Construction Of Composite Materials Research Articles

Enhanced Thermal and Flexural Properties of Alkalized Date Palm/Kenaf Fiber-Reinforced Epoxy Hybrid Composites: A Comparative Study of Untreated and Treated Fibers

ABSTRACT This study evaluates the thermal and mechanical behavior of hybrid composites made from date palm (DP) and kenaf fibers (KF) in an epoxy thermoset matrix. Both DP and KF fibers are abundant and renewable, reducing environmental impact. KF offers high tensile strength and stiffness, improving composite strength and rigidity, while DP fibers offer toughness and impact resistance, enhancing durability. The composites were developed in 30%, 50%, and 70% DP-KF compositions using layup and hot-pressing methods. Fiber treatment through alkalization was analyzed for its impact on mechanical and thermal properties to find the optimal fiber ratio. The hybrid composites were subjected to DMA, TGA, and flexural tests. The treated composites exhibited fewer impurities and increased cellulose content, resulting in enhanced flexural performance. This improvement was evident through higher storage modulus, lower loss modulus, and reduced tan δ when exposed to thermal stress. The 30% DP and 70% KF composites exhibited best performance. The treated 30DP-70KF exhibited improvement in the flexural strength and modulus by 13.8% and 2.7%, respectively. TGA demonstrated that treated 30DP-70KF composites had a higher glass transition temperature (Tg) and better thermal degradation resistance. These findings highlight the potential of natural fiber hybrids in creating sustainable, high-performance composite materials for construction and industrial applications.

Advancing bamboo fiber reinforcement: A novel approach using eco-friendly plant ash alkali treatment.

This study aimed to enhance the engineering performance of bamboo fibers for use in composite materials by employing a sustainable plant ash alkali treatment. The primary objective was to improve the tensile strength, crystallinity, and thermal stability of bamboo fibers, which are known for their high specific strength, low density, and biodegradability but suffer from poor compatibility with hydrophobic matrices. The study involved treating bamboo fibers with varying concentrations of plant ash solutions (5 %, 10 %, 20 %, and 30 % by mass fraction) and comparing the results with those from conventional NaOH treatment. The results showed that plant ash treatment at a 20 % concentration significantly improved tensile strength by 14.16 % compared to untreated fibers, increased the crystallinity index to 75.57 %, and enhanced thermal stability, retaining more residual mass at high temperatures than NaOH-treated fibers. These improvements are attributed to the reduction in fiber polarity and better preservation of fiber structure. The findings suggest that plant ash, as a cost-effective and eco-friendly alternative to NaOH, can significantly enhance the mechanical and thermal properties of bamboo fibers, making them suitable for use in environmentally sustainable composite materials in construction, and other industries.

Optimizing sustainability and resilience of composite construction materials using life cycle assessment and advanced artificial intelligence techniques

Optimizing sustainability and resilience of composite construction materials using life cycle assessment and advanced artificial intelligence techniques

Integrated Technologies for Anti-Deicing Functions and Structures of Aircraft: Current Status and Development Trends

With the increasing adoption of composite materials in aircraft construction, traditional anti-icing technologies face significant challenges due to the low thermal conductivity and heat resistance of composite resins. These limitations have spurred the development of lightweight, efficient, durable, and cost-effective integrated anti-icing technologies as a critical area of research. This paper begins with an overview of advancements in electrothermal anti-icing and de-icing technologies for aircraft. It then explores the configurations and applications of functional-structural integration technology for anti-icing and de-icing, emphasizing pivotal technologies and current challenges in this field. Finally, the study forecasts the development trends in the multifunctional integration of thermal conductivity/insulation, anti-icing, and electromagnetic wave transparency/wave-absorbing properties. These advancements are driven by the evolution of composite materialization in aircraft and the progression of multi-electrical/all-electrical technologies. The objective is to provide a comprehensive guide for technological development in anti-icing, aiding researchers and relevant departments to further enhance the application of anti-icing technology in composite material aircraft.

Исследование технологических характеристик элемента трубошпунтовой завесы и самозабуриваемых анкеров из полимерных композиционных материалов

The use of high-tech polymer composite materials in construction makes it possible to carry out work under the constraints of transport infrastructure, limited space at a construction site, or in difficult operating conditions. The paper presents the results of studies of the technological characteristics of a pipe-and-pile curtain element made of carbon fiber and fiberglass, a self-drilling anchor made of fiberglass and steel used in modern construction

A Brief Analysis of The Production of Building Materials Utilizing Waste-Based Reinforcements and Recycled Textiles

The utilization of composite materials in construction has recently exerted a significant impact on society, particularly concerning ecological responsibility and environmental considerations. On a daily basis, proposals advocating the use of emerging materials crafted from discarded or repurposed items are put forth to transcend the limitations posed by conventional resources. One notable aspect of this movement revolves around textile components, encompassing fibres such as wool, cotton, cannabis, and flax. Over the past decade, there has been a heightened focus on worn clothing, as it represents an unprocessed product that holds both commercial viability and ecological benefits. Approximately 1.5 percent of the global waste generated daily comprises textile scraps, with blue jeans, crafted from cotton, standing out as the most prevalent type of apparel worldwide. Textile scraps find new life through recycling, serving various purposes such as the creation of electrical wires, the production of pulverized substances for temperature and acoustic insulation materials, and the incorporation as filler or reinforcement in concrete construction. This paper delves into multiple themes, covering (i) the adverse environmental impacts stemming from the extensive use of clothing; (ii) the recycling and reclamation of textile waste; and (iii) the utilization of waste and reclaimed materials from textiles as building components.

Low binder content bricks: a regolith-based solution for sustainable surface construction on the Moon

This work proposes a composite construction material made by a blend of lunar regolith and thermoplastic binders in dry powder form. This solution offers advantages over regolith sintering or melting by requiring lower power consumption and simplifying the manufacturing process. However, its sustainability depends on minimizing the content of the binder material. Drawing from validated concepts used on Earth, such as polymeric concrete and compressed Earth bricks, this paper suggests that binder optimization can be achieved by simplifying and streamlining the manufacturing process, targeting parts with predefined shapes. Standardized elements like bricks or tiles ease production and assembly automation, especially when incorporating interlocking features, simplifying the payload concept transition. After drafting the process with a minimum number of basic steps, this work studies the effects of some process parameters to minimize the weight percentage of the matrix while maintaining reasonable mechanical properties. The compressive and the flexural strength are the targets of an orthogonal array Design of Experiment. Through comparison with reference values for civil engineering, the process demonstrates promising results within an organic phase as low as 10 wt%.

Development of an effective technology for producing composite wood-plastic board materials for construction and furniture purposes

This article presents the results of research in the development of an effective technology for obtaining composite wood-plastic board materials for construction and furniture purposes based on fillers from cotton stalks, which are agricultural waste, and polymer binders based on modified urea-formaldehyde and gossypol resins, epichlorohydrin, benzyl chloride, and polyvinyl chloride. The study revealed a correlation between the ultimate bending strength, tensile strength and water absorption with the parameters of pressing polymer-fillers of the mass. At the same time, to obtain composite wood-plastic board materials, it is recommended to use a urea-formaldehyde resin modified with reactive structuring additives as a binder. It has been established that the optimal technological mode for pressing the mass of polymer fillers and cotton stalks is: specific pressure 35 kg/m², pressing temperature 168-170°C, heating duration 7-10 minutes. Key words: technology, composition, modified urea-formaldehyde resin, cotton stem filler, wood-plastic board, specific pressure, pressing temperature, heating duration, water absorption, tensile strength.

PROPERTIES INVESTIGATION OF POLYESTER RESIN COMPOSITE MATERIALS AND PRODUCTS

The use of composite materials in construction is a promising direction due to their potential to reduce costs and improve the operational characteristics of building structures. The results of this study will allow to determine the optimal formulations and manufacturing technologies of polymer composite materials for use in construction. In this paper, a detailed analysis of the composite material based on polyester resin (polymer sand concrete) used for the manufacture of hatch covers for manholes in water supply and sewage systems is carried out. The main components of the considered composition are quartz sand, unsaturated polyester resin, hardening accelerator - cobalt naphthenate solution and hardener - benzoyl peroxide. As part of the study, the improvement of the composite material’s properties is also considered by adjusting the technological modes of formation. Special attention was paid to the analysis of the hardness of the samples after the research, since this parameter determines the resistance of the material to wear. The effect of different ratios of these components on the physical and mechanical properties of the final material was studied. It was experimentally determined how the consumption of polyester and hardener affects the compressive strength, bending strength, impact toughness and hardness of the composite material. To obtain optimal characteristics, the STATISTICA 12 software package was used to specify the values of the factors that lead to maximum compressive and bending strength. The results of the research are presented in the conclusions in the form of quantitative indicators that indicate the optimal composition to achieve high physical and mechanical characteristics. The response surfaces of the variation factors’ influence on the properties of interest are shown. Keywords: composite material, polymer sand concrete, quartz sand, polyester resin, hardening accelerator - cobalt naphthenate solution and hardener - benzoyl peroxide

Bibliometric Analysis of Bio- and Earth-Based Building Materials: Current and Future Trends

The energy and environmental transition in the building sector requires the development and use of low-impact materials. Despite the growing interest in bio-based and earth-based building materials, their widespread adoption is still limited due to a lack of hindsight, as their study is relatively recent. This study aims to contribute to the development of these materials by providing an extensive overview of key contributors (authors, countries, journals) in these fields. Then, the keywords of the corresponding publications were analyzed to reveal the main topics covered to date. First, a broad scale is presented, followed by a focus on sub-categories, specifically raw materials for bio-based building materials and implementation techniques for earth-based ones. Finally, a comparative analysis, with the themes covered by composite construction materials as a whole, completes the study. Using statistical analysis coupled with bibliometric network visualization software, this study provides clear, quantifiable, and objective insights into current trends. Furthermore, it facilitates the identification of new, promising research perspectives and highlights the importance of interdisciplinary collaboration. Physics, modeling, durability and microstructure studies emerge as relevant levers for advancing the future development of these eco-friendly building materials.

Studying the Efficiency of Composite Longitudinal and Transverse Reinforcement for Increasing the Strength and Rigidity of Flexible Eccentrically Compressed Reinforced Concrete Poles

Introduction. In recent years, the use of composite materials for improving the operational properties of the building constructions within the restoration process is gradually replacing the methods, developed for this purpose in the middle of the XXth century and implying the use of reinforced concrete and metal. However, the regulatory framework stipulating the process of strengthening the loadbearing structures of buildings and structures was developed based on the insufficient amount of experimental data. Due to this fact, the large number of structures, exceeding the normative limits, cannot be strengthened with the composite materials, or such strengthening incurs significant economic costs. Thus, nowadays, the experimental studies on strengthening the reinforced concrete structures with composite materials are considered to be forward-looking and relevant. The aim of this study is to analyse the results of a number of experiments conducted to investigate the use and efficiency of composite materials in construction. Materials and Methods. To determine the level of stress in composite carbon materials of the external reinforcement of the eccentrically compressed reinforced concrete poles, the tests were carried out with four specimens. All specimens were strengthened using different reinforcement schemes. The strain gauges with 2cm active measuring grid length were installed in the zones of the most evident work of the composite materials to measure the changes of relative deformation at each load level during testing of the specimens. From 10 to 16 strain gauges were installed at each structure, depending on the importance of the zones for determining the deformations.Results. The work presents the results of the study on determining the efficiency of composite longitudinal and transverse reinforcement for increasing the rigidity and strength of flexible eccentrically compressed reinforced concrete poles. The experimental data on the composite materials’ strength, deflections and relative deformations, obtained during testing of four reinforced concrete poles, is presented. The efficiency of composite reinforcement at ultimate strength and ultimate deflections is assessed. The relative deformations in composite materials are determined and the inclusion of the reinforcement system in the work of the strengthened reinforced concrete specimens is assessed.Discussion and Conclusion. Based on the obtained results, the analysis of the composite reinforcement efficiency has been carried out, and proposals have been developed on designing the reinforcement systems of the flexible eccentrically compressed reinforced concrete poles working with the large eccentricities of the load application.

Editorial for the Special Issue on Sustainable Composite Construction Materials

Sustainable composite construction materials play a crucial role in creating more environmental friendly and energy-efficient buildings [...]

Free‐form reinforced concrete, prestressed concrete, and composite components: Calculation of cross‐section values

AbstractA resource‐efficient use of concrete as a construction material can be achieved by adapting the individual shape of a component under consideration to the stresses that occur and by arranging composite construction materials (e.g., reinforcing steel, prestressing steel, or structural steel) in suitable areas of the component. Due to the advancing digitalization in the construction industry, for example in the context of Building Information Modeling, computer‐aided 3D modeling methods are increasingly being used in the planning of structures. These allow engineers to design components in free form. In reinforced concrete, prestressed concrete, and composite construction, the design of such components is currently still associated with great effort. In the context of the development of a practical method for the calculation of free‐form concrete components, this paper presents a CAD‐integrated method for the calculation of cross‐section values. Cross‐section values are required as an essential calculation basis when real, three‐dimensional structural components are treated using simplified calculation theories, such as the beam theory. In this paper, the mathematical and numerical fundamentals of a method for the calculation of cross‐section values of free‐form concrete, reinforced concrete, prestressed concrete, and compound components are presented. The calculation method is based on flat geometric regions described by Non‐uniform Rational B‐Spline tensor product surfaces, which can be extracted from solid models, for example.

Experimental Research on Anti-freezing and Thawing Performance of Basalt Fiber Reinforced Fly Ash Concrete in the Corrosive Conditions

Basalt fiber reinforced fly ash concrete (BFRFAC) is a new inorganic nonmetal composite construction material with excellent mechanical properties that could be widely used for bridge floors, pavements, and other construction engineering projects. The anti-freezing and thawing performance of BFRFAC in the corrosion circumstances was studied in detail with a comparison to normal concrete (NC) by using quick freezing method in this work. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the control group, the mass loss rate (MLR) and relative dynamic modulus of elasticity (RDME) on BFRFAC were determined in non-corrosion environment. In the experimental group, the RDME on BFRFAC were determined in chloride corrosion, sulfate corrosion, the complex combined corrosion of chloride and sulfate solution. Further, a scanning electron microscope (SEM) was employed to scan the meso-structure of the rupture cross-section in t-he composite material at magnifications of 500, 1000, and 1500. The gripping effect between basalt fibers and su-bstrate was quantitatively analyzed in the case of pull-out failure and fracture failure, which convincingly reveal-ed the crack resistance, reinforcement, and toughening mechanisms of basalt fibers on concrete substrate. We found that RDME decreased and its descent rate slows down when BFRFAC was exposed to freeze-thaw cycles in above-mentioned four situations. The number of freeze-thaw cycles of BFRFAC was greater than 400 in the complex case of solution corrosion. The BFRFAC cyclic lifespan could be effectively extended in contrast to NC. Moreover, make full use of volcanic ash and micro-aggregate effect of fly ash can improves the gripping effect between basalt fibers and concrete substrate. As a result, it has the potential to significantly improve anti-freezing and thawing damage capacity of BFRFAC.

STUDY OF REGULARITY OF CHANGES IN VOLUMETRIC MASS OF FOAMED GEOPOLYMER MATERIALS ON BASIS OF LIMESTONE WAST

The creation of composite construction materials, which have a less harmful impact on the environment both at the stage of their production and in the process of their use, is of great interest in the global construction industry. Recent innovations have led to the creation of foamed geopolymer concrete or geopolymer foam, which includes the operational advantages of thermal and acoustic insulation materials, saves energy by reducing heat loss, and contributes to the reduction of CO2 emissions into the environment. For a better understanding of the properties and benefits related to the use of foamed geopolymer materials, this paper presents studies of the volumetric mass of these materials obtained from limestone waste and silicate activator. Samples with a ratio of components (limestone waste: activator) of 70:30, 75:25, and 80:20 were obtained. Studies of the volumetric mass depending on changes in the concentration of alkali in the solution of the gas generation activator showed that the minimum values of the volumetric mass are achieved at 1 mol/L concentration of alkali. In addition, it was found that the best foaming geopolymer material is achieved at a ratio of components of 80:20 and at a content of the gas generation activator solution in the mixture of 18% mass. Keywords: foamed geopolymer, volumetric mass, porosity, thermal insulation material.

STUDY OF REGULARITY OF CHANGES IN VOLUMETRIC MASS OF FOAMED GEOPOLYMER MATERIALS ON BASIS OF LIMESTONE WASTE

The creation of composite construction materials, which have a less harmful impact on the environment both at the stage of their production and in the process of their use, is of great interest in the global construction industry. Recent innovations have led to the creation of foamed geopolymer concrete or geopolymer foam, which includes the operational advantages of thermal and acoustic insulation materials, saves energy by reducing heat loss, and contributes to the reduction of CO2 emissions into the environment. For a better understanding of the properties and benefits related to the use of foamed geopolymer materials, this paper presents studies of the volumetric mass of these materials obtained from limestone waste and silicate activator. Samples with a ratio of components (limestone waste: activator) of 70:30, 75:25, and 80:20 were obtained. Studies of the volumetric mass depending on changes in the concentration of alkali in the solution of the gas generation activator showed that the minimum values of the volumetric mass are achieved at 1 mol/L concentration of alkali. In addition, it was found that the best foaming geopolymer material is achieved at a ratio of components of 80:20 and at a content of the gas generation activator solution in the mixture of 18% mass. Keywords: foamed geopolymer, volumetric mass, porosity, thermal insulation material.

Changing the approach to sustainable constructions: An adaptive mix-design calibration process for earth composite materials

One major drawback of excavation earth-based composite construction materials is the variability in excavation earth characteristics from site to site. This variability can affect certain physical properties, and, in turn, the design models used to create a structure. To solve this problem, a methodology has been developed to predict the physical properties of earth-based composites for any mix-design variation, which enables a robust structural design process.This new methodology has been tested for Shot-earth, a new class of earth-based composite material made using high rates of excavation earth, aggregates, and a low rate of stabilization if needed. Shot-earth is placed using a high-speed dry-mix process.The methodology was tested by preparing small, inexpensive specimens through a process that simulates the dry-process used to fabricate Shot-earth in the field. An adaptive technique, used in conjunction with the experimental methodology, allows for the identification of the variant of possible Shot-earth mix-designs that provides optimal physical properties for a specific project. This technique is potentially applicable to any type of earth-based composite. The proposed methodology's reliability enables a fast and cost-effective detailing of Shot-earth constructions.

Neural Network Aided Homogenization Approach for Predicting Effective Thermal Conductivity of Composite Construction Materials.

Thermal conductivity is a fundamental material parameter involved in various infrastructure design guides around the world. This paper developed an innovative neural network (NN) aided homogenization approach for predicting the effective thermal conductivity of various composite construction materials. The 2-D meso-structures of dense graded asphalt mixture, porous asphalt mixture, and cement concrete were generated and divided into 2n × 2n square elements with specific thermal conductivity values. A two-layer feed-forward neural network with sigmoid hidden neurons and linear output neurons was built to predict the effective thermal conductivity of the 2 × 2 block. The Levenberg-Marquardt backpropagation algorithm was used to train the network. By repeatedly using the neural network, the effective thermal conductivities of 2-D meso-structures were calculated. The accuracy of the above NN aided homogenization approach was validated with experiment, and various factors affecting the effective thermal conductivity were analyzed. The analysis results show that the accuracy of the NN aided approach is acceptable with relative errors of 1.92~4.34% for the dense graded asphalt mixture, 1.10~6.85% for the porous asphalt mixture, and 1.13~3.14% for the cement concrete. The relative errors for all the materials are lower than 5% when the heterogeneous structures are divided into 512 × 512 elements. Ignoring the actual material meso-structures may lead to significant errors (134.01%) in predicting the effective thermal conductivity of materials with high heterogeneity such as porous asphalt mixture. While proper simplification is acceptable for dense construction composite materials. The effective thermal conductivity of composite cement-asphalt mixtures increases with higher saturation of grouted material. However, the improvement effect of the high-conductive cement paste on the composite cement-asphalt mixtures could be significantly reduced when the cement paste concentrates at the bottom of the mixture. Cracked aggregates and segregation of material components tend to decrease the effective thermal conductivity of construction materials. The NN aided homogenization approach presented in this paper is useful for selecting the effective thermal conductivity of construction materials.

Nanocomposites as Substituent of Cement: Structure and Mechanical Properties

To date, the scientific research in the field of recycling of construction and demolition wastes was focused on the production of concrete, cements, and bricks. The attainment of these products was limited to the addition of suitable binder contents, such as lime or cement, compaction, and possibly heat treatment, without a concrete recycling method. In this paper, new cement materials consisting of 2.5 weight% composite and originating from construction and demolition waste powder, were prepared and investigated in view of applications in the construction industry as a substituent of cement. The materials with recycled powder from construction and demolition wastes were characterized by X-ray diffraction (XRD), infrared (IR) and nuclear magnetic resonance (NMR) spectroscopy. The XRD data indicate vitroceramic structures with varied crystalline phases. The NMR relaxometry data show four reservoirs of water associated with bounded water and with three types of pores in the composite construction material. The micro-Vickers hardness was measured to reflect the influence of composite nature in the local mechanical properties of the composite-cement for the mixture with Portland cement and (EC) expired cement.

Study on reinforced concrete elements of buildings and structures with cracks, reinforced with composite polymer materials

With the rapid development of modern construction practice around the world, serious problems arise in the application and subsequent operation of reinforced concrete structures. Today, the problem of reconstruction and restoration of buildings and structures requires an urgent solution. The deterioration of the environmental situation threatens the reliability of buildings and structures, a sharp deterioration in their condition is observed in almost all countries and climatic zones. In our case, the trend towards wear is developing due to the imperfection of regulatory documents and the need for proper maintenance of objects. The development of the construction industry and the use of innovative composite polymer materials in construction and the strengthening of existing buildings and structures with modern methods are relevant. Often very rare, expensive, historically significant structures require reliable operation, and their dismantling or replacement is more expensive than repair, or even impossible. Reinforcement of building structures using composite polymer materials (CPM) is by far the most “cautious” measure for their restoration and improvement of performance. In our research, the main attention is paid to the technology of external reinforcement of reinforced concrete beams using CFRP to increase their load-bearing capacity at shear. To reduce material consumption when strengthening the structure, it is more efficient to use CFRP in the form of strips, however, this practice has not been practically studied. Previous researchers have concentrated their attention mainly on external reinforcement, generally ignoring the effect of internal reinforcement. However, it is known that internal and external reinforcement complement each other and the destruction during shearing of reinforced concrete elements is mainly influenced by such factors as steel clamps, longitudinal reinforcement and the ratio of the shear span to the working height of the section. Therefore, in our studies, special attention was paid to considering the influence of these factors on the overall bearing capacity of beams. In addition, the work studied the ability to transfer shear stresses through cracks in reinforced concrete beams reinforced with external reinforcement from CFRP compared to the same unreinforced ones.