Composite Building Research Articles

Study on preparation and property of coir fiber reinforced epoxy resin composite geogrid

Based on the development and application of green composite building materials, this study prepared a coir fiber reinforced epoxy resin composite grid using coir fiber as the reinforcement material. Through tensile tests of a multi rib grid, the effects of coir fiber content, length, and rib spacing on the composite grid were studied. The results showed that with increase in the coir fiber content, the tensile yield force first increased and then decreased, reaching the maximum value at coir fiber content of 1%. When the coir fiber content exceeded 1%, the tensile properties of the composite grid were lower than that of pure epoxy resin. With the increase in the coir fiber length, the tensile yield force of composite grid also first increased and then decreased. At a fiber length of 1 cm, the maximum tensile yield force was obtained, which was 34.33% higher than that of pure epoxy resin grid. Compared with the influence of fiber length and content on the composite grid, the influence of rib spacing on the composite grid was more obvious. At a rib spacing of 1 cm, the tensile yield force reached its maximum.

Seismic evaluation of existing reinforced cement concrete building and steel–concrete composite building

Seismic evaluation of existing reinforced cement concrete building and steel–concrete composite building

Interzeolite Transformation from FAU-to-EDI Type of Zeolite.

This study reports for the first time the transformation of the pre-made FAU type of zeolite to the EDI type of zeolite. The concentration of the KOH solution controls this interzeolite transformation, which unusually occurs at both room temperature and under hydrothermal conditions. The transformation involves the amorphization and partial dissolution of the parent FAU phase, followed by the crystallization of EDI zeolite. At room temperature, the transformation (11-35 days) provides access to well-shaped nano-sized crystals and hollow hierarchical particles while the hydrothermal synthesis results in faster crystallization (6-27 h). These findings reveal an example of an interzeolite transformation to a potassium zeolite that lacks common composite building units with the parent zeolite phase. Finally, this work also demonstrates the first room-temperature synthesis of EDI zeolite from a gel precursor.

Magnesium Oxychloride Cement: Development, Opportunities and Challenges

Magnesium oxychloride cement (MOC), an alternative to ordinary Portland cement (OPC), has attracted increasing research interest for its excellent mechanical properties and its green and sustainable attributes. The poor water resistance of MOC limited its usage mainly to indoor applications; nevertheless, recent advances in water-resistant MOC have expanded the material’s potential applications from indoor to outdoor. This review aims to showcase recent advances in MOC, including water-resistant MOC and ductile fiber-reinforced MOC (FRMOC), exploring their potential applications including in sustainable construction for future generations. The mechanism under different curing procedures such as normal and CO2 curing and the effect of different inorganic and organic additives on the water resistance of MOC composites are discussed. In particular, the review highlights the recent developments in achieving over 100% strength retention under water at 28 days as well as advancements in FRMOC, where tensile strength has surpassed 10 MPa with a remarkable strain capacity ranging from 4–8%. This paper also sheds light on the potential applications of MOC as a fire-resistant coating material, green-wood-MOC composite building material, and in reducing solid waste industrial byproduct accumulations. Finally, this study suggests future research directions to enhance the practical application of MOC.

Experimental Analysis on Partial Replacement of Cement by Glass Powder and Using of Steel Fiber

Abstract: Concrete consists of fine aggregate, coarse aggregate, water, and optional admixtures, such as Portland cement or another hydraulic cement. Because of its massive resource consumption, the concrete industry poses a serious danger to the sector's long-term viability. The concrete industry is struggling in part because of concerns about the environment and the economy. Many studies are currently being conducted on the utilisation of waste materials like Pulverised Fly Ash (PFA) and Ground Granulated Blast Furnace Slag (GGBS) as supplemental cementitious materials. Similar to PFA and GGBS, waste glass powder can be used to partially substitute cement during the hydration reaction. To some extent, waste glass can substitute cement in concrete and contribute to strength development if it is ground to a very fine powder and demonstrates pozzolanic properties due to its high SiO2 content. This research examined the Compressive, Tensile, and Flexural strengths of concrete that had been aged for up to 60 days with concrete that had been partially replaced with Glass Powder at percentages ranging from 0% to 40%. The aggregate test findings suggest that Waste Glass Powder could be used as a suitable cement replacement in construction projects. Fibre reinforced concrete (FRC) is a composite building material made from small, discontinuous fibres that are randomly distributed throughout the concrete part. Steel, glass, and polymer fibres, as well as fibres originating from natural sources, are the most common types of fibre used in cement-based composites. The tendency of fibres to be more closely spaced than traditional reinforcing steel bars makes them more effective at preventing cracking. It's important to note that fibre is not a suitable replacement for steel bars when reinforcing concrete.

POLYMER COMPOSITES FOR EXTERNAL REINFORCEMENT OF BUILDING STRUCTURES

Key aspects of developing effective systems for the external reinforcement of building structures, made of composite polymer materials containing carbon fibers and no-bake polymer binders, ensuring shape formation in the temperature range of 15 - 40 °С no more than 24 hours, characterized by operability in the temperature range from minus 45 ° C to plus 60 ° C.. PCM-based SVA has a number of advantages compared to clips and metal profiles traditionally used for repairing building structures: the load-bearing capacity of the rods increases, the cost of the strengthening of load-bearing structures is reduced, and the seismic resistance of engineering structures is increased. In relation to composite SVA building structures, the following types of construction chemicals are used: primer, putty, adhesive, protective coating. The production of unidirectional tapes was carried out on a Dornier double rapier loom, modernized for processing carbon fibers. The results of experimental studies of the developed polymer binders and carbon reinforcing fillers are presented. It is shown that the developed materials can be successfully used to strengthen and repair engineering structures. The technological features of strengthening and repairing building structures with composite external reinforcement systems using the contact molding method and ready-made lamellas are described. Installation of composite clamps on vertical surfaces is carried out by fixing the canvas in the extreme position, followed by laying, smoothing and rolling along its length. Rolling is done from the middle to the edges. Before gluing the blanks, the lamellas are laid out on a work table (workbench) and thoroughly wiped with a rag moistened with acetone. Results of the large-scale implementation of these new materials and technologies in the construction industry are presented.

Resin acid derivatives: fungicidal properties and prediction of the spectrum of biological activity

Biologically active substances that confer antiviral, anti-tumour and antimicrobial effects, which are found among the components of plant raw materials, as well as the products of their chemical modification, are the subject of considerable research interest. These objects include tricyclic diterpenoids – extractives of wood of abietic and pimaric types (resin acids). The presence of two reaction centres (double bonds and a carboxyl group) in the structure of resin acids opens up a wide range of possibilities for synthesising useful compounds on their basis. One of the most promising areas for the study of resin acids and their derivatives consists assessing their fungicidal properties to inform their introduction into compositions as additives, as well as in the application of protective films to increase the resistance of composite building materials against the aggressive effects of microorganisms. In the present work, the fungicidal activity of the N-phenylimide of maleopimaric acid and its polyfluoroalkyl ethers synthesised by us was evaluated on the cells of the filamentous fungi Aspergillus niger, Alternaria alternata and Penicillium sp. by the rate of colony formation and growth. A comparative analysis of the biological activity of resin acids and their in silico derivatives was performed. According to the AntiBag Pred forecast, the test compounds having the maximum values of the probabilities of the presence and absence of each type of activity are characterised by the manifestation of antibacterial activity in relation to strains of gram-positive bacteria. The results of the predictive model are consistent with previous experimental data. However, AntiFun Pred data related to the calculation of fungicidal activity were not confirmed in vitro.

Investigation of the interface of fungal mycelium composite building materials by means of low-vacuum scanning electron microscopy.

Low-vacuum scanning electron microscopy (low-vacuum SEM) is widely used for different applications, such as the investigation of noncoated specimen or the observation of biological materials, which are not stable to high vacuum. In this study, the combination of mineral building materials (concrete or clay plaster) with a biological composite (fungal mycelium composite) by using low-vacuum SEM was investigated. Fungal biotechnology is increasingly gaining prominence in addressing the challenges of sustainability transformation. The construction industry is one of the biggest contributors to the climate crises and, therefore, can highly profit from applications based on regenerative fungal materials. In this work, a fungal mycelium composite is used as alternative to conventional insulating materials like Styrofoam. However, to adapt bio-based products to the construction industry, investigations, optimisations and adaptations to existing solutions are needed. This paper examines the compatibility between fungal mycelium materials with mineral-based materials to demonstrate basic feasibility. For this purpose, fresh and hardened concrete specimens as well as clay plaster samples are combined with growing mycelium from the tinder fungus Fomes fomentarius. The contact zone between the mycelium composite and the mineral building materials is examined by scanning electron microscopy (SEM). The combination of these materials proves to be feasible in general. The use of hardened concrete or clay with living mycelium composite appears to be the favoured variant, as the hyphae can grow into the surface of the building material and thus a layered structure with a stable connection is formed. In order to work with the combination of low-density organic materials and higher-density inorganic materials simultaneously, low-vacuum SEM offers a suitable method to deliver results with reduced effort in preparation while maintaining high capture and magnification quality. Not only are image recordings possible with SE and BSE, but EDX measurements can also be carried out quickly without the influence of a coating. Depending on the signal used, as well as the magnification, image-recording strategies must be adapted. Especially when using SE, an image-integration method was used to reduce the build-up of point charges from the electron beam, which damages the mycelial hyphae. Additionally using different signals during image capture is recommended to confirm acquired information, avoiding misinterpretations.

Thermal properties of a raw earth-flax fibers building material

The aim of this paper is to investigate the thermal behavior of composite building materials comprised of silt and flax fibers, considering various initial conditions. The experiments were conducted on flax fibers alone, examining factors such as moisture content variation, fibers arrangement, and density. Subsequently, the thermal properties of the earth-flax fiber composite were studied, taking into account the influence of water content and fibers mass content. The thermal properties of both flax fibers and raw earth-flax fibers composite specimens were determined using the experimental unsteady-state method. The results indicate that the thermal conductivity and heat capacity of flax fibers increase with density, temperature, and moisture content. Regardless of fibers density and arrangement of fibers, linear relationships have been established for both thermal conductivity and heat capacity as functions of temperature. Additionally, it was demonstrated that the heat capacity and the thermal conductivity increase with water content, regardless of the percentage of added fibers. Moreover, mixing randomly flax fibers with compacted raw earth material has improved the thermal properties of the composite. This improvement pertains to its insulating capacity, ability to store heat, and, subsequently, its contribution to the thermal comfort provided by such earth composite material when used as a building material.

Spent ion-exchange resin as a new aggregate to enhance specific heat capacity of composite building materials: A case study on gypsum plaster

Spent ion exchange resin (SIER) is a by-product derived from drinking water treatment plants, possessing intriguing physicochemical properties that render it a promising ingredient for composite building materials. Surprisingly, there has been a luck of research investigating its impact on the performance of such materials. This study addresses this gap by characterizing unfired and fired gypsum-based composites with varying SIER weight ratios (10–50 wt%) and firing temperatures (300, 600, and 900°C). X-ray diffraction, scanning electron microscopy, and the hot disk method were employed to explore the effects of SIER on the composites’ thermal-mechanical features. The results revealed the significance of SIER as a promising waste-based aggregate to enhance the specific heat capacity (cp) of gypsum-based composites. With increasing SIER content and firing temperature, the composites demonstrate improved cp, reduced thermal conductivity, and decreased compressive strength. Both unfired and fired composites exhibited an increase in cp, up to 74.4% and 331.8%, respectively. The composite material achieved a noteworthy reduction in thermal conductivity, reaching 0.132 W/m.K, and a specific heat capacity increase to 4491.35 J/kg.K, which surpasses that of the control sample by more than four times (1040 J/kg.K). These newly developed composites hold significant promise as thermal energy storage materials for low-temperature building applications.

Green building adaptation in hot-humid climates: assessment of coconut and corn husk fiber composite bricks as energy-efficient building envelopes

PurposeThis study has assessed the thermal performance of locally fabricated bio-based building envelopes made of coconut and corn husk composite bricks to reduce building wall heat transmission load and energy consumption towards green building adaptation.Design/methodology/approachSamples of coconut fiber (coir) and corn husk fiber bricks were fabricated and tested for their thermophysical properties using the Transient Plane Source (TPS) 2500s instrument. A simulation was conducted using Dynamic Energy Response of Building - Lunds Tekniska Hogskola (DEROB-LTH) to determine indoor temperature variation over 24 h. The time lag and decrement factor, two important parameters in evaluating building envelopes, were also determined.FindingsThe time lag of the bio-based composite building envelope was found to be in the range of 4.2–4.6 h for 100 mm thickness block and 10.64–11.5 h for 200 mm thickness block. The decrement factor was also determined to be in the range of 0.87–0.88. The bio-based composite building envelopes were able to maintain the indoor temperature of the model from 25.4 to 27.4 °C, providing a closely stable indoor thermal comfort despite varying outdoor temperatures. The temperature variation in 24 h, was very stable for about 8 h before a degree increment, providing a comfortable indoor temperature for occupants and the need not to rely on air conditions and other mechanical forms of cooling. Potential energy savings also peaked at 529.14 kWh per year.Practical implicationsThe findings of this study present opportunities to building developers and engineers in terms of selecting vernacular materials for building envelopes towards green building adaptation, energy savings, reduced construction costs and job creation.Originality/valueThis study presents for the first time, time lag and decrement factor for bio-based composite building envelopes for green building adaptation in hot climates, as found in Ghana.

Tensile Load-Bearing Behaviour of Concrete Components Reinforced with Flax Fibre Textiles.

In recent years, the use of natural flax fibres as a reinforcement in composite building structures has witnessed a growing interest amongst research communities due to their green, economical, and capable mechanical properties. Most of the previous investigations on the load-bearing behaviour of concrete components reinforced with natural flax fibres include inorganic impregnations (or even no impregnation) and exclude the use of textile fabrics. Also, the mechanical behaviour of textiles made of natural flax fibres produced as leno fabrics remains to be investigated. In this paper, the results of tensile tests on concrete components reinforced with bio-based impregnated leno fabrics are presented. For comparison, multilayer non-impregnated and impregnated textiles were considered. The results demonstrated that reinforced textiles yielded an increase in the failure loads compared to the concrete cross-sections without reinforcement. The stress-strain diagrams showed that the curves can be divided into three sections, which are typical for reinforced tensile test specimens. For the impregnated textiles, a narrowly distributed crack pattern was observed. The results showed that impregnated textiles tend to support higher failure stresses with less strains than non-impregnated textiles. Moreover, an increase in the reinforcement ratio alongside larger opening widths of the warp yarns enables higher failure loads.

A comparative analysis of RCC and composite buildings using the new plastic deformation (PD) method

Low computational efficiency and non-linearity behaviour make the simulation of the overall building structure problematic to attain with a single dynamic or static method. Thus, this paper uses a plastic deformation (PD) method based on concrete plasticity theory (CPT) for comparative analysis of multi-storey reinforcement cement concrete (RCC) and composite buildings under common and rare earthquake loads. For this purpose, a 15-storey tall building was selected for analysis using ABAQUS software. At first, a possible building model was created and then plastic deformation analysis was performed using the new PD method under both common and rare earthquakes. After that, a nonlinear time history analysis was conducted, and the results of plastic strain distribution, lateral displacement, peak acceleration, storey stiffness, shear force, storey drift, normalised shear, and top deflection of the RCC and composite buildings were studied deeply. The fundamental time period of the RCC model was found to be 5.2 s while the fundamental time period of the composite model was 6 s. Under common and rare earthquake leads, the peak acceleration of the RCC building was 19% and 22% higher than composite buildings, respectively. Under common and rare seismic loads, the top deflections of the composite building were 33% and 36% higher than those of RCC buildings, respectively. In the case of the RCC building, it was found in this study that higher peak acceleration (PA) of the ground motion led to higher storey top displacement, storey drift, shear force and top deflection under both ground motions. Numerical results suggested that the use of composite structure is more durable than RCC structure. It was also concluded that the PD method could also be effectively used for the analysis of RCC and composite buildings under dynamic loads.

Research on Microclimate Performance Simulation Application and Scheme Optimization in Traditional Neighborhood Renewal—A Case Study of Donghuali District, Foshan City

With global warming and rapid urbanization, the microclimate in the Lingnan region is prone to health problems, such as pyrexia and infectious diseases, and the average annual number of heatwave-related deaths is rising rapidly. The large-scale regeneration of traditional neighborhoods in Lingnan under high-quality development is underway, which has implications for the thermal comfort of microclimatic environments. This study focused on the impact of different building unit types and spatial patterns on thermal comfort in the Donghuali traditional neighborhood of Foshan City as an example. We extracted eight basic morphological units and designed a prototype block of 400 m × 400 m. In the Rhinoceros & Grasshopper parametric software 6.7, a variety of plug-ins were integrated to establish a platform with parametric modeling, microclimate simulation and evaluation, and optimal design for thermal comfort. Through experiments, the effects of new single-type and new composite building units on thermal comfort were investigated, and the correlation equations between spatial morphology and microclimate comfort in Lingnan traditional neighborhoods were established. Finally, the multi-objective genetic optimization of thermal comfort was carried out as an example of real block renewal, which provides a practical reference for the planning and design of traditional blocks.

Experimental Study of Novel Demountable Shear Connectors for Steel-concrete Composite Buildings

Sustainable composite structures in building construction are assembled using demountable structural elements that can be reused in the circular economy. The current research and development project, in cooperation with Budapest University of Technology and Economics and KÉSZ Group, bim.GROUP Ltd., Hungary, aims to design a novel demountable steel-concrete composite slab and frame system for buildings. The key component of this construction is the demountable shear connector. In the current research, novel bolted shear connectors with embedded bolts and threaded rods are developed and studied that can fit the applied technology of the industrial partner. One of the leading aspects of this connection is the consideration of bolt hole clearance, since it occurs initial slip and stiffness reduction of the composite beam. In the first phase of the research program, demountable and economical structural details were developed, which can reduce the stiffness reduction with the proper resistance and ductility features. To study the behavior of these shear connections, a push-out experimental program was designed and completed in March and April 2023. It is observed that novel shear connectors have a proper behavior with sufficient resistance and ductility, which is applicable according to the Eurocode 4 standard and fits the objectives of the research and development project. In the paper, the developed structural details and the push-out experimental program are presented with general results and statements besides a detailed evaluation of a specified specimen type.

Fire protection costs in composite buildings for cost-benefit analysis of fire designs

As performance-based design approaches are increasingly emerging as alternatives to prescriptive designs for buildings under extreme hazards, the economic impact of adopting the former over the latter needs to be assessed. Here, we describe a method for quantifying the costs of fire protection in composite steel frame structures under different fire designs. A cost database is constructed for 130 prototypes of steel framed composite buildings with different occupancies, dimensions, and fire ratings using a commercial cost estimator. The cost of passive fire protection on steelwork is found to range from 0 to 1.20% of the total construction cost for composite buildings with sprayed fire resistive material in the United States. A generalized method is then developed to evaluate fire protection costs in composite buildings, including the effect of different structural fire designs such as the optimized allocation of fire protection through performance-based fire design. The method is applied to a case study of a 15-story office building to compare the costs associated with fire protection for three designs. The method can be incorporated into a cost-benefit analysis to evaluate the lifetime economic impact of various structural fire designs.

Study on the optimization of wave absorption of glass substrate indium tin oxide film composite building materials

Study on the optimization of wave absorption of glass substrate indium tin oxide film composite building materials

Comparative Study of R.C.C. and Composite Structures Under Different Soil Conditions

Abstract: The need for multi-storey buildings arises from a fact that it offers vertical expansion, making them an ideal choice for maximizing available urban space without influencing valuable land resources. A thorough literature review has conducted for comparative study of RCC and Composite buildings and its various advancements conducted before. This paper is based on regular and irregular plan area under different soil conditions. Total 18 cases have taken for consideration (6- square shape, 6 – L shape and 6 – T shape plan) with 3 cases each of RCC and 3 cases for Composite building and method selected - Response Spectrum Method. Results for Square shape plan shows that SCPH case i.e. Square plan with Composite structure over hard soil performs well in most of the output parameters. Results for L shape plan shows that LCPH case i.e. L shape plan with Composite structure over hard soil performs well in most of the output parameters while in case of story displacement and drift LRCCH i.e. L shape plan with RCC structure over hard soil performs better but the values of LCPH are also within the limits of IS codes. Results for T shape plan shows that in case of story displacement and drift TRCCH i.e. T shape plan with RCC structure over hard soil performs better because of the higher stiffness of RCC structure while in all other output parameters TCPH i.e. T shape plan with composite structure over hard soil performs well. Concluding the research work, use of composite structure performs well and can be used with building stability techniques so that the displacement factors can be minimized for composite structures.

Ultralight, strong, and self-reprogrammable mechanical metamaterials.

Versatile programmable materials have long been envisioned that can reconfigure themselves to adapt to changing use cases in adaptive infrastructure, space exploration, disaster response, and more. We introduce a robotic structural system as an implementation of programmable matter, with mechanical performance and scale on par with conventional high-performance materials and truss systems. Fiber-reinforced composite truss-like building blocks form strong, stiff, and lightweight lattice structures as mechanical metamaterials. Two types of mobile robots operate over the exterior surface and through the interior of the system, performing transport, placement, and reversible fastening using the intrinsic lattice periodicity for indexing and metrology. Leveraging programmable matter algorithms to achieve scalability in size and complexity, this system design enables robust collective automated assembly and reconfiguration of large structures with simple robots. We describe the system design and experimental results from a 256-unit cell assembly demonstration and lattice mechanical testing, as well as a demonstration of disassembly and reconfiguration. The assembled structural lattice material exhibits ultralight mass density (0.0103 grams per cubic centimeter) with high strength and stiffness for its weight ( 11.38 kilopascals and 1.1129 megapascals, respectively), a material performance realm appropriate for applications like space structures. With simple robots and structure, high mass-specific structural performance, and competitive throughput, this system demonstrates the potential for self-reconfiguring autonomous metamaterials for diverse applications.

Fabrication and characterization of lignocellulosic coconut and energy reed straw-reinforced methylene diphenyl diisocyanate-bonded sustainable insulation panels

The use of renewable environmental resources and plastics that can be returned to the biological cycle shows a new direction in the application of composite building materials. This study investigated the potential and strengthening effects of developing composite panels from coconut materials (CM) and reed straw (RS) particles in the presence of methylene diphenyl diisocyanate (MDI). Five composite panels with 100:0, 60:40, 50:50, 40:60, and 0:100% proportions were produced. The nominal density was 600 kg/m3 and the dimensions were 400 × 400 × 8 mm3. The panels were produced by hot-pressing for a total of 10 min at a maximum pressure of 7.2 MPa and at 135 degrees, and then slowly cooled at room temperature. The following experiments were performed: mechanical, physical and morphological properties, thermal conductivity, FTIR (Fourier transform infrared spectroscopy), and EDX (Energy disruptive X-ray). The study gave the following results: the thermal conductivity of the coir and reed panels is competitive with the thermal insulation capacity of similar natural-based insulation materials, and is close to the values of other mineral and plastic-based insulation materials. The values of thermal conductivity coefficient ranged from 0.08 to 0.10 W/(mK). Only reeds (MDI_1) boards have better results than coconut materials. Among the mechanical properties, flexural strength and internal bonding strength increased proportionally with the increase in the amount of coconut. The Young's modulus reached its maximum in the case of a 50–50% coir-reed mixture. The best values of the panels are: 6.33 MPa for flexural strength, 1.83 GPa for Young's modulus and 0.36 MPa for internal bonding strength. The morphological recordings confirmed the proper mixing and binding of the lignocellulosic materials in the composite. FTIR tests proved the successful chemical interactions. The findings support the possibility of creating a promising, environmentally friendly building material.