Conventional Construction Materials Research Articles

High-temperature behaviour of geopolymer composites containing carbon fibre and nano-silica: Mechanical, microstructure, and air-void characteristics

The fly ash–ground granulated blast-furnace slag-based geopolymer (FSG) represents a groundbreaking material, offering a sustainable and environmentally friendly alternative to conventional construction materials. This paper presents a systematic experimental study on FSG reinforced with carbon fibre (CF, 0%–1.0%) and nano-silica (NS, 1%–3%) at high temperatures (20, 200, 400, 600, 800, and 900 °C). Various tests concerning appearance, residual strength, uniaxial tension, XRD, FTIR, TGA, SEM, and air-void characteristics were conducted to analyse thermal effects. The findings show that as temperature increases, the colour of the geopolymer transitions from dark grey to yellow grey. Enhanced geopolymerisation during thermal solidification from 20 to 400 °C significantly increases the compressive, flexural, and tensile strengths of the geopolymer. The addition of CF and NS improves the residual strength of geopolymers at high temperatures, with optimal concentrations found to be 0.6% for CF and 2% for NS. CF maintains its bridging effect at high temperatures, enhancing fibre–matrix bonding, while NS promotes the formation of additional hydration products on CF surfaces, thereby strengthening the material further. After exposure to 800 °C, despite a weakening of the fibre–matrix interface, the modified geopolymers (FSGC0.6 and FSGC0.6N2) exhibit finer air bubble chord lengths and superior air-void characteristics than the control group. This supports the theory that the synergistic action of CF and NS not only enhances geopolymerisation but also fills pores, thus limiting crack propagation and densifying the pore structure.

3DP for sustainable built environment – Synthesis and thermomechanical characterization of composite materials based on local soil and date palm fiber waste

There is an increasing demand for sustainable construction materials to address the challenges posed by the environmental impact of the built environment (BE), which is driven by climate change, population growth, and urbanization. Conventional construction materials like cement contribute significantly to carbon emissions during production, transport, use, and disposal phases, and their poor thermal conductivity hinders efforts to maintain comfortable indoor environments. To address these challenges, there is an urgent need for innovative, locally sourced thermal insulation materials specifically designed for regions with extreme climates and high energy demands to maintain building comfort. This research explores synthesizing novel, environmentally friendly building materials using locally sourced date palm fiber waste and clay. The study also investigates the developed material's 3D printing (3DP) capabilities and optimizes its printing parameters with lab-scale prototypes. Additionally, thermo-mechanical characterization is conducted to assess its suitability for built environment applications. Different concentrations, from 1 to 5 wt% of date palm fiber to clay ratio (Dpf/C), were studied regarding microstructural, thermal, and mechanical properties, dimensional accuracy, and feasibility for 3DP of BE structures. Results demonstrated a significant reduction in thermal conductivity by 73%, achieving 0.244 W/mK, and an increase in compressive strength by 106%, reaching 10.9 MPa at 5 wt% Dpf/C. The promising thermomechanical properties of these composites and their suitability for 3DP support their use in real-world applications in the future's sustainable built environment. This scalable methodology can be adapted to regions with similar sustainable local and waste resources, advancing the circular economy.

Study on the effect of cinder ash as an auxiliary additive mineral in hydrated lime treatment for expansive sub-grade soil in road construction

Expansive soils pose significant challenges to road construction globally due to their tendency to expand and contract with changes in moisture content, leading to pavement failure. In the construction industry, finding an economical and cost-effective alternative to conventional road construction materials is crucial. The use of a natural cinder ash and hydrated lime mixture as reinforcement has proven to be effective in addressing this issue. Cinder ash, a readily available waste material in countries like Ethiopia, is adaptable and water-resistant, making it an ideal choice for reinforcing expansive soil. This article investigates the strength performance of a cinder ash and hydrated lime mixture as a reinforcement material for expansive soil. The study involves mixing 0%, 20%, 25%, 30%, and 35% of cinder ash with soil stabilized with 2–5% hydrated lime. Expansive soil samples are prepared according to the ASSHTO & ASTM method and tested for compressive strength, California bearing ratio, bulk density, and water absorption. The findings reveal a 448.62%, and 374% increase in compressive strength and California Bearing Ratio respectively for the specimen containing 5% hydrated lime and 35% cinder ash, cured for 28 days. The water absorption is minimized at 15.23% for the 5% hydrated lime and 35% cinder ash mixture; while the maximum density of the soil is observed at 1.774 kg/m3 for the optimal combination of 5% hydrated lime and 35% cinder ash mix. The study suggests that using 5% hydrated lime and 35% cinder ash content for the stabilization of expansive soil significantly enhances the strength characteristics of compressed stabilized soil.

The risk of shifting environmental burdens in biobased construction - Life cycle assessment of a residential renovated building case study in Belgium

Abstract The construction industry is a major contributor to environmental degradation, resource depletion, and energy consumption. As global concerns about sustainability and environmental impact continue to rise, it becomes imperative to reassess the materials used in building construction. This research paper presents a comprehensive life cycle assessment (LCA) using the Belgian TOTEM tool according to EN15804+A2 for evaluating material choices in building construction with a focus on the renovation of residential buildings in Belgium. The study aims to provide a holistic understanding of the environmental implications associated with biobased construction materials enabling informed decision-making for sustainable building practices. To achieve this, we conducted an analysis of the life cycle environmental performance of biobased materials used in external walls of a renovation case study project and compared it to common built-up scenarios of conventional construction materials applied in the same case study. The research results show that using biobased materials for renovation can significantly reduce embodied GHG emissions but can lead to burden shifting such as resulting in an increased impact on land use, particulate matter emissions, depletion of abiotic resources and eco-toxicity. The study not only underscores the importance of comprehensive cradle-to-grave life cycle thinking but also provides valuable insights for stakeholders in the construction industry.

Effect of waste travertine powder on properties of rhyolitic tuff-based geopolymer

This investigation explores the potential of geopolymer technology as an eco-friendly substitute for conventional construction materials by emphasizing the innovative use of naturally occurring green rhyolitic tuff and repurposed travertine powder in geopolymer paste formulations. Replacement levels of tuff with travertine at 40 %, 45 %, and 50 %, along with an alkaline solution with a NaOH molarity range of 8.2 M–22.1 M, have been analyzed for their impact on flowability, water absorption, porosity, compressive strength, and unit weight of the geopolymers over curing periods of 2, 28, and 90 days. The flowability measurements show that adding 40 %, 45 %, and 50 % travertine leads to approximately 7 %, 31 %, and 31 % reductions in the flowability of the geopolymer, respectively. It is demonstrated that adding 40 % travertine significantly improves the geopolymers’ compressive strength with an 11.5 M NaOH concentration, showing substantial increases of approximately 15.5, 9.0, and 2.4 times at the curing duration of 2, 28, and 90 days, respectively, relative to the geopolymer without travertine. As an optimum points, an 18.5 M NaOH and an 0.7 solution-to-powder ratio decrease the long-term apparent porosity and water absorption of the geopolymer without travertine by about 14 % and 19 % compared to those at the same solution-to-powder ratio with 11.5 M NaOH, respectively. Microscopic examinations were employed to validate the development of sodium aluminosilicate hydrate, calcium aluminosilicate hydrate, and calcium silicate hydrate gels, underscoring the advantageous contribution of the elevated CaO content in the travertine to the geopolymer matrix. This research not only highlights the environmental benefits of repurposing waste materials but also contributes to the development of more sustainable and durable geopolymer pastes, offering a promising approach to enhancing environmental stewardship in material science practices.

Environmental Impact Assessment of Using Vernacular Materials for Sustainable Developments: Insights from an Eco-Sensitive Resort in India

It is known that quantification of embodied carbon and associated carbon emissions of different building types gives indications of the environmental impact of a structure during its construction, operation, and demolition stages and the various levels of boundary conditions within the framework of life cycle analysis (LCA). In this context, this study examines an eco-sensitive resort, located in a warm and humid climate. It conducts a comparative assessment of embodied carbon and resultant carbon emission by using conventional and alternative vernacular construction materials for foundation, superstructure, walling, roofing, flooring, joinery, finishing details, and site-work. The research method includes calculation of total quantum of materials used in the selected eco-sensitive resort project with one case scenario of using conventional construction materials and another case scenario of using their vernacular alternatives for all the different blocks with MS Excel© tool. The resultant values of their embodied carbon and carbon emission are calculated by using the globally recognized database and other calibrated LCA tools. The results show that in the high-end cottages with conventional brick and RCC construction systems, the superstructure and finishing cause the major amount of energy consumption during the construction stage. Using alternative vernacular materials like bamboo in the super structure, local tandoor stones in flooring reduce the embodied energy and carbon emission level significantly. The assessment shows that a 38.8% reduction can be achieved in embodied energy. The carbon emissions decrease by 1680 MT if vernacular materials are used. This finding is useful for building owners and designers in selecting holistic and environmentally sustainable building materials to produce sustainable buildings.

A life cycle carbon dioxide equivalent emissions assessment of zero carbon building in hot semi-arid climate region: Case study

As societies are shifting toward carbon neutral environments, they are beginning to account for their carbon emissions. One of the primary contributors of greenhouse gas emissions and global warming is the building industry; therefore, Life Cycle Assessment (LCA) is one of the instruments that allows an assessment of the energy and the energy-related environmental impacts of the buildings from cradle to grave, according to ISO 14040. In this context, the aim of this research study is to assess the Life Cycle carbon dioxide (LC CO2eq) emissions over a 50-year-lifespan of a zero-carbon solar-powered earth-based building, built with carbon-free adobe bricks, in the hot semi-arid climate of Morocco. While research on the carbon dioxide equivalent (CO2eq) emissions across the life cycle is crucial to determine the energy-intensive stages, this study looks into global tendencies of CO2eq emissions arising during the cradle-to-gate embodied (A1-3) and operational (B6) phases of a Zero Carbon Building (ZCB) case study, and which should be offset by carbon-free energy in order to abide by the ZCB definition. Results show that the LC CO2eq emissions of the eco-friendly zero-carbon residential building falls in 48.62 Kg CO2eq/m2.y., with an operational phase that has a share of around 93 % of global LC CO2eq emissions. In addition, when conventional construction materials such as concrete, bricks, and insulation materials are used as an alternative, embodied carbon emissions accounts for 6.3 kg CO2eq/m2.y. and is 85 % higher than the eco-friendly building, and it constitutes approximately 12.5 % of the overall carbon footprint. Moreover, the annual embodied and operational CO2eq emissions are offset by the 3.3-kWc-building-added-photovoltaic system. Hence, the conducted case study offers valuable insight into the good practices for decarbonization of Morocco's building stock.Through that case study, we aim to generate knowledge of net zero carbon buildings within the African continent, promoting the perks of decentralized solar energy in leaping forward a carbon-free electrified continent and valorizing the local construction techniques and knowhow in the building sector.

WITHDRAWN: From Debris to Innovation: Unveiling a New Frontier for Alkali-Activated Materials

Alkali-activated materials (AAMs) play a crucial role in addressing the environmental challenges of traditional construction binders by offering a lower carbon footprint alternative. Industrial by-products are utilized, reducing waste and energy consumption associated with lime and cement production. AAMs represent a sustainable innovation in the construction industry, promising significant reductions in CO2 emissions and resource utilization. This review aims to meticulously analyze the existing body of research on the potential of Construction and Demolition Waste (CDW) as an alternative precursor for producing AAMs. This review study introduces a novel angle by critically evaluating advancements in CDW processing techniques for AAM production, alongside assessing the environmental and mechanical outcomes. It pioneers bridging the gap between innovative recycling methods and sustainable construction practices. The ultimate goal is to synthesize findings into a comprehensive framework to guide future research toward optimizing CDW utilization in AAM production, thereby contributing to sustainable construction practices and the circular economy. This study stands out for its in-depth examination of CDW's role in mitigating the environmental impact of conventional construction materials, offering novel insights into the path toward sustainability in the construction industry. By critically assessing the latest advancements in CDW processing techniques and their environmental and mechanical implications, the study not only underscores the potential of CDW in revolutionizing the construction industry but also sets a new precedent in sustainability research. It bridges the crucial gap between theoretical innovation and practical application, offering actionable insights for optimizing CDW utilization in AAM production. This comprehensive analysis signifies a pivotal step towards integrating sustainable practices within the construction sector, advocating for a paradigm shift towards a circular economy that prioritizes resource efficiency and environmental stewardship.

Natural Fiber-Reinforced Mycelium Composite for Innovative and Sustainable Construction Materials

Fiber-reinforced mycelium (FRM) composites offer an innovative and sustainable approach to construction materials for architectural structures. Mycelium, the root structure of fungi, can be combined with various natural fibers (NF) to create a strong and lightweight material with environmental benefits. Incorporating NF like hemp, jute, or bamboo into the mycelium matrix enhances mechanical properties. This combination results in a composite that boasts enhanced strength, flexibility, and durability. Natural FRM composites offer sustainability through the utilization of agricultural waste, reducing the carbon footprint compared to conventional construction materials. Additionally, the lightweight yet strong nature of the resulting material makes it versatile for various construction applications, while its inherent insulation properties contribute to improved energy efficiency in buildings. Developing and adopting natural FRM composites showcases a promising step towards sustainable and eco-friendly construction materials. Ongoing research and collaboration between scientists, engineers, and the construction industry will likely lead to further improvements and expanded applications. This article provides a comprehensive analysis of the current research and applications of natural FRM composites for innovative and sustainable construction materials. Additionally, the paper reviews the mechanical properties and potential impacts of these natural FRM composites in the context of sustainable architectural construction practices. Recently, the applicability of mycelium-based materials has extended beyond their original domains of biology and mycology to architecture.

Flexural behavior of singly curved GFRP sandwich panel with polyurethane foam core

Curvilinear architecture and structures are becoming a worldwide trend for its streamlined appearance and synchronicity with the surroundings. Nonetheless, the conventional construction materials might not be able to achieve the desired curvilinear geometries in an effective and economic manner. In this regard, glass fiber-reinforced polymer (GFRP) curved sandwich panel with polyurethane foam core is able to meet the requirement of the construction efficiency and economy as well as satisfy the need for a lower energy consumption. However, few studies are available on the mechanical behavior of such panels. In this regard, this work was to conduct an experimental and numerical investigation on the singly curved GFRP sandwich panels to evaluate the flexural performance. In particular, the effect of the foam density, inclined angle, core thickness and stacking sequence of face sheet on the load-carrying capacity and failure mode was addressed. Four failure modes were identified. The singly curved GFRP sandwich panel showed an improved stiffness when compared to the flat panel, but showed more complicated failure mechanism. The stiffness of the curved panel with inclined angle 30° was 250 % higher than that of the flat panel in the test results. It was shown that the strength and stiffness increased as the density and thickness of the foam core increased. In addition, a finite element analysis was conducted via MSC.Marc and validated by the experimental results. A parametric study was performed to address the design parameters. It was found that the specimens with inclined angles of 30° and 45° showed the greatest stiffness.

Fast-Growing Bio-Based Construction Materials as an Approach to Accelerate United Nations Sustainable Development Goals

The United Nations Sustainable Development Goals (UN SDGs) ensure future human well-being. However, they face challenges due to the pressing need to reduce carbon emissions, with nearly 40% originating from the construction sector. With the current global environmental and energy crisis, there is a pressing need to address building carbon emissions and prioritise investments in passive strategies for improving indoor thermal comfort. Exploring fast-growing bio-based materials like bamboo, straw, hemp, and flax directly addresses these concerns, fostering environmental sustainability. Material selection in construction is crucial for advancing the SDGs, for example, promoting sustainable cities and communities (SDG11) and responsible consumption and production (SDG12). This paper proposes a comparative analysis of conventional and bio-based construction materials, focusing on their production stages through life cycle analysis. Tools such as Building Emissions Accounting for Materials (BEAM) and the Methodology for Relative Assessment of Sustainability (MARS) enable a detailed comparison. The results highlight the benefits of bio-based materials in storing carbon more rapidly and their lower environmental impact compared to conventional alternatives. Moreover, bio-based materials contribute to indoor moisture regulation and a healthier indoor environment, underscoring their potential to accelerate progress towards the UN SDGs through informed material choices in design practices.

A study on the thermal performance of Pleurotus Ostreatus/Straw mycelium composites and its application in building envelopes

Most conventional construction materials are non-degradable, putting huge burden on our environment at disposal. Mycelium-based composites are formed by aggregating some forestry and agricultural residues with networks of filamentous hyphae, and they are degradable and environmentally friendly. The paper examines the thermal property of Pleurotus Ostreatus/Straw (PO/S) mycelium composites and explores the possibility of using it for building insulation application. Samples of PO/S mycelium composites of different composition and density were prepared. The thermal conductivity was measured by a steady-state thermal measurement approach. It was found that incubation time, preparation method, and composition are important factors for the thermal performance of the material. The lowest thermal conductivity was 0.12 W/m‧K, with the sample (FMC 04) consisting of 75 % Pleurotus Ostreatus primary spawn and 25 % straw substrate and prepared without pressure. With this composition, a series of mycelium-based façade and roof sandwich insulation panels were designed in details. The U-values of the panels were calculated using THERM software, and required panel thickness was investigated. It was found that when the panel thickness reaches 240 mm, two types of wall panels (W1 and W2) and two types of roof panels (R1 and R2) satisfy the energy efficiency requirements of Class A public building in the “hot summer and cold winter” climate zone in China. A cost-benefit analysis shows that implementation of this novel insulation panel is financially sustainable for at least 10 years from now on, if it is sold at a price 5 % more than normal panels.

Potential environmental impact of mycelium composites on African communities

The ecological and economic benefits of mycelium composites offer a promising opportunity for supporting sustainable development in Africa. This study focuses on assessing the environmental impact of mycelium composites for building and construction (MCBs) by conducting a life cycle assessment (LCA) in the context of Africa. It is demonstrated that the potential environmental impact of MCBs is substantially influenced by the use and source of electrical power for autoclaves, incubators, and ovens, making the culturing and post-processing phases the major environmental hotspots. The impact of MCB production is also relative to the energy mix of specific countries, being higher in countries that rely on fossil fuel energy (e.g., South Africa) and lower in those that rely more on renewable sources (e.g., Democratic Republic of the Congo, DRC). Furthermore, the impact of MCB production is found to be sensitive to travel distance, suggesting that situating production facilities closer to agricultural, agro-industrial, and/or forestry waste sources could be more beneficial than interregional sourcing, for example. It is also demonstrated that MCBs have the potential to be a more ecologically sustainable alternative to some conventional construction materials (e.g., concrete) over an entire life cycle. Based on the insights obtained from this LCA, some recommendations have been proposed to address potential environmental repercussions pre-emptively and proactively: this is particularly important for nations, mainly in the Global South, that exhibit low resilience to climate change due to limited economic resources. Furthermore, with the rapid expansion of mycelium composite technology, there is a need to increase awareness about its potential environmental impact and, ultimately, to mitigate its potential contribution to pressing environmental concerns (e.g., global warming and climate change). Consequently, this study also adds to the existing body of literature on LCA studies, delineating key factors for consideration in future LCA studies and providing guidance for the sustainable establishment and expansion of this technology.

Creating sustainable and flexible architectural skin with microbial cellulose-based material: synthesis and mechanical characterization

AbstractAttaining sustainability by developing efficient architectural materials will be a suitable remedy for various environmental problems. Incorporating clean biotechnology, particularly Bacterial Cellulose (BC), into the field of Architecture Design offers a novel strategy with the objective of creating environmentally-friendly architectural materials. The key goal of this research is to investigate the synthesis of BC by cultivating kombucha SCOBY in a culture medium that has been supplemented with sugar and tea extract. The linear density, tensile strength and strain of the BC bio-film and BC composites were assessed in order to determine the material’s degree of fitness in potential applications. The tensile test showed that BC bio-film and its jute composite had tensile strengths of 5 MPa and 10 MPa respectively, indicating notable resilience and durability as a feasible substitute for conventional construction materials. The study delves deeper into the sustainability, biodegradability, and economic feasibility of BC, emphasising its potential as an independent foundational material. The incorporation of jute fibres into BC enhances its capabilities, resulting in the development of a novel composite material known as BC + jute. This composite exhibits superior mechanical and psychochemical characteristics, making it suitable for the creation of sophisticated architectural prototypes. The results of this research establish a strong foundation for the advancement of ecologically conscious architectural solutions, demonstrating the feasibility and capacity of BC in promoting sustainability within the construction sector.Keywords: Microbial Cellulose, Scopy, Architecture, Environmental-friendly, sustainability, interior design, jute fiber, biomaterials.

Valorizing inherent resources from waste streams for in-situ CO2 capture and sequestration in the steel industry

The imperative need for decarbonization within the energy-intensive steel industry, a pivotal sector for meeting global warming mitigation targets, underscores the significance of deploying cost-effective CO2 capture and sequestration (CCS) measures. The substantial external costs and resource consumption associated with traditional CCS methods present practical challenges. Here, we proposed a pragmatic strategy to integrate CCS into the steel industry through recycling inherent resources from steelmaking waste streams for in-situ CCS (ICCS). The composites prepared from blast furnace slag (BFS) and steel slag (SS) demonstrated the capacity to capture a maximum of 2.77 mol/kg of CO2 from the simulated flowing flue gas at 75 °C, and the energy required could be sourced from steelmaking waste heat. Comprehensive characterizations revealed the evolution of phase compositions and pore structures in different BFS/SS-incorporated composites, providing insights into accelerating the carbonation by elevating temperatures and SS dosages. Notably, ICCS strategy was validated to offer significant potential in CO2 emission reduction (up to −570.0 kg CO2e/t) normalized by compressive strength of the conventional construction materials. Overall, ICCS strategy can minimize the external resource consumption and additional units for implementing collaborative waste recycling in the steel industry with significant environmental benefits.

Sustainable construction materials for low-cost housing: Thermal insulation potential of expanded SBR composites with leather waste

In recent years, there has been a growing interest in improving energy efficiency and thermal comfort in low-income housing, especially in regions prone to extreme climatic conditions. Conventional construction materials such as bricks and concrete exhibit shortcomings in energy efficiency, resulting in high indoor temperatures. This scenario not only impacts residents' well-being but also increases energy consumption, especially for air conditioning systems, potentially straining the electrical infrastructure in hot climate areas, leading to power outages and adverse consequences for the community and local industry. This study proposes an innovative and sustainable solution: the use of expanded styrene-butadiene rubber (SBR) with micronized leather shavings, possessing thermal insulation properties. The thermal insulation capacity of the composites was evaluated using heat flow methods, hot/cold plate heat flow analysis, and impedance tube acoustic method. The SBR/Leather waste composite at 20 phr emerges as a viable, promising, and sustainable alternative, exhibiting significant thermal insulation capacity with a thermal conductivity of 0.073 Wm-1.K−1 and temperature attenuation close to 15 °C, potentially enhancing comfort and quality of life in urban areas. The thermal insulation results of the other composites also surpassed traditional construction materials such as building boards, plywood, fiberglass, asphalt roofing, and cement tiles. The study demonstrates the feasibility of reusing leather as a reinforcing filler in rubber-based foams to produce thermal insulation materials, offering a sustainable solution to mitigate urban heating and improve quality of life in cities.

Simulation and Mitigation of the Carbon Footprint from Conventional Construction Materials and Replacement with Alternative Materials

Objetivo: O objetivo foi analisar quais impactos ao meio ambiente, provenientes da construção de residenciais, realizando uma simulação da pegada de carbono desse empreendimento e elaborando um comparativo com a substituição de materiais convencionais para materiais alternativos na mitigação de Dióxido de carbono (CO2). Referencial Teórico: A contribuição efetivamente da indústria da construção civil na emissão dos GEE, devido extração de materiais, transporte dos mesmos e processo de fabricação do cimento. O setor é encarregado pela produção de um bem que possui uma longa vida útil, assim, é possível perceber que a emissão dos gases tem um papel crítico ao meio ambiente Método: A metodologia foi dividida nas seguintes etapas: pesquisa bibliográfica, com ênfase nos temas; coleta de dados, que foram levantados a partir de trabalhos em campo e a utilização de geoprocessamento com dados oriundos do sensoriamento remoto; análise dos impactos ambientais e o comparativo de materiais convencionais para materiais alternativos. Resultados: Comprovou-se nos resultados dos materiais construtivos que, comparando os valores de 212,83 kgCO2 e 208,14 kgCO2, respectivamente, de CO2 emitido pelos cinco materiais escolhidos, chegou-se a um total de redução de 4,69 kgCO2, ou seja, o equivalente a 2,2% a menos de CO2 emitido por cada casa, se substituídos as telhas cerâmicas e os tijolos cerâmicos por bambu. Implicações da pesquisa: Os resultados deste trabalho são de grande relevância para o desenvolvimento sustentável na construção civil, não só apenas do município de Garanhuns, mas em todo Agreste meridional, trazendo para o interior de Pernambuco possibilidades de mitigar as emissões de gases. Originalidade/valor: Utilizando o conhecimento técnico e as emissões dos materiais construtivos utilizados no Brasil, espera-se contribuir de forma relevante para a problemática que se apresenta, pois a construção civil como um todo, necessita de mudanças em sua forma de emitir gases do efeito estufa, já que é um setor com um alto potencial de mitigar os efeitos causados pelas emissões de GEE emitidos pelos seus materiais construtivos.

An Experimental Study of Concrete Mixed with Coconut Shell as Partial Replacement of Course Aggregate

The high cost of conventional construction materials affects the economy of structure. The possibility of utilizing recycled coconut shell aggregates in concrete as coarse aggregate is examined in the present study. An optimum percentage replacement of coarse aggregate with coconut shell aggregate is determined from the study. Coconut shell is a lightweight material thus producing lightweight concrete. The replacement of coarse aggregate of coconut shell by 10%, 20% and 30%. The Design mix used is M20 grade and testing of specimens are conducted after 7 and 28 days of curing. The flexural and compressive strength of concrete are tests. The main objective is to encourage the use of these waste products as construction materials in low-cost housing Aggregate is a major ingredient for making concrete, occupying almost 70-80% part of concrete. Conventionally crushed rocks are used as coarse aggregate and river sand as fine aggregate. Both are naturally available materials. Due to the speedy growth of construction works, conventional aggregate sources are exhaust very fast leading to a significant increase in the cost of construction. For sustainable development, these materials should be used wisely and alternative materials need to be searched to replace regular aggregate. A large number of studies have been done to search for alternative materials for the production of concrete. At the same time due to fast industrialization, production of waste material is increasing day by day. Its disposal has become a real problem. It can be concluded that the ideal amount of coconut shell replacement for coarse aggregate for M20 Concrete is 10% -20%. Key Words: Concrete Mix, Coconut shell, Low cost housing, Flexural strength, Compressive strength, Design mix, Replacement of Course Aggregate.

Effect of partial delignification and densification on chemical, morphological, and mechanical properties‏ of wood: Structural property evolution

Efforts have been dedicated to developing sustainable alternatives for conventional construction materials, resulting in the development of densified wood as an innovative, environmentally friendly, and high-performance material. This study focuses on investigating the effects of treatment parameters (e.g., partial delignification boiling time, chemical concentrations, and hot-pressing pressures) on the chemical, morphological, and mechanical properties of the densified wood. Results revealed that the partial delignification process of low-density Balsa wood reduced lignin content by 50–80%, which enhanced the crystallinity of the wood by 21–54%. However, prolonged periods of partial delignification caused a degradation in the crystalline regions in wood. The modulus of rupture (MOR) and modulus of elasticity (MOE) of the densified wood samples increased by 90–680% and 10–810% compared with those of the raw wood samples, respectively. The MOR of the densified wood also showed a dependency on lignin content and porosity. An optimal lignin content of approximately 10% was associated with the highest MOR in densified wood. Moreover, the relationship between the MOR and porosity suggested that the MOR improvement occurred in two stages. The first stage of MOR improvement is controlled by the reduction in the porosity and the second stage is controlled by the improved hydrogen bonding among cellulose nanofibrils.

Mechanical Properties of Concrete Containing Coconut Shell as Coarse Aggregate Replacement

The increase in the price of traditional construction materials is a serious issue. Concrete, which is made of cement, sand, coarse aggregate, and water, is widely used as a building material. However, an increase in concrete production has certain negative consequences for the environment, such as the extraction of natural resources such as aggregate. Therefore, innovation in concrete materials without neglecting strength can always be done. Coconut shells are one of the recycled materials that can be used as a replacement for conventional construction materials such as aggregate. The aim of this research is to investigate the properties of concrete by using coconut shell as a partial replacement for coarse aggregate. A total of 60 samples with 0%, 10%, 20% and 30% of coconut shells as coarse aggregate for concrete replacement were cast. The properties of fresh and hardened concrete with coconut shell as coarse aggregate replacement were determined at 7, 14, and 28 days of curing ages. The results showed that concrete with coconut shell as a coarse aggregate replacement had a positive impact on workability, porosity, density, and UPV but not on compressive and tensile strength. However, the concrete made from coconut shell aggregates satisfied the minimum requirements of normal concrete, resulting in the acceptable strength required for M30 grade concrete. It can be used as lightweight concrete. Using coconut shell as a replacement for aggregate is not only cost-effective and environmentally friendly, but it also helps solve the problem of conventional material shortages, such as coarse aggregate. It can also help to solve the problem of waste disposal.