Cup Plant (Silphium perfoliatum L.) Biomass as Substitute for Expanded Polystyrene in Bonded Leveling Compounds

Biomass for non-food applications is considered as a substitute for petro-based materials such as expanded polystyrene (EPS). This research analyzes physical properties of an EPS containing commercial bonded leveling compound (BLC) which was substituted with cup plant (Silphium perfoliatum L.) biomass. Cup plant is a high-yielding biomass plant with several ecological benefits that is yet mainly used for biogas production. Furthermore, the high amount of parenchyma in senescent biomass with its EPS-like structure could be a possible substitute for petrochemical foams in lightweight aggregates. The natural variation in parenchyma content of several European cup plant accessions is promising, regarding the development of cultivars with suitable biomass properties for the proposed material use. Two binders with different proportions of cup plant and EPS were used to produce samples of BLC for thermal conductivity and compression strength tests. The compression strength of 0.92 N mm−2 and a thermal conductivity of 84 mW m−1 K−1 were analyzed and comparable to the commercial BLC. The thermal conductivity within the tested borders appears nearly independent of the biomass content. With increasing cup plant content, the shape characteristics of the lightweight aggregate mix changes towards more elongated aggregates. The mechanical strength and thermal conductivity are highly sensitive to the water demand of the biomass. Direct partial substitution of EPS by cup plant appears feasible and could be a part of the decarbonization of the construction sector.

Physical, Thermal and Microstructural Characterization of Earth Mortars Stabilized with Incorporating Air Additive

In recent years, the search for non-conventional materials has intensified, aiming to reduce environmental impacts in the civil construction sector as a strategy for more sustainable development. Among these materials, earth mortars are a promising option, as they have technological, economic, and environmental advantages. Due to the absence of literary data on the use of air-incorporating additives (AEA) in earth mortars, the objective of this article is to verify the influence of the incorporation of AEA (0,10, 20, and 40% of the total volume of the mixture) in the mechanical properties (compression strength at 28 days), physical (total water absorption by immersion), thermal, and microstructural (scanning electron microscopy) of the referred mortars. The study was carried out in a stabilized earth mortar, with a 1:3 mass mix proportion (binder: aggregate). The raw materials used were constituted by binders (cement, hydrated lime, fly ash, metakaolinite), aggregates (sand, a coarse fraction of the soil), additives (AEA, calcium chloride, superplasticizer), and water. The water-binder material ratio (a / bm) was fixed at 0.65, and the consumption of binder and aggregate was 461.71 and 1385.12 kg, respectively, per m3 of the mixture. The tests demonstrated that the incorporation of the additive influenced the behavior under compression (strength and stiffness reduction), thermal performance (conductivity reduction), and physical behavior (absorption and voids index´s increases) compared to the mixture without AEA. From the analysis of the results, it was found that the incorporation of air in the mortars led to an increase in porosity, directly influencing the thermal insulation capacity, measured by thermal conductivity. Microstructure changes were observed through SEM images, corroborating the influence of the AEA. Under compression loads, the stiffness reduction decreases the risk of eventual cracking, however, the reduction in strength should be controlled to meet normative limits.

High-pressure compacted recycled polymeric composite waste materials for marine applications

Abstract Options for recycling fiber composite polymer (FCP) materials are scarce, as these materials cannot be normally recycled and are toxic when improperly disposed. Additionally, reducing water usage is an increasing concern, as the concrete industry currently uses 10% of the world’s industrial water. Therefore, building upon our previous work, this research explores the use of polymer hybrid carbon and glass composite waste products as reinforcements in high-pressure compacted cement. Our material used nearly 70% less water during manufacturing and exhibited improved durability and salt corrosion resistance. Compression strength tests were performed on high-pressure compacted materials containing 6.0 wt% recycled admixtures before and after saltwater aging, and the results showed that the material retained 90% of its original compression strength after aging, as it contained fewer pores and cavities. Our experimental work was supplemented by molecular dynamics. Simulations, which indicated that the synergetic effects of compaction and FCP admixture addition slowed the diffusion of corrosive salt ions by an average of 84%. Thus, our high-pressure compacted cement material may be suitable for extended use in marine environments, while also reducing the amount of commercial fiber composite polymer waste material that is sent to the landfill. Article Highlights Fiber composite waste was successfully recycled into denser, high-pressure compacted ordinary Portland cement materials. High-pressure compacted cement samples containing 6% recycled admixtures retained 90% of their compression strength after salt aging. The high-pressure compaction method utilized 70% less water during specimen fabrication.

Compression strength-focused properties of wood composites induced by structure

Compression strength-focused properties of wood composites induced by structure. The aim of the following study was to examine the contractual compression strength and modulus of elasticity when compressing (MOEC) of three different wood composites with various structure types: softwood (coniferous) plywood, OSB and laminated particleboard 24 mm thick. The biggest MOEC value was performed by the particleboard laminated 24 mm MOEC equalling 70.00 N/mm2. The second was found by the OSB panels, equalling 63.03 N/mm2. Last, but with MOEC value close to OSB, was softwood plywood with MOEC of 62.44 N/mm2. The lowest compression strength was observed by OSB samples, with a value of 2.75 N/mm2. The second lowest value has been performed by coniferous plywood (2.80 N/mm2). The highest compression strength occurred by the particleboard laminated 24 mm, equalling 3.31 N/mm2. Density shares and density profiles of the samples were also analysed, all of the examined composites performed U-shaped density profile The results of the study showed that there is no significant correlation between density and obtained parameters under compression. Observation of density share let the Authors conclude conversely than the results showed. It is supposed that the key factor affecting the compression performance of samples was the adhesive area and solid glue content within the composites. It is assumed that the bigger total contact surface of wood particles coated with adhesive resin, so the sum of the effective (gluing particles) surfaces of the adhesive joint is the better mechanical properties can be performed. This is why the laminated particleboard gave the best mechanical properties, while the worst were observed by the softwood plywood.

Experimental Studies on Mechanical Properties of Carbon Nanotube Reinforced Aluminum 7075 Composite Material

In the present work multiwalled carbon nanotubes were added as reinforcement to aluminum 7075 matrix at 0.5%, 0.75% and 1.25% by weight proportion through stir casting technique. The mechanical properties of the produced composite were studied. The composite has considerably good tensile and wear resistance properties and hence finds its best suited application in aircraft frame and wings structures. Microstructure analysis through SEM showed a uniform distribution of the reinforcement material in the matrix. XRD graphs were taken at selected points during microscopic studies to determine the chemical composition of the matrix alloy, the reinforcement and the composite. The experimental results showed that 1.25% reinforcement in the composite material exhibited a tensile strength of 560 N/mm2 and a compression strength of 649.6 N/mm2 as the highest among the compositions. Thus, the reinforcement addition at 1.25% improved the tensile and compression strength of the composite material.

Compression strength-focused properties of wood composites induced by density

Compression strength-focused properties of wood composites induced by density. The aim of this study was to analyse the contractual compression strength and modulus of elasticity under compression of ten commercially available wood composites of various thickness, density, structure and surface finish. Density and density profiles have also been performed. The tests showed that there is no significant dependence of the compression strength and MOEC on the density of composites.

Cellular Glass Manufactured by Microwave Irradiation of Residual Glass, Eggshell and Borax

The paper presents an improved method of manufacturing cellular glass using residual glass (91 %), sodium borate (5 %), eggshell waste (4 %) and added water (9 %). Compared to methods using eggshell as an expanding agent producing cellular glass with low compression strength, the technique adopted by the authors is original by the addition of sodium borate, which contributes to increasing the compression strength and the use of the unconventional electromagnetic wave heating method, which ensures very economical specific energy consumption. The optimal variant of cellular glass had the following characteristics: density of 0.40 g/cm3, porosity of 81 %, heat conductivity of 0.086 W/m·K, compression strength of 4.3 MPa and the cell dimension between 0.3-0.9 mm. The specific energy consumption of the process was 0.80 kWh/kg. The product has adequate features for using as a heat insulation material under conditions of quite high mechanical loading.

Green strength properties of waterjet abrasive waste as potential composition in green mould by Taguchi and ANOVA approach

The sand casting process still continues today due to the cost-effectiveness of materials and processes. There is a wide variety of castings related to composition and size, but silica sand is widely available from coastal line mining and has a negative impact on the environment. Moreover, waste from waterjet cutting of non-ferrous and ferrous metals is practically unhazardous and may potentially be used in sand casting mould. The aim of this paper is to optimize the proportion of coal dust, water and bentonite added to the silica sand mixture and the waterjet cutting abrasive waste as a new way of handling waste with the potential to be used in sand casting manufacturing. The method used was L9 orthogonal array optimization and the composition was qualitatively measured using a green compression strength test and a green shear strength test. Factors were evaluated using the analysis of variance (ANOVA) to find the the critical factors while confirmation test was conducted for the optimal material proportion. The study concluded that the ideal ratio for silica sand mixture with waterjet abrasive waste is bentonite-12%, coal dust-5%, and water-7% for green compression strength while bentonite-12%, coal dust-6%, water-7% for green shear strength. With proper selection, the incorporation of waterjet abrasive waste into the green sand mixture is promising to potentially be used in green sand mould casting without undermine the quality of mould.

Compression Behaviour of Bio-Inspired Honeycomb Reinforced Starfish Shape Structures Using 3D Printing Technology

The bio-inspired structure (e.g., honeycomb) has been studied for its ability to absorb energy and its high strength. The cell size and wall thickness are the main elements that alter the structural ability to withstand load and pressure. Moreover, adding a secondary structure can increase the compressive strength and energy absorption (EA) capability. In this study, the bio-inspired structures are fabricated by fused deposition modelling (FDM) technology using polylactic acid (PLA) material. Samples are printed in the shape of a honeycomb structure, and a starfish shape is used as its reinforcement. Hence, this study focuses on the compression strength and EA of different cell sizes of 20 and 30 mm with different wall thicknesses ranging from 1.5 to 2.5 mm. Subsequently, the deformation and failure of the structures are determined under the compression loading. It is found that the smaller cell size with smaller wall thickness offered a crush efficiency of 69% as compared to their larger cell size with thicker wall thickness counterparts. It is observed that for a 20 mm cell size, the EA and maximum peak load increase, respectively, when the wall thickness increases. It can be concluded that the compression strength and EA capability increase gradually as the cell size and wall thickness increase.

Prediction of Uniaxial Compression Strength of Limestone Based on the Point Load Strength and SVM Model

Uniaxial compression strength (UCS) is a fundamental parameter to carry out geotechnical engineering design and construction. It is simple and efficient to predict UCS using point load strength (PLS) at engineering sites. However, the high dispersion of rock strength limits the accuracy of traditional fitting prediction methods. In order to improve the UCS prediction accuracy, 30 sets of regular cylindrical specimen tests between PLS and UCS are conducted on limestone mines. The correlation relationship between PLS and UCS is found by using four basic fitting functions. Then, a prediction model is established by using SVM algorithm. Multiple training test data are used to achieve high-precision prediction of UCS and the results show it is less different from the actual values. Especially, the R2 coefficient reached 0.98. The SVM model prediction performance is significantly better than the traditional fitting function. The constructed SVM model in this study can accurately predict the UCS using the PLS obtained in the field, which has a great significance to the rock stability judgment in the actual construction environment.