Sustainable Construction Materials Research Articles

Establishing the Characteristic Compressive Strength Parallel to Fiber of Four Local Philippine Bamboo Species

Bamboo is considered a sustainable construction material due to its ability to grow quickly and its mechanical properties that are comparable to timber. Contributing to the current effort to establish structural bamboo standards in the National Structural Code of the Philippines (NSCP), this study establishes the characteristic compressive strength of four bamboo species: Bambusa vulgaris (36 samples), Dendrocalamus asper (36 samples), Bambusa blumeana (94 samples), and Guadua angustifolia Kunth (30 samples). The samples were subjected to compressive loading following ISO 22157-1 (2017). The characteristic compressive strength values obtained, according to ISO 12122-1 (2014), were 40.35 MPa for B. vulgaris, 40.21 MPa for D. asper, 46.63 MPa for B. blumeana, and 36.99 MPa for G. angustifolia Kunth. Simple linear analysis, one-way ANOVA, and Welch’s t-test were used to analyze the correlation models and establish a comparative analysis of the effects of nodes and geometric and physical properties on the compressive strength of bamboo samples. In comparisons of the characteristic compressive strengths obtained from this study to the strengths of unseasoned structural timber of Philippine woods, all bamboo species showed higher strength values than did other woods, and bamboos thus have great potential as an alternative construction material to timber.

Behaviour of short and long columns made from bamboo scrimber subjected to uniaxial compression

Engineered bamboo has been getting recognition as a forerunner in terms of desirable mechanical properties and a sustainable construction material. One of the most widespread variants is bamboo scrimber, also known as Parallel Bamboo Strand Lumber (PBSL). This paper presents a holistic investigation into the uniaxial compressive capacity of short bamboo scrimber columns in terms of failure mode, size effect, aspect ratio and failure strain. The studies in focus have been collated from published articles in literature. Furthermore, intermediately slender to long columns have been investigated with respect to the most common international timber standards and, elastic and inelastic theories. It is shown that the dominant failure mode affects the ultimate strength, especially a failure mode called kinking/local buckling. A size effect was observed and discussed with respect to the failure modes. In addition, a tangent modulus theory was proposed from a constitutive model called the Full-range Ramberg Osgood model that could better predict the critical buckling stress of intermediate-long columns over the conventional theory. Moreover, a modified AS1720 design approach was proposed to accommodate the inherent column behaviour of bamboo scrimber. Finally, a modified Newlin-Gahagan approach was proposed which produced consistent predictions for the experimental buckling stress for columns with varying slenderness across four different studies.

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 ºC, 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.

Behaviour of sewage sludge based lightweight aggregate in geopolymer concrete

The global challenge of sewage sludge disposal has encouraged innovative solutions aimed at reducing environmental impact while simultaneously addressing the growing demand for sustainable construction materials. This study aimed to develop treated raw sewage sludge-based lightweight aggregates with strength comparable to commercially available aggregates. Two methods, namely cold bonding and sintering, were employed for the formation of aggregates. The sintering method produced well-formed and hard aggregates, while the cold bonded aggregates exhibited weakness and disintegrated under the slightest pressure. The optimal mix for quality aggregates was found to be 10%–20% sewage sludge, 70%–80% fly ash, and 10% lime using the sintering method. In the sintering method, an increase in sewage sludge content resulted in the reduction of bulk density and specific gravity by 13% and 4% respectively due to the high organic content in sewage sludge, volatile gas release, and porous structure formation. When 10% to 20% sewage sludge content was added, water absorption of the aggregates also increased by approximately 2%. Physical properties such as individual pellet strength. aggregate crushing value reduced by 18%, 20% respectively and the aggregate impact value increased by about 9%. These aggregates were then used to produce lightweight geopolymer concrete, which exceeded the design strength by 7% for the aggregate containing 20% sewage sludge and demonstrated excellent physical properties. The use of waste-based aggregates offers advantages including savings in cost, sustainability, resource conservation, waste reduction, and reduced environmental impact, making them a valuable alternative to natural crushed stone aggregates in specific applications.

Investigating interphase bond behavior of waste badminton string fiber in composite matrix

ABSTRACT Recently moving towards the usage of sustainable and renewable construction materials, the badminton strings are identified as alternate material for commercial fibers. These recycled badminton strings once discarded from the racquets become a waste and cannot be reused. Hence investigation of the interphase bond behavior of these fibers with the cement and epoxy polymer matrix plays a major role. Therefore, the pullout mechanism between the fibers with the epoxy matrix is examined using the photoelasticity technique with a 40 mm embedment length. Whereas the pullout mechanism between the fibers with the cementitious matrix is examined for a single string of fiber using a pullout test with varied embedment lengths of 10, 20, 30, 40, 50, 60, 70, and 80 mm. From the study, the minimum and maximum bond stress between the fiber and epoxy interface is 3.23 MPa and 11.59 MPa respectively. Whereas between the fiber and cementitious interface, the minimum and maximum bond stress is 1.02 MPa and 2.15 MPa respectively. The experimental results are validated by the Weibull modulus approach which shows less variability. Thus, the results of the pullout test in composite matrix recommend the usage of waste badminton strings in fiber-reinforced concrete applications.

Research on Statistical Characteristics and Prediction Methods of Ferronickel Slag Pervious Concrete Performance with Different Sizes of Aggregate and Mixtures

In the exploration of sustainable construction materials, the application of ferronickel slag (FNS) in creating pervious concrete has been investigated, considering its potential to meet the dual requirements of mechanical strength and fluid permeability. To elucidate the statistical properties and models for predicting the performance of FNS-composited pervious concrete with different sizes of aggregates and mixtures, a series of experiments, including 54 kinds of mixtures and three kinds of aggregate, were conducted. The focus was on measuring the compressive strength and the permeability coefficient. The results indicate that the compressive strength of pervious concrete decreases with the increase in aggregate size, while the permeability coefficient increases with the increase in aggregate size. Through normalization, the variability of these properties was quantitatively analyzed, revealing coefficients of variation for the concrete’s overall compressive strength and the permeability coefficient at 0.166, 0.132, and 0.150, respectively. Predictive models were developed using machine learning techniques, such as Linear Regression, Support Vector Machines, Regression Trees, and Gaussian Process Regression. These models demonstrated proficiency in forecasting the concrete’s compressive strength and permeability coefficient.

The influence of nanosunflower ash and nanowalnut shell ash on sustainable lightweight self-compacting concrete characteristics

The absence of biodegradability exhibited by plastics is a matter of significant concern among environmentalists and scientists on a global scale. Therefore, it is essential to figure out potential pathways for the use of recycled plastics. The prospective applications of its utilisation in concrete are noteworthy. The use of recycled plastic into concrete, either as a partial or complete substitution for natural aggregates, addresses the issue of its proper disposal besides contributing to the preservation of natural aggregate resources. Furthermore, the use of agricultural wastes has been regarded as a very promising waste-based substance in the industry of concrete manufacturing, with the aim of fostering the creation of an environmentally sustainable construction material. This paper illustrates the impact of nano sunflower ash (NSFA) and nano walnut shells ash (NWSA) on durability (compressive strength and density after exposure to 800 °C and sulphate attack), mechanical properties (flexural, splitting tensile and compressive strength) and fresh characteristics (slump flow diameter, T50, V-funnel flow time, L-box height ratio, segregation resistance and density) of lightweight self-compacting concrete (LWSCC). The waste walnut shells and local Iraqi sunflower were calcinated at 700 ± 50 °C for 2 h and milled for 3 h using ball milling for producing NSFA and NWSA. The ball milling succeeded in reducing the particle size lower than 75 nm for NSFA and NWSA. The preparation of seven LWSCC concrete mixes was carried out to obtain a control mix, three mixtures were created using 10%, 20% and 30% NWSA, and the other three mixtures included 10%, 20% and 30% NSFA. The normal weight coarse aggregates were substituted by the plastic waste lightweight coarse aggregate with a ratio of 75%. The fresh LWSCC passing capacity, segregation resistance, and filling capability were evaluated. The hardened characteristics of LWSCC were evaluated by determining the flexural and splitting tensile strength at 7, 14 and 28 days and the compressive strength was measured at 7, 14, 28 and 60 days. Dry density and compressive strength were measured after exposing mixes to a temperature of 800 °C for 3 h and immersed in 10% magnesium sulphate attack. The results demonstrated that the LWSCC mechanical characteristics were reduced when the percentages of NWSA and NSFA increased, except for 10% NWSA substitution ratio which had an increase in splitting tensile strength test and similar flexural strength test to the control mixture. A minor change in mechanical characteristics was observed within the results of LWSCC dry density and compressive strength incorporating various NSFA and NWSA` contents after exposing to temperature 800 °C and immersed in 10% magnesium sulphate attack. Furthermore, according to the findings, it is possible to use a combination of materials consisting of 10–20% NSFA and 10–20% NWSA to produce LWSCC.

Impacts of synthesis variables on spectroscopics evaluation of biobased fatty amide as alkylammonium salt’s precursor for perovskite

Ammonium salts are widely used in chemical industries as additives in cement industries, phase change materials in thermal cooling, ionic materials in electrochromic window and multifunction medium/precursor/catalyst in solar cells to improve the efficiency and stability. This work introduces a procedural enhancement by incorporating a liquid-liquid extraction purification process, resulting in a high-purity biobased fatty amide (FA) with tri-substitution and high-purity biobased tetraalkylammonium ammonium salt (TAS). Biobased FA derived from renewable sources was synthesized via an amidation reaction between fatty acids from vegetable oil with tris(3-aminopropyl)amine under reflux conditions, producing a precursor for TAS used in perovskite solar cell (PSC). This study aimed to optimize and determine the reaction condition of biobased FA at various key synthesis variables by investigating the effects of solvent selection, reaction and crystallization, temperature, catalyst, mole ratio, and dehydrating agent on synthesis yield. A multiple liquid-liquid extraction process was employed to enhance the purity of biobased FA by tunning the selection of solvent based on its relative polarity of the reactant and products. Response surface methodology (RSM) and central composite design (CCD) were utilized to optimize the total yield and the three key variables (reaction time, crystallization time, catalyst amount) respectively. The experimental model developed in this study demonstrated a high degree of fitness with the experimental data (F-value = 27.34), p-value < 0.05) and nonsignificant lack of fit. The model predicted a maximum synthesis yield percentage of 52.62 % under optimal conditions (reaction and crystallization time of 12 and 28 hours), respectively with 4.47 % catalyst). The coefficient of determination of R2 = 0.98 shows a high correlation with the predicted values and in good agreement with the experimental values. Physicochemical properties analysis using spectroscopies techniques, confirmed improved purity with 100% abundance yield of tri-substitution biobased FA and enhanced TAS’s purity up to 60%. The optimization study sheds light on the impact of key synthesis variables on the synthesis yield and percentage abundance (purity), advancing the development of more efficient and tailored sustainable construction materials. These findings highlight the potential of using biobased FA as a sustainable source for TAS production, contributing to a more environmentally friendly approach in PSC development.

Flexural Response of Functionally Graded Rubberized Concrete Beams.

Recycling rubber and/or steel fiber components of waste tires in construction applications is a venue for maximizing the recycling rate of these items. Additionally, it supports the move towards producing sustainable construction materials and conserving natural resources. Previous research explored the viability of employing recycled waste rubber particles as an alternative for natural aggregate. Despite the adverse effect of rubber on the mechanical properties of concrete (e.g., lower compressive strength), it produces several advantages, including excellent dynamic and ductility properties, which can be utilized in structural members critical to dynamic loads, e.g., blasts, earthquakes, and impacts. In an effort to expand the adoption of waste rubber in concrete beams and to eliminate key concerns associated with the degradation of their flexural behavior, the functionally graded (FG) beams concept was utilized. The present investigation comprised the testing of five beams using a four-point bending configuration. Plain concrete, rubberized concrete (RuC), and steel-fiber reinforced rubberized concrete (SFRRuC) beams were cast along with FG beams arranged in two layers. The top layer of the FG beams comprised plain concrete, while the bottom layer consisted of RuC or SFRRuC. Experimental findings indicated that the flexural behavior of the FG beam with layers of SFRRuC and plain concrete exceeded the flexural strength, displacement ductility ratio, and toughness performances of the plain concrete beam by 9.9%, 12.9%, and 24.4%, respectively. The moment-curvature relationship was also predicted for the tested beam and showed an excellent match with the experimentally measured relationship.

Investigation into the strength and toughness of polyvinyl alcohol fiber-reinforced fly ash-based geopolymer composites

This study investigates the influence of polyvinyl alcohol (PVA) fiber dosage and length on the porosity, mechanical strength, and toughness of fly ash-based geopolymer composites. The experimental data are analyzed to examine the deflection-load relationship in the flexural toughness tests of fiber-reinforced geopolymer composites (FRGPC) with different PVA fiber parameters. The results indicate that the addition of a certain amount of PVA fibers effectively enhances the flexural resistance of FRGPC. Particularly, the optimal performance is achieved with the addition of 2.0 vol% of 9 mm PVA fibers, where the 28-day flexural strength reaches 13.16 MPa, representing a 150.95 % increase compared to the control group, and the deflection at peak load increases by 308.00 %. However, the compressive strength of FRGPC with PVA fiber dosage at 1.6 vol%, 2.0 vol%, and 2.4 vol% decreases by 0.89 %, 6.39 %, and 10.13 %, respectively. Microscopic observations of FRGPC indicate that an increase in fiber dosage and length results in larger pores and uneven distribution of fibers. Notably, 12 mm PVA fibers exhibit significant aggregation, confirming the findings from mechanical property tests. This study, through an in-depth exploration of the mechanical properties of PVA fiber-reinforced fly ash-based geopolymer composites, provides crucial experimental data and a theoretical foundation for the development of sustainable construction materials.

Hydrothermal zeolitization: Towards a paradigm shift for producing stronger and more sustainable construction materials

The construction sector provides 14.8 million jobs in the European Union. However, it also accounts for 36% of greenhouse gas emissions and 35% of total waste. High-temperature ceramic manufacturing consumes substantial energy, yielding basic structural products. The alternatives presented, such as geopolymers, still do not replace traditional materials and are not as sustainable as believed. This innovative study combines hydrothermal zeolitization with kaolin-based ceramics fired at both conventional (900°C) and much lower temperatures (600°C), exploring varied conditions, including the use of microplastic wastes as pore-forming agents. Significant zeolite crystallization (15–74%) and mechanical strength increase (2–37-fold compared to untreated materials) is demonstrated in granular specimens, especially when adding microplastics. Geopolymerization appears as a secondary process during treatment. This innovative method offers energy-efficient lower temperatures, transforming fired specimens into zeolite-enriched, robust materials, adaptable to current technology. This study paves the way for further research, opening up a new field of study on hydrothermally manufactured Zeolitic Construction Materials.

Recycled Household Plastic and Oil Palm Filler Reinforced Epoxy Composite for Lightweight Construction Applications

Polypropylene is extensively used in aerospace, automotive and construction applications due to its versatile properties. This project aims to reduce plastic and oil palm waste and promote the development of strong, sustainable and eco-friendly construction materials. The objective of this project is to develop a sustainable yet high-performance construction material by incorporating polypropylene particles, oil palm empty fruit bunch (OPEFB) fibres and oil palm shell (OPS) particles into epoxy composites through the hand lay-up method. The composite specimens undergo ASTM D638 tensile test to determine the tensile properties. The addition of PP particles in varying weights shows decrease in tensile strength, likely due to poor dispersion and compatibility with the epoxy matrix. Incorporating 3 wt% OPEFB fibres with fibre length from 2mm to 4mm improves tensile strength by 2.32% and 23.36% respectively at higher PP particle loadings which are 15 wt% and 25 wt%. Adding 1 wt% and 3 wt% OPS particles improves the tensile strength by 2.96% and 4.68% respectively, in composites with 10 wt% PP particles and 3 wt% OPEFB fibres. The tensile performance may be improved by treating PP particles with compatibilizers such as silane or maleic anhydride grafted polypropylene.

Advancing Sustainable Construction Materials: Wood, Rubber, and Cenospheres Geopolymer Masonry Units Development

As the environmental impact of modern society continues to escalate, the construction industry actively pursues environmentally friendly materials to revolutionize its practices. Recycling, especially repurposing end-of-service materials and industrial wastes, emerges as a pivotal strategy offering a promising path towards sustainable construction. This study focuses on the innovative reuse of end-of-service wood, crumb rubber, and cenosphere with geopolymer binder to produce sustainable alternatives to masonry units. The study was conducted in two stages. In the first stage, cube samples were produced and tested to establish an optimal mix design. Results indicated that as the relative volume of waste increased, the compressive strength decreased. The compressive strength of the wood geopolymer composite decreased from 25 MPa to 4 MPa as the wood-to-binder ratio increased from 0.1 to 0.5. An increasing trend was observed for density with the increase of the rubber-to-wood ratio. The compressive strength also increased with the increase of the rubber-to-wood ratio for most of the investigated ranges. As fly ash is gradually replaced by cenospheres, a significant decrease in compressive strength was noted, about 70% and 80% for wood-to-binder (ratios of 0.2 and 0.3, respectively). In the second stage, three distinct types of masonry units were produced and tested based on the optimized mix design. The compressive strength results indicated promising performance, with wood-geopolymer masonry units exhibiting a strength of 8.39 MPa, wood-rubber-geopolymer masonry units achieving 8.32 MPa, and wood-cenosphere-geopolymer masonry units resulting in 7.33 MPa. While these values fell below the target 10 MPa, it is noteworthy that wood-geopolymer masonry units and wood-rubber-geopolymer masonry units met the minimum compressive strength requirements of some standards and demonstrated significantly better ductility compared to traditional masonry units. The results showcase significant promise in the viability and performance of these innovative masonry units.

Microscopic analyses and performance characteristics of granite powder blended cement

This research investigates the characteristics of Granite Powder (GrP) and its potential use as a partial replacement for cement in mortar production. The GrP samples were analyzed via microscopic techniques. The effects of GrP Blended Cement (GrPBC) were examined on the workability and mechanical characteristics by partially replacing Ordinary Portland Cement (OPC) with 0–40 wt% GrP in 4 wt% increments. Life cycled assessment in terms of Embodied Energy (EE) and Global Warming Potential (GWP) of GrPBC-based mortar were assessed based on cradle-to-gate boundaries and the sustainability and economic indexes were determined at 28 days compressive strength. The study proposed new models to predict the compressive strength of GrPBC with respect to Water to Binder (W/B) ratio. The presence of active minerals depicts GrP as pozzolanic materials. The optimum replacement level of GrP in the blended mix, based on the fresh and hardened properties of GrPBC, is 20 wt% to achieve 75% of the strength activity index. GWP and EE declined as the GrP in the mixtures rose. The best sustainable and economic prospects were attained at the 25 wt% GrP replacement level. The compressive strength and the W/B ratio are highly correlated. Thus, GrP has proven to be a sustainable construction material in the construction sector.

Enhancement of Flexural Strength in Fiber–Cement Composites through Modification of Sisal Fiber with Natural Rubber Latex and Expanded Perlite

This study presents a novel approach in enhancing the flexural strength of sisal fiber cement composites by employing a dual coating technique with natural rubber latex and expanded perlite to the sisal fibers. The effects of different fiber content (0.25, 0.5, 0.75, 1, 1.25, and 1.5 wt%) and fiber length (1, 2, and 3 cm) on the physical and mechanical properties of sisal fiber cement were also studied. The physical properties, including bulk density and water absorption, were evaluated via the Archimedes method. Flexural strength was measured using the 3-point bending method, and microstructure was observed using a scanning electron microscope (SEM) and an optical microscope (OM). As the fiber content and length increase, the bulk density of the sisal fiber cement decreases. However, composites utilizing coated fibers consistently exhibit a higher bulk density than those utilizing uncoated fibers, attributed to enhanced adhesion and reduced porosity. The water absorption of sisal fiber cement increases with fiber content, but it is mitigated by the natural rubber latex coating, which prevents fiber–water absorption, and by expanded perlite, which reduces voids in the matrix. Composites containing coated fibers consistently exhibit superior flexural strength compared to those with uncoated fibers. The highest flexural strength values of 5.58 MPa were observed in composites utilizing 3 cm of coated fiber with 0.25 wt% fiber content. Microstructure analysis reveals a well-bonded interface in coated fibers, emphasizing the positive impact of coating on mechanical performance. The incorporation of coated sisal fibers effectively improves adhesion, water resistance, and flexural strength, offering sustainable and durable construction materials. The achieved results can serve as the guidelines for the development of a high-performance bio-based construction materials with improved durability and reduced environmental impact.

The Thermo-Phase Change Reactivity of Textile and Cardboard Fibres in Varied Concrete Composites

The building and construction industry heavily relies on the use of concrete and cementitious composites due to their exceptional attributes, including strength and durability. However, the extensive use of these materials has led to significant environmental challenges, including resource depletion, carbon emissions, and waste accumulation. In response to these challenges, recent advancements in fibre cementitious composites have shown promise in mitigating these detrimental effects. The integration of waste materials to supplement manufactured fibres represents a promising development in reinforced concrete composite materials. Waste materials like textiles and cardboard are emerging as potential fibre supplements in cementitious composites. While these materials have primarily been investigated for their mechanical characteristics, understanding their thermal properties when applied in construction materials is equally crucial. Incorporating fibres within composite designs often requires matrix modification to reduce degradation and enhance fibre longevity. This study aims to investigate the thermo-phase change properties of both textile and cardboard fibres within varied concrete matrices. Additive materials offer a range of advantages and challenges when used in composite materials, with additional complexities arising when incorporating fibre materials. Understanding the thermal reactivity of these materials is crucial for optimizing their application in construction. This study demonstrates the potential of waste fibres used with gypsum, metakaolin, and silica fume as matrix modifiers in concrete. This research provides valuable insights for future studies to explore specific material combinations and investigate complex fire testing methods, ultimately contributing to the development of sustainable construction materials.

Review on Advancements in the Production of Artificial Aggregates from Industrial Byproducts: A Sustainable Solution for Infrastructure Development

This review paper explores the burgeoning interest in artificial aggregates as sustainable alternatives to traditional construction materials, driven by concerns over resource depletion and environmental degradation. It comprehensively examines recent advancements, challenges, and future prospects in this field. Beginning with an overview of the imperative for alternative aggregates in construction, the paper discusses various types of artificial aggregates sourced from industrial by-products, recycled materials, and innovative manufacturing processes. It delves into their mechanical, physical, and environmental properties, contrasting them with natural aggregates, and evaluates the impact of production techniques like sintering, foaming, and chemical activation on their performance. Environmental sustainability aspects, including carbon footprint reduction and waste management, are rigorously analyzed, underscoring the potential of artificial aggregates to mitigate ecological impacts associated with conventional extraction and processing methods. Addressing hurdles to widespread adoption, such as technological barriers and economic viability, the review proposes strategies for overcoming these challenges and outlines future research directions to optimize artificial aggregates' properties and applications. In conclusion, this review offers valuable insights into the state-of-the-art developments in artificial aggregate technology, highlighting their pivotal role in advancing sustainability and resilience within the construction sector. Key Word: Artificial aggregates, Sustainable construction materials, Environmental impact, Recycling, Waste utilization.

The Effectiveness of Styrofoam Mixtures in Lightweight Concrete Walls

This research explores the potential use of styrofoam concrete as a sustainable construction material with excellent acoustic properties. Considering variations in the thickness of styrofoam concrete, the study employs the NoiSee application on smartphones as an affordable and flexible noise measurement tool. The results investigate the potential of using styrofoam to reduce noise. The findings indicate that styrofoam, especially at a thickness of 4 cm, exhibits high effectiveness with a noise reduction of up to 60%. Additionally, the addition of styrofoam waste to brick mixtures can enhance the sound absorption coefficient at 800 Hz frequency. Styrofoam is effective in sound absorption below 1000 Hz, with thickness ranging from 1 cm to 3.5 cm improving sound absorption performance at various frequencies, while a thickness of 4 cm proves effective at 1000 Hz frequency. Overall, the combined results affirm the potential of styrofoam as a customizable soundproofing material for various acoustic applications. 

Influences of Recycled Polyethylene Terephthalate Microplastic on the Hygrothermal and Mechanical Performance of Plasterboard with Polymethylhydrosiloxane Content.

New composites produced with recycled waste are needed to manufacture more sustainable construction materials. This paper aimed to analyze the hygrothermal and mechanical performance of plasterboard with a polymethylhydrosiloxane (PMHS) content, incorporating recycled PET microplastic waste and varying factors such as PMHS dose, homogenization time, and drying temperature after setting. A cube-centered experimental design matrix was performed. The crystal morphology, porosity, fluidity, water absorption, flexural strength, and thermal conductivity of plasterboards were measured. The results showed that incorporating recycled PET microplastics does not produce a significant difference in the absorption and flexural strength of plasterboards. However, the addition of recycled PET reduced the thermal conductivity of plasterboards by around 10%.

Synergistic effect of nano silica and metakaolin on mechanical and microstructural properties of concrete: An approach of response surface methodology

Nano and micro materials are both effective individually in enhancing the mechanical and microstructural properties of concrete. The combination illustrates an iconic shift in material engineering to produce concrete with distinctive characteristics. In this work, the combined effect of Nano Silica (NS) and Metakaolin (MK) on the mechanical and microstructure properties were examined by conducting compressive strength, split tensile strength, and Field Emission Scanning Election Microscope (FE-SEM) with Energy-dispersive X-ray (EDX) analysis, X-ray Diffraction (XRD) spectroscopy, Fourier Transform Infra-Red (FTIR) spectroscopy, respectively. The concrete matrix was investigated by varying the concentration of NS and MK with different Water-Binder Ratio (WBR). Further, the Response Surface Methodology (RSM) technique was used to identify the complex interaction between NS (1–3 %) and MK (5–20 %) at different WBR (0.35, 0.40 and 0.45). The synergistic effect between NS and MK resulted in enhanced compressive and split tensile strengths of the concrete. The optimum mix proportion of the concrete was found to be 2 % NS and 12.5 % MK at a WBR of 0.4. The compressive strength enhancements for the optimum mix proportion were 35.75 %, 34.4 %, 33.1 %, and 32.5 %, while the split tensile strength enhancements were 26.56 %, 25.92 %, 20.95 %, and 17.8 %, respectively on the 7th, 28th, 56th, and 90th day. The RSM technique developed for all the mixes has been statistically validated to have less than 5 % of mean error. Moreover, the microstructural analysis revealed early hydration, formation of additional Calcium Silicate Hydrate (C-S-H) products, and presence of dense microstructure resulting in improved microstructural properties. The incorporation of NS and MK in the concrete changes the concrete’s configuration at the nano and micro levels, thus paving the way for the development of novel and sustainable construction materials.