sector accounted for 30% of global energy demand and 27% of CO₂ emissions, of which approximately 9% came from building material production. To mitigate this impact, it is critical to develop sustainable alternatives that reduce the environmental footprint of construction materials. This paper presents an original study where the effect of coconut fibre as a reinforcing material in gypsum composites is analysed. These plant-based fibres reduce the composite’s density, improve thermal behaviour, and integrate circular economy criteria in construction. In this way, a physico-mechanical characterisation of these novel gypsum-based composites is addressed, and their potential application for developing prefabricated slabs is innovatively explored. Composites were prepared with coconut fibre incorporation in volume up to 17.5%, and mechanical and thermal properties and their behaviour under water action were evaluated. The results indicate that the fibre addition reduced density by about 10.0%, improved flexural strength by 20.5% and compressive strength by 28.4%, and decreased thermal conductivity by 56.3%, which increased the energy efficiency of the building facade by 7.8%. In addition, hydrophobic properties improved, reducing capillary absorption by 15.9% and open porosity by 3.3%. These findings confirm the technical feasibility of coconut fibre-reinforced plaster for application in prefabricated wall and ceiling elements, promoting the efficient use of natural resources and driving the development of sustainable building materials. Full article

The widespread occurrence of encapsulated phase change materials (PCMs) within a mineral matrix has been demonstrated to improve the thermo-physical properties of final products. The upscaling of such materials has not yet been achieved, as traditional onsite mixing and casting processes could damage the capsule, leading to a leakage of the active content and then a deterioration of the final element. The aim of this paper is to evaluate the influence of selectively depositing a layer of PCM on plaster, through a powder bed 3D printing process, on its density and thermal conductivity. A home-made selective-binding 3D printer has been used to assess samples of composites of calcium sulfate and encapsulated PCM. Thermal conductivity and Scanning Electron Microscope measurements were carried out on pure calcium sulfate as well as on a mix design containing a 5% mass ratio of PCM. The SEM measurements highlight that the PCM shells are undamaged by the selective-binding 3D printing process compared to the traditional mixing and casting process. Also, the 3D-printed composite material demonstrates a thermal conductivity reduction of 39%, which is linked to the 17% decrease in density. This applicative study validates the idea of designing functionally composite construction materials with phase change materials inserted as a thin layer between printed plaster layers and also demonstrates the great potential of this innovative selective-binding 3D printing technique. Full article

Recent seismic events have prompted research into innovative and sustainable materials for strengthening and repairing obsolete and vulnerable buildings. These earthquakes have exposed the high seismic vulnerability of existing reinforced concrete (RC) buildings, particularly in secondary structural elements like infill walls. In addition to structural issues, these buildings often face significant energy deficiencies, such as thermal bridges, due to inadequate insulation. Traditionally, structural and energy improvements for residential buildings are addressed separately with different methods and protocols. This preliminary study is part of a broader research initiative at the University of Reggio Calabria (Italy), aiming to design an innovative fiber-reinforced plaster using natural, sustainable, and locally produced materials to enhance the energy and structural performance of existing wall infills. The study investigates two plaster matrices made of natural hydraulic lime and silica sand, with 15% and 30% cork granules added. Mechanical and thermophysical tests on multiple specimens were conducted to evaluate their suitability for seismic and energy retrofitting of infill walls. Results indicate that adding cork reduces mechanical strength by approximately 42% at a 30% cork content without compromising its use in seismic retrofitting. Thermophysical tests show improved thermal performance with a higher cork content. These findings suggest that the lime–cork mixture at 30% is effective, offering excellent ductility and serving as a promising alternative to traditional cementitious plaster systems. The next experimental phase will test matrices with varying percentages of gorse fiber. Full article

This study reports on the application of an innovative plastering system that reuses organic waste, namely spent coffee grounds (SCG), to improve energy efficiency in historical buildings according to the European Green Deal. The case study was conducted in the village of Polizzi Generosa, selected from 21 small villages located in the extensive UNESCO Geopark of Madonie Park in Sicily. Over time, traditional plasters used in Madonie buildings have shown durability issues due to thermal and hygrometric stresses caused by significant temperature fluctuations in the area. Moreover, much of the considered architectural heritage lacks energy efficiency. Given the global increase in coffee production and the need for more sustainable waste management systems, this investigation proposes an ecological method to reuse SCG in plaster formulation, thereby enhancing the circular economy. To achieve this, many thermoplaster formulations were developed, and the best-performing one, considering both material and aesthetic compatibility with historical buildings, was selected for a real-world application. Additionally, virtual modeling and energy simulations were conducted to test the energy performance of a traditional building in Polizzi Generosa using SCG-based thermoplaster in comparison to traditional lime mortar and commercial alternatives. The real-world application demonstrated the technical feasibility of the process, and the energy simulations showed an improved building masonry energy performance of 0.788 W/m²K and an 11% improvement compared to traditional plaster. Results clearly indicate that SCG can be successfully reused to produce eco-friendly bio composite plasters, providing a more sustainable housing option. This approach offers a durable and cost-effective alternative for housing solutions that meet regulatory requirements for energy efficiency, serving as a smart, highly sustainable, and long-lasting choice for the construction sector. Finally, this result supports the research goal of transforming the 21 municipalities of Madonie into smart and green villages, with the “Smart Coffee-House” exemplifying intelligent rehabilitation processes of existing heritage buildings. Full article

This paper presents a new layered plaster-based material for building purposes. First, a new manufacturing machine was designed to make the elaboration process easier. This manufacturing machine and the way it works are described. In this study, perlite and recycled glass wool (RGW) were added to traditional plaster with the aim of improving the performance of this material. Two series (with and without perlite) and three different layer configurations were developed and assessed. Recycled glass wool layered materials were subjected to both physical and mechanical characterisation to determine their suitability for precast elaboration. The addition of perlite resulted in a significant improvement in flexural strength. Moreover, the addition of RGW also gave rise to extra flexural strength when added. The two-layered samples performed better than the one-layered samples. Mechanical properties increased up to 75% when both the perlite and RGW layers were added. Potential Global Warming Potential (GWP 100) savings were also analysed, reporting up to 49% savings. A complementary cost analysis was performed, aimed at establishing potential savings in production costs; thus, 13–57% potential cost savings were reported. After that, a comparative analysis within the literature was conducted to contextualise the results obtained in this study. Full article

This paper proposes an innovative multi-material approach for introducing auxetic behaviour to syntactic foams (SFs). By carefully designing the size, shape, and orientation of the SFs, auxetic deformation behaviour was induced. Re-entrant hexagon-shaped SF elements were fabricated using expanded perlite (EP) particles and a plaster of Paris slurry first. Then, an auxetic pattern of these SF elements was arranged within a stainless-steel casting box. The empty spaces between the SF elements were filled with molten aluminium alloy (A356) using the counter-gravity infiltration casting technique. The cast auxetic composite had a bulk density of 1.52 g/cm³. The cast composite was then compressed under quasi-static loading to characterise its deformation behaviour and to determine the mechanical properties, especially the Poisson’s ratio. The cast composite deformation was auxetic with a Poisson’s ratio of −1.04. Finite Element (FE) simulations were conducted to understand the deformation mechanism better and provide means for further optimisation of the geometry. Full article

The Fatimid state was established in Egypt in 969 and lasted until the end of the dynasty in 1171. During the Fatimid rule in Egypt, a large set of monuments were erected. A significant portion of these monuments were shrines dedicated to the descendants of the Prophet Muhammed, especially in Aswan. Groundwater rising, at present, has introduced severe deterioration to the ancient earthen mud-brick architecture of the Fatimid tombs in Aswan city (Egypt). However, monitoring the influence of anthropogenic and environmental aspects on the deterioration issues in Fatimid tombs has not yet been considered. To this end, the scope of this pilot study is to investigate the structural stability and weathering vulnerability of the building materials of mud-brick structures in the Fatimid Cemetery before restoration labor. This was achieved using an integration of remote sensing (Landsat 8 and SRTM-DEM) and hydrogeological datasets in the Geographic Information System (GIS), along with a physicochemical and mineralogical analysis of various materials (the bearing soil, wall plasters, and Muqarnas) from the affected cemeteries. The morphological and mineralogical compositions of the collected samples were analytically examined by using X-ray diffraction (XRD) and scanning electron microscopy with energy dispersive X-ray spectroscopy (SEM/EDX) and CT scan. Moreover, geotechnical studies were conducted for the perched soil water and subsoil, including the analysis of the physiochemical composition and heavy metals using Inductively Coupled Plasma Mass Spectrometry (ICP-MS). The results of multitemporal analysis of land use/land cover (LULC) changes displayed the growth and appearance of wetlands near the Fatimid tombs area over the last decades, boosting the geo-environmental risks from soil water rising. Furthermore, the detailed analytical investigations of building materials and soil foundations showed that this unique and substantial ancient Islamic archaeological site of Egypt shows weak geotechnical properties, and it is highly sensitive to natural and anthropogenic stressors. This innovative methodology can produce novel recommendations and results to the Ministry of Antiquities in Egypt and the Heritage Commission in Saudi Arabia for the adequate restoration of monuments. Full article

Natural and bio-based thermal insulation materials play an important role in the lifecycle impact of buildings due to their influence on the amount of energy used in indoor temperature control and the environmental impact of building debris. Among bio-based materials, cork is widespread in the Mediterranean region and is one of the bio-based materials that is most frequently used as thermal insulation for buildings. A particular problem is the protection of the cork-agglomerated panels from external stress and adverse weather conditions; in fact, cork granulates are soft and, consequently, cork panels could be damaged by being hit or by excessive sun radiation. In this study, an innovative external coat for cork-agglomerated panels made of a blending composite of beeswax and rosin (colophony) is proposed. The performance of this composite, using different amounts of elements, was analysed to discover which mix led to the best performance. The mix of 50% beeswax and 50% rosin exhibited the best performance out of all the mixes. This blend demonstrated the best elongation and the lowest fracture density, characteristics that determine the durability of the coating. A performance comparison was carried out between cork panel samples coated with lime render and beeswax–rosin coating. The coating of beeswax and resin highlighted a detachment value about 3.5 times higher than the lime plaster applied on the side of the cork. Full article

An innovative laboratory procedure is described for testing the mechanical adhesion of new dehumidified mortars applied in the restoration works. A specific adherence test was carried out on composite specimens made by stone block and repair mortar. During the laboratory test the acoustic emission (AE) technique was employed, in order to estimate the amount of energy released from fracture propagation in the adherence surface between mortar and stone. A numerical simulation follows the experimental data. The evolution of detachment process of mortar in a coupled stone brick–mortar system was analysed by AE signals, which can improve the numerical model and predict the failure mode in the adhesion surface of repair plaster. Full article