Traditional Building Materials Research Articles

Hygro-thermal coupling in earth building materials

Raw earth is emerging as a viable building material with lower carbon emissions than conventional concrete and fired bricks. Raw earth is as an excellent passive hygro-thermal regulator, which improves occupants’ comfort while reducing the need for active heating/cooling installations. The coupled hygro-thermal response of earth materials is investigated by exploiting the principles of the thermodynamics of porous media and unsaturated soil mechanics. The degree of coupling between temperature and relative humidity (or water content) depends on the adopted simplifying assumptions. Some of these assumptions are valid for traditional building materials but may not be applicable to raw earth characterised by relatively high levels of liquid/gas permeability. The validity of current approaches is here assessed with reference to earth building via a simple one-dimensional transfer model, which simulates the behaviour of an unbounded earth wall subjected to time-dependent boundary conditions on the two faces. For typical values of water and vapour permeability, the complexity of the governing equations can be greatly reduced by neglecting variations of vapour mass and the dependency of suction on temperature without significantly reducing accuracy. Results are also strongly influenced by both initial state and water retention properties of the earth material.

Sustainable Infrastructure Solutions: Advancing Geopolymer Bricks via Eco-Polymerization of Plastic Waste

This article investigates the possible synergy between geopolymers and plastics as a method for sustainable composite materials, addressing the growing worldwide need for environmentally responsible solutions. Geopolymers, which provide low-carbon alternatives to traditional building materials, are being studied alongside plastics, which are recognised for their flexibility and lightweight properties. The research emphasises the ability of this composite to attain increased mechanical, thermal, and chemical qualities by investigating molecular-level interaction processes, enhanced material properties, and applications in diverse sectors. Furthermore, the research assesses environmental consequences, such as decreased carbon emissions and energy usage, while also analysing manufacturing and scaling problems. This work lays the way for a unique route in material science, poised to greatly contribute to a more sustainable and resilient built environment, by giving insights into both present accomplishments and future research possibilities.

Bio-based lightweight building blocks: A review

This paper explores the development and utilization of bio-based lightweight building blocks as a sustainable solution in the construction industry. With increasing concerns about the environmental impact of traditional building materials, there is a growing need for eco-friendly alternatives. This study investigates the potential of natural and renewable materials, such as agricultural waste fibers, bamboo, or hemp, in combination with binders to create lightweight building blocks that offer both structural integrity and environmental sustainability. The research focuses on the formulation of these blocks, considering the optimal combination of bio-based materials and binders to achieve the desired properties. The performance characteristics of the bio-based lightweight building blocks, including structural strength, thermal insulation, fire resistance, and durability, are evaluated. The study also highlights the contribution of these blocks to sustainable construction practices, such as reducing carbon footprints and promoting resource efficiency. By providing an overview of the existing research in this field, the paper discusses the benefits and challenges associated with bio-based lightweight building blocks exploring economic feasibility, availability of materials, and compatibility with existing construction practices. Furthermore, the paper suggests avenues for future research, emphasizing the need for standardized testing protocols, certification systems, and a wider implementation of bio-based lightweight building blocks in the construction industry. This study sheds light on the potential of bio-based lightweight building blocks to mitigate environmental impact, improve sustainability, and drive innovation in construction practices.

Analysis of Concrete with Chaff

Can the reintroduction of a traditional building material lessen the emission of greenhouse gas emissions of the construction industry? The study below will present the search for the answer to this question. Given that the used hemp shives, compared to cement, have low mechanical strength but act as a great thermal insulator, I tried four recipes to find the best ratio among the elements after determining the bending, compressive and tensile strengths. The study also analyzes the price of hempcrete, comparing it to the price of hollow bricks, to examine the material’s viability from a financial perspective. Additionally, it compares the carbon dioxide emissions of hempcrete and bricks.

Development of reduced thermal conductivity ductile cement-based composite material by using silica aerogel and silane

Multi-function cement-based materials will show stronger competitive than traditional single-function building materials. Aerogels have attracted widespread attention in cement-based insulation materials because of their extremely low thermal conductivities. However, neither the compatibility between aerogels and matrix matrices nor the strength degradation of cement-based materials with aerogels has been effectively resolved. Therefore, this work aimed to improve aerogels' application prospects in cement-based materials and realize the functional diversity of cement-based composite materials. In this study, high-ductility cement-based composite materials served as the matrix while using aerogel as a lightweight aggregate to replace an equal portion of sand from the original cement. A reduced thermal conductivity ductile cement-based composite (RTCDCC) material was prepared by directly mixing silane into the cement-based material. The effects of the aerogel and silane on the fluidity, strength development, bending performance, thermal conductivity, and density of the slurry under the combined action of the aerogel and silane were systematically studied. In addition, the specimens were tested by nitrogen adsorption, X-ray diffraction, and scanning electron microscopy to investigate the pore characteristics, chemical compositions, and microstructures of the hydration products. The results demonstrated that direct mixing of silane into cement-based materials could improve the degree of bonding between the aerogels and cement-based materials, reducing the adverse effects of mixing these materials and optimizing the pore structure. In addition, when the aerogel content reached 20% with a silane content of 0.8%, the specimen exhibited favorable mechanical properties and ductility with a significantly decreased thermal conductivity.

Preparation of high toughness materials by recycling industrial waste: Performance evolution study and sustainability evaluation

Energy shortage and environmental pollution have become two global problems to be solved urgently. The establishment of the two goals of “carbon peaking” and “carbon neutrality” further makes it clear that the urgent task at present is to coordinate the relationship between development and environment. The main purpose of this study is to develop a green building material with high ductility and environmental friendliness by using solid waste. Eight kinds of fiber-reinforced alkali-activated composites (FRAC) were designed and prepared with blast furnace slag (BFS) and waste photovoltaic glass powder as cementitious materials, and the solution composed of water, sodium hydroxide and water glass as activator. The effects of fiber type, sand-to-binder ratio (s/b) and water-to-binder ratio (w/b) were considered. The fluidity, flexural strength, compressive strength, uniaxial tensile properties, drying shrinkage rate, mass loss rate and microstructure of FRAC were tested. The cost and environmental benefits of FRAC were evaluated using a simplified method and compared with traditional building materials. Finally, TOPSIS (Technique for Order Preference by Similarity to an Ideal Solution) was used to comprehensively evaluate the eight FARCs developed. The results showed that FRAC has excellent properties, and the uniaxial tensile strain was up to 5.68% at 7 d. Compared with traditional building materials, FRAC showed significant environmental friendliness. TOPSIS results showed that the polyethylene (PE) fiber-based FRAC performs better overall than the polyvinyl alcohol (PVA) fiber -based FRAC.

Vascular bundle characteristics and mechanical properties of Dendrocalamus sinicus

Understanding the structure and mechanical properties of the material is a prerequisite for exploiting its potential. Here, this study aims to investigate the basic information and distribution characteristics of the vascular bundles and mechanical properties of Dendrocalamus sinicus to provide theoretical and technical guidance for its exploitation. Nanoindentation, macro-mechanical tests and a recognition model based on the YOLO algorithm developed by the group were used to reveal its structure, micro-mechanics and macro-mechanics. The results revealed that the length, width, length-to-width ratio (The ratio of the length to the width of a single vascular bundle) and area of individual vascular bundles were distributed with a quadratic function along the radial direction, and the mean values of both fiber volume fraction and area of fiber sheath were high, reaching 34.11 % and 0.3301 mm2, respectively. The nanoindentation measurement showed Dendrocalamus sinicus had excellent mechanical properties with an indentation modulus of elasticity of 24.10 GPa and a hardness of vascular bundles of 626.03 MPa. Dendrocalamus sinicus consisting of a large proportion of high-strength fiber sheaths made it highly significant to exhibit excellent macro-mechanical performances, suggesting that Dendrocalamus sinicus has a huge potential for exploitation and can be used as materials for furniture, construction and other fields. It has the potential to replace traditional building materials such as steel and concrete in the future.

Recycling sorghum husk and palm kernel shell wastes for pervious concrete production

Agro-industrial by-products are being used as an alternative to traditional building materials because the construction of buildings and roads emits greenhouse gases and consumes energy. This study explores pervious concrete (PC) that includes sorghum husk ash (SHA) and palm kernel shell (PKS) as alternatives to cement and natural aggregate (NA) to obtain a robust, sustainable and cost efficient pavement structure. Mixtures of PC were produced with 5–25% SHA at a level of 5% by weight as substitution for cement and 20–100% PKS at a level of 20% by weight as substitution for NA. The performance of SHA-PKS based PC was evaluated using density, compressive strength, porosity and permeability. Sustainability of combining SHA and PKS on PC was also examined by measuring embodied carbon and energy as well as cost efficacy. Thereafter, Artificial Neural Network (ANN) models to optimize the prediction of porosity and permeability were developed for the PC. Utilizing the coefficient of determination (R2), mean square error (MSE), and root mean square error (RMSE), the suitability of the ANN models was assessed. Results showed that as SHA and PKS amounts increased, PC densities declined. Except at 5%, when they were higher than the control, compressive strength decreased as SHA increased. On the other hand, the addition of PKS increased PC porosity and permeability while lowering density and compressive strength. Mixture of SHA-blended PKS based PC with 40% PKS and 20% SHA attained the compressive strength, porosity and permeability values specified for PC which is adequate for sidewalks and cycle ways. This mixture lowers the embodied carbon, embodied energy and cost by 23%, 20% and 24% respectively. The adopted ANN models adequately predicted the porosity and permeability of PC (R2: 0.99; MSE: 0.88–1.76; RMSE: 0.94–1.32). The findings of this work offer a sustainable path to recycle SHA and PKS for constructions.

Incentive Regulation of Construction Waste Resource Recycling: Subsidy and Tax Incentive

Construction waste destroys the sustainability of environment and economy. In the study of game theory at present, the construction waste resource-based products supply chain only considers that there is only one type of enterprise producing renewable building materials or new building materials in the market, but in the construction market, there is no single type of enterprise. It isvery important for government to protect the environment and promote the resource utilization and development of construction waste. Therefore, this study establishes a game theory model between traditional building materials enterprise and construction waste recycling enterprise, which considers the decision-making behavior of enterprise under no regulation, subsidy incentive regulation, or tax incentive regulation. The findings are listed as follows: (1) both subsidies and tax incentives can effectively improve the economic benefits and production initiative of construction waste recycling enterprise. (2) The impact coefficient of unit new building materials on the environment and the tax rate of unit new building materials are the key factors that affect government decision-making. (3) Resource utilization cost coefficient and builder’s preference for renewable building materials have a great impact on the profits of construction waste recycling enterprise. These results will provide reference for the government to formulate incentive regulations and promote the development of construction waste resources.

Fabrication of Sound Absorption Gypsum/Hempcrete Composite with Robust Antistatic Electricity by Taguchi Optimization Method

ABSTRACT Hempcrete is a sustainable bio-composite consisting of the woody component of hemp stalk, and lime blended with water. Hempcrete has been considered as an eco-friendly alternative to traditional construction building materials. This study has fabricated hempcrete composite consists of gypsum and hemp shives for sound absorption, and graphite was incorporated to improve the antistatic electricity. Three controlled factors: the length of hemp, the content of hemp, and graphite with four levels for each factor were chosen. Taguchi method based on orthogonal array L16 was employed to conduct the experiments. According to the results of Taguchi’s orthogonal array L16, analysis of variance (ANOVA) was used to evaluate the effects of various factors. The determination of optimal production parameters of gypsum/hempcrete composite was also investigated. According to the analysis, it has indicated that hemp content and graphite were the two most effective parameters on sound absorption, where hemp content exhibited a significant effect at 99% confidence level, and the confidence level of graphite is 95%. The antistatic electricity of gypsum/hempcrete composite is highly related to the incorporation of graphite with 99% confidence level.

Assessment of X-Salt characterization: a salt-based construction material using natural adhesives for additive manufacturing

PurposeDespite the dramatic increase in construction toward additive manufacturing, several challenges are faced using natural materials such as Earth and salt compared to the most market-useable materials in 3D printing as concrete which consumes high carbon emission.Design/methodology/approachCharacterization and mechanical tests were conducted on 19 samples for three natural binders in dry and wet tests to mimic the additive manufacturing process in order to reach an efficient extrudable and printable mixture that fits the 3D printer.FindingsUpon testing compressive strength against grain size, compaction, cohesion, shape, heat and water content, X-Salt was shown to record high compressive strength of 9.5 MPa. This is equivalent to old Karshif and fire bricks and surpasses both rammed Earth and new Karshif. Material flow analysis for X-Salt assessing energy usage showed that only 10% recycled waste was produced by the end of the life cycle compared to salt.Research limitations/implicationsFindings are expected to upscale the use of 3D salt printing in on-site and off-site architectural applications.Practical implicationsFindings contribute to attempts to resolve challenges related to vernacular architecture using 3D salt printing with sufficient stability.Social implicationsBenefits include recyclability and minimum environmental impact. Social aspects related to technology integration remain however for further research.Originality/valueThis paper expands the use of Karshif, a salt-based traditional building material in Egypt's desert by using X-Salt, a salt-base and natural adhesive, and investigating its printability by testing its mechanical properties to reach a cleaner and low-cost sustainable 3D printed mixture.

Novel biodesign enhancements to at-risk traditional building materials

Extreme weather conditions increase the frequency of regular maintenance on heritage buildings and cause erosion of traditional materials. Developments in bio-enhanced self-repair materials provide an opportunity to improve building performance and reduce the frequency of costly maintenance schedules. The microbial sequestration of carbon by bacteria, encapsulated and layered into several limewash coats, facilitates capturing atmospheric carbon and reduces carbon-generating maintenance regimes. The use of hydrogels, alginates and biofilm derived biopolymers as novel bacterial encapsulation and nutrient delivery vehicles is discussed and the opportunity to develop self-healing sacrificial limewash as a future research project. Microbial enhanced carbon-fixing limewash may also offer a broader application to improve the performance of sustainable materials such as hemp-lime bio-composites as a fast-forward projection of problems and solutions with these materials in the future.

Manufacturing of Brick from Medical Waste (MW)

The environmental concern of Medical Waste (MW) generation has escalated to an alarming level due to the versatility and high demand in various applications due to COVID 19. Reusing MW to make construction material looks to be an environmentally acceptable solution to finding an effective way to use them. This is also because traditional building materials take a lot of energy to manufacture, which has numerous negative environmental consequences. This paper summarises prior investigations on repurposing various MW as a construction raw material and aggregate, as well as their quality, with a focus on bricks and paving blocks. This research begins by demonstrating the characteristics of plastics and the environmental effects of MW. After that, there will be a talk of MW reuse and how it influences total construction material quality. According to this study, only a few investigations on the use of MW in the production of paving blocks have been conducted. Furthermore, the majority of studies used compressive strength and water absorption as the principal criteria for evaluating brick and paving block quality. The compressive strength is found to be 12-13 N/mm2 and water absorption is found to be less than 1% for the prepared sample.

USAGE OF RED MUD IN GEOPOLYMER MORTAR MIXTURES

Popular techniques of waste treatment are often very expensive and often difficult to access.Nowadays, billions of tons of valuable waste material are deposited in landfills without using potential. The factthat five to ten percent of the total carbon dioxide emissions coming from civil engineering, actually from theproduction of cement, means that it is necessary to find some alternative materials. Alkali-activated materials -geopolymers are created in order to prevent carbon dioxide emission and to use waste materials. Geopolymersare the result of a chemical process called geopolymerization. They were developed in order to promote fireprotection, but their numerous benefits were observed during the laboratory tests. Materials such as industrialby-products might be used as a binder material because their chemical structure is rich in aluminosilicatecompounds. As in well-known building materials, as it is here, the application of different binder materialsmakes a difference in the material structure. During the process of geopolymer mixtures production, binders andalkali activators required more steps than traditional building materials: like blending the binder materials,dissolving the liquid phase, etc., but in the end, the carbon emission is a few times lower when compared toothers mixtures. It is clear that the greatest benefit of geopolymer is their ecological aspects.The paper presents the results of testing the physical, mechanical, and durability characteristics of geopolymermixtures. Fly ash was used as the primary material, while its partial replacement was made with the addition ofred mud. All geopolymer mortar mixes meet the basic requirements in terms of compressive and flexuralstrengths.The testing was continued on frost and thaw up to twenty-five cycles. It can be concluded that the coefficient ofresistance, in terms of flexural strength is greater than seventy-five percent only in the mixtures made withfifteen percent red mud and on the etalon sample. By calculating the compressive strength resistance parameter,it was concluded that all samples of geopolymer mortar that are made of fly ash and with the addition of redmud are freezing and thawing resistant up to twenty-five cycles.

Life cycle assessment of three typical recycled products from construction and demolition waste

Environmental issues caused by the disposal of construction and demolition waste (CDW) is a worldwide problem. However, current studies lack a unified assessment of the reuse of CDW for quantifying the benefits in terms of the environment, economy, and carbon emissions. This study conducts a life cycle assessment on three typical recycled products manufactured from CDW: masonry bricks, permeable bricks, and thermal insulation blocks. The functional unit is 1 ton of CDW utilisation, and the system boundary is “cradle to gate”. The results indicate that the freshwater ecotoxicity, marine ecotoxicity, human carcinogenic toxicity, and human non-carcinogenic toxicity are the key categories of environmental impact. The mixing process is the key impact process, which accounts for more than 70% of each key environmental impact category. The cement and adhesive glue are the key impact materials. When considering the benefits of construction waste replacing traditional building materials, CDW recycled products can achieve significant environmental benefits and carbon reduction effects, which is decreased by at least 1.3 of normalised environmental impact and 15.6 kg CO2e under per functional unit.

Mechanical properties of PVC-based wood–plastic composites effected by temperature

Compared with traditional wooden building materials, polyvinyl chloride (PVC)-based wood–plastic composites have advantages of good weather resistance, easy processing capability, energy conservation, and environmental protection and have been popular and widely used in the field of civil construction and garden engineering in recent years. Due to the difference in the thermal expansion coefficient between its component materials, the stress will accumulate in the wood–plastic composites (WPCs) when the temperature changes, which will affect the mechanical properties of the material and structure. In order to explore the changes in mechanical properties of WPCs under different temperatures and achieve a safe and controllable design, the differential scanning calorimetry (DSC) method was used in this study to measure the glass transition temperature of the WPC between 78.45°C and 88.30°C, and the glass transition temperature (Tg) was about 83.54°C. The tensile, compressive, and bending mechanical property tests of PVC-based wood–plastic composite materials under different temperatures were carried out in the ambient temperature chamber to obtain the failure characteristics, the load–displacement curve, and the influence of temperature on their mechanical properties.

Mechanical and acoustical evaluation of bio-based composites made of cork granulates for acoustic ceiling tiles

This work is a study about new acoustic panels made of cork granulates coming from stopper by-products to be used as acoustic ceilings tiles, providing a sustainable and environmentally friendly alternative to traditional building materials. Cork granulates were bonded with water-based epoxy and acrylic resins. The obtained panels were acoustically and mechanically tested. The results showed values of sound absorption coefficient close to 0.50 and acceptable flexural strength for their use as suspended ceiling tiles. Therefore, these bio-based panels could be used as an alternative product to the traditional materials used for noise control applications inside commercial spaces like closed entertainment areas.

Review on manufacturing and fundamental aspects of laminated bamboo products for structural applications

LBPs are prepared in two ways either utilizing the roller pressed bamboo culm split (Zephyr mat) or preparing the bamboo strips with a wood planer. • LBPs are eco-friendly alternatives to traditional building materials. • LBPs’ mechanical properties are comparable to wood-based materials and concrete. • Bamboo’s chemical surface modification methods are promising in LBPs’ durability enhancement. Adverse effect of conventional construction materials on the environment has enforced researchers to use natural resources. Use of bamboo as a building material is increasingly becoming a popular topic of study in bio-composite research. Bamboo is highly renewable with better strength to weight ratio than conventional building materials and wood. Researchers have gained significant motivation in developing laminated bamboo products (LBPs), which can be used as beams and columns in the housing structure. This study presents the challenges and advantages of preparing LBPs to replace conventional construction materials. Firstly, the background and numerous applications of bamboo have been discussed. Then, different fabrication processes for LBPs have been discussed to comprehend their development challenges. Mechanical properties of the LBPs from multiple studies have been reviewed and analysed for their use in structural applications. To improve the deterioration of the bamboo, the authors have offered several points linked to their surface modification. In addition, future study in this field is mentioned as a source of inspiration for further advancement.

Performance and Measurement Devices for Membrane Buildings in Civil Engineering: A Review

Lightweight and flexible membranes offer different façades for buildings (suitability, competitive costs, durability, and other benefits) compared to traditional building materials. Increasing attention is being paid to membrane structures in the civil and industrial sectors. Acquiring response data or environmental characteristics directly from a model or building is the most straightforward approach to analyzing the properties of membrane structures, which also contributes to the development of theoretical studies and simulation methods along with the enactment of specifications. This paper provides a comprehensive overview of membrane structure performance, including mechanical, thermal, and energetic aspects, alongside the deployment and deflation of inflatable types. Furthermore, the devices used to monitor the structural response are summarized. The constitution of the structure is the most critical factor affecting its performance. A proper design would offer enhanced mechanical properties and thermal environments with a reduction in energy consumption. Non-contact measurement technology has the advantage of causing no structural disturbance and is low cost, but it lacks practical application in membrane buildings. The achievements and limitations of previous studies are also discussed. Finally, some potential directions for future work are suggested.

Evaluation of Frost Impact on Traditional Ceramic Building Materials Utilized in Facing Walls.

This paper takes into consideration the performance of traditional bricks as part of a building exterior wall finish. Exterior wall materials change their properties when exposed to external environment. This process is extended over time and its intensity is closely related to microstructure, moisture and freeze–thaw cycles. Two methods of freeze–thaw durability tests were used in this study: standard and defined by the authors. The authors’ method incorporated the actual conditions of masonry unit function in exterior wall finish, i.e., cyclical effects of precipitation water, changes in temperature and air humidity. The laboratory test study included 50 freeze–thaw cycles. Three characteristic ranges of pore dimensions were indicated in the analysis: below 0.1 µm, between 0.1 and 3.0 µm and above 3 µm. Based on the method of freeze–thaw durability testing, the areas of microstructure changes were determined. The obtained results were related to the absorption of ceramic building materials. The authors’ method confirms the usage of traditional ceramic building materials designed for use in protected walls against water penetration in unprotected exterior wall finish. The critical water saturation method of masonry units (standard) based on extreme environmental conditions generates significant changes in porosity distribution that do not reflect real, i.e., moderate, conditions. This method is appropriate for masonry units operating in severe conditions, i.e., F2. The aim of this study is to suggest a methodology for durability tests of traditional ceramic masonry units to cyclic freezing and thawing, which are only exposed to F1 (moderate) conditions during operation. Changes in the microstructure of the ceramic building materials were used as the primary evaluation criterion. In order to determine the effect of cyclic temperature changes, the freeze–thaw durability test was performed according to generally accepted standard procedures and in-house methodology. The purpose of the study is to point out the individual approach for the analysis of the material–environment system. At the same time, it should inspire researchers to innovative methods which use external conditions in a laboratory environment.