Elastic Modulus Research Articles

Enhancing the Properties of Latex-Based Coatings with Carboxylated Cellulose Nanocrystals.

Latex-based nanocomposites containing carboxylated cellulose nanocrystals (cCNCs) were synthesized via in situ seeded semibatch emulsion polymerization. Inspired by nature's use of CNCs to enhance rigidity and mechanical strength in cellulosic materials, we explored similar principles to improve the properties of acrylate water-based coatings. The cCNCs, loaded at 0.3-1.0 wt %, were added 1 h after pre-emulsion feeding began, addressing sensitivity to ionic strength and enabling stable final latexes. Careful control of the polymerization process maintained consistent particle sizes across formulations, allowing for mechanical property comparisons. Films from these latexes were evaluated through rheological and water sensitivity tests. With 1.0 wt % cCNC, significant increases in viscosity, shear-thinning behavior, stiffness, and elastic modulus were observed. Additionally, cCNCs reduced water and moisture absorption without affecting the whitening resistance. These findings demonstrate the enhanced properties of in situ cCNC latex nanocomposites, broadening their potential for industrial applications.

Effect of Composition on Physical, Mechanical, and Thermal Properties of Oil Palm Empty Fruit Bunch Epoxy Resin Biocomposite

Oil palm empty fruit bunches (OPEFB) are wastes from oil palm processing. The objective of this work is to study the effect of composition on the physical, mechanical, and thermal properties of OPEFB epoxy resin biocomposite. Particles of OPEFB (100 mesh) were mixed with epoxy resin with the ratio of OPEFB to epoxy resin 60/40, 70/30, 80/20, and 90/10 (vol.%/vol.%). Biocomposites were produced by a press method at room temperature with 9 tons-load. The physical properties (density, porosity, water absorption, thickness swelling) of the biocomposite were evaluated. The mechanical properties (modulus of rupture and modulus of elasticity) of biocomposite were determined by using a universal testing machine. The thermal gravimetric analyzer (TGA) was used to examine the thermal properties of the biocomposite. The results show that the density of biocomposite is 1.18 g/cm3 for 60 vol.% of OPEFB composition. It decreases significantly as the OPEFB composition increases. For 60 vol.% of OPEFB, the porosity, water absorption, and thickness swelling of biocomposite (after soaking in water for 24 hours) are 11.9%, 10.1%, and 6.5%, respectively. All these values increase significantly with the increase of OPEFB composition. For 60 vol.% of OPEFB, the modulus of rupture (MOR) and modulus of elasticity (MOE) of biocomposite are 2.31 kgf/mm2 and 267 kgf/mm2, respectively. The values of MOR and MOE decrease significantly with the increase in OPEFB composition. TGA results show that degradation of biocomposites occurs significantly at 350°C for 60 vol.% OPEFB. The degradation temperature reduces as the composition of OPEFB increases. In general, the physical, mechanical, and thermal properties of biocomposites decrease with increasing OPEFB composition. This happens because the bond between the matrix and the particles decreases as the OPEFB composition increases. The maximum OPEFB composition that can be used for particleboard applications is 80 vol.%, which meet the ANSI 208.1-2009 requirements for application as grade M-2 particleboard.

Application of Lignin as Partial Binder Replacement in Magnesium Phosphate Bonded Paper Sludge Composite Products; Board Properties and Economic Analysis

AbstractThe study investigated the feasibility for partial phosphate binder replacement with lignin in phosphate bonded paper sludge composites. A central composite experimental design (CCD) was used to optimise the board manufacturing process, wherein the effect of process temperature, as well as lignin content were investigated with respect to board properties based on the ASTM D1037 standard. Moduli of rupture and elasticity of up to 7.2 MPa and 2.8 GPa respectively in the boards with lignin content of 36–43 wt% and formulation temperatures of 118–133 °C were observed. The phosphate binder input, which bears a huge cost in the process was reduced by up to 49% with lignin incorporation. The effect of pine veneer lamination on the strength properties of the composite boards was investigated. Pine veneer lamination improved mechanical properties, with the moduli of rupture and elasticity increasing from 7.2 to 22.1 MPa (67% increase) and 2.8 to 3.6 GPa (22% increase) respectively. The economic viability of the boards produced was also assessed and the results showed that the required selling price for the composite boards is competitive in the local market for inexpensive construction materials, sold at wholesale prices for between R 158/m2 and R 295/m2, depending on product finishing. Graphical Abstract

Physical and mechanical properties of the stem and branch wood of West African ebony (Diospyros mespiliformis)

This study examines the physical and mechanical properties of the sapwood and heartwood of the stem and branch wood of the West African ebony (Diospyros mespiliformis) to determine if the branch wood can be used for various products. Three mature Diospyros mespiliformis trees with stem diameters at breast height ranging from 50 to 65cm and branch diameters from 25 to 40 cm were purposively selected and felled. Wood samples were prepared to the exact sizes in accordance to the chosen standards, tested, and analysed. The results showed that wood density was insignificantly higher in the stem wood (551 kg/m³) than the branch wood (513 kg/m³). Radially, the heartwood had higher density than the sapwood for both stem wood and branch wood. The Modulus of Elasticity (MOE) was higher in the branch part (7066 MPa) than stem part (1903 MPa), and the sapwood recorded higher MOE for both stem wood and branch wood. Moreover, the Modulus of Rupture (MOR) had a similar result, with the stem part showing a higher average MOR (61 MPa) than the branch part (52 MPa), the sapwood had higher values as compared to its corresponding heartwood. The same trend was observed for the compression strength as well as Janka hardness. In general, it was shown that the branch wood could equally perform well when used as a supplement to the stem wood.

Residual reliability of a composite material subjected to buckling and post-buckling tests: the case of reinforced concrete

This article examines the residual reliability of composite materials, focusing on reinforced concrete subjected to buckling and post-buckling tests, a crucial topic in civil engineering. The main aim of the study is to assess how these loads affect mechanical properties, including compressive strength and elongation at break, while identifying associated failure mechanisms. A rigorous methodology was adopted, involving experimental tests on reinforced concrete samples, followed by microscopic analysis and comparison with literature data. The results reveal a significant decrease in compressive strength and modulus of elasticity with increasing loads and loading cycles. In addition, the study highlights a reduction in elongation at break, indicating a loss of ductility and stiffness of the material. Failure mechanisms observed include cracking and delamination, suggesting that the residual reliability of reinforced concrete is inferior to that of advanced composites. These findings underline the importance of appropriate design to ensure the durability of reinforced concrete structures, taking into account the impact of extreme loads and environmental conditions. This research contributes to a better understanding of the behavior of composite materials under critical conditions, providing recommendations for improving design and construction practices in civil engineering.

Numerically predicting deflections of mat-sand interaction model under gravity loadings

This research proposes a novel mat-sand interaction model to evaluate limiting values of sand elastic modulus and super-imposed gravity load for a specific mat thickness to control vertical deflection of mat by using BNBC 2020 prescribed allowable deflection limit. For this reason, the linear elastic analysis is performed by using finite element-based software ETABS v.18.1.1, whereas the impact of sand on the mat is transferred by springs. The difference in results between present and previous studies is obtained to be 1.76%, which may indicate good accuracy of verification of the proposed model with the field study data. The difference in mat vertical deflections between two consecutive sand elastic moduli is obtained to be 7.1%, and it is found to be 32.8% in the case of the mat thickness variations. So, the difference in the case of the sand elastic modulus is reduced by 78.4% compared to the mat thickness. The limiting value of imposed gravity load is found to be 60 kPa for 150 mm mat thickness with a range of sand elastic modulus of (5–25) MPa. Similarly, it is obtained to be 120 kPa in the case of the 200 mm mat thickness for 5 MPa elastic modulus of sand. These findings may help engineers to select suitable mat thickness with corresponding sand elastic modulus and super-structure gravity load.

Modeling and numerical analysis of concrete specimen under dynamic and thermal loading taking into account non-linearity

In this study, we propose a model describing the mechanical behavior of basalt aggregate concrete under high temperatures. Basalt aggregate concrete is formulated. The bulk density, residual mechanical (compressive strength, tensile strength and elastic modulus) and microscopic properties of basalt aggregate concrete specimens are analyzed. The damage basalt aggregate concrete, the geometry and nonlinear behavior of the material is investigated. Based on Newton’s second law, the investigation is conducted on the simultaneous effects of mechanical loading and thermal treatment. The finite difference method is used for the numerical solution of the problem to determine the peak stress and strain of normal basalt aggregate concrete as a function of temperatures and time. It follows from the results obtained that, after [3–5 min] the critical temperature at which material damage, for both stress and strain, is observed to be 350 °C at the center, corresponding to a 30% reduction in peak stress on the value initially obtained experimentally; And 300 °C at the free and fixed end of basalt aggregate concrete specimen respectively, corresponding to a 38 and 30% reduction in stress in the z-axis direction. Beyond these temperatures, it is observed that the amplitude of the deformations continues to increase whatever the position announcing an imminent collapse of the material, probably due to the loss of stiffness of the cement paste which significantly reduces the mechanical performance of the normal basalt aggregate concrete observed experimentally.

Bioinspired Design of Isotropic Lattices with Tunable and Controllable Anisotropy

This study presents novel nested isotropic lattices, drawing inspiration from bio‐architectures found in cortical bone osteons, golden spirals, and fractals. These lattices provide tunable anisotropy by integrating architectural elements like “nesting orders (NOs)” and corresponding “nesting orientations (NORs),” along with repetitive self‐similar X‐cross struts and three fourfold axes of symmetry, resulting in a wide spectrum of novel lattice designs. Nine mon‐onest and 20 multinest lattices, along with 252 parametric variations, are realized. Employing finite element‐based numerical homogenization, elastic stiffness tensors are estimated to evaluate the anisotropic measure—Zener ratio and elastic modulus. The mono‐nest lattices generated considering higher NOs and respective NORs exhibit a transition from shear dominant to tensile‐compression dominant (TCD) anisotropic behavior and their strut size variations show a strong influence on performances. In contrast, multinest lattices exhibit isotropic and neo‐isotropic characteristics, with strut size mismatch exerting more influence on the Zener ratio. Increasing NOs and NORs result in isotropic or TCD behavior for most multinest lattices, with strut size mismatch leading to many isotropic lattices. These bioinspired nested lattices, coupled with advancements in additive manufacturing, hold potential for diverse applications.

Evaluation of stress distribution in coronal base and restorative materials: A narrative review of finite element analysis studies

Background: Analyzing the stresses created by functional and parafunctional forces on teeth, bones, soft tissues, and intraoral dental materials is crucial for enhancing the success and development of restorations. Purpose: The purpose of this review is to evaluate studies that examine stress distribution in coronal base and restorative materials using the method of finite element analysis. Review: The three-dimensional finite element analysis method is extensively utilized to study biomechanical behavior and assess stress distribution within dental materials. Numerous studies from 2010 to 2024 have investigated the stress caused by polymerization shrinkage and the distribution of stress in various base and restorative materials. Conclusion: This review emphasizes findings related to stress distribution in coronal base and restorative materials, stressing the importance of considering the elastic modulus and thickness of base materials, and highlighting the need for additional research in this field.

Elastic properties of rock salt ScN thin films investigated by laser ultrasound

Elastic moduli of scandium nitride (ScN) films are determined using a laser-based experimental method working with surface acoustic waves (SAWs). ScN, a semiconductor material with promising potential for various applications, crystallizes in the cubic rock salt (rs) structure. We investigate two samples of high-crystallinity ScN(111) films with thicknesses ∼200 and ∼300 nm, grown on Si(111) substrates by pulsed DC-magnetron co-sputtering and a sample with a fiber-textured ScN film (∼800 nm) on Si(001). From the shape evolution of laser-generated acoustic pulses, SAW dispersion curves were obtained in a frequency range of 50–500 MHz. In order to take advantage of the anisotropy of the film and substrate materials, measurements were performed for 10–15 SAW wavevector directions, which could be defined with a precision of 0.2°. Using perturbation theory with respect to the ratio of film thickness and SAW wavelength, two combinations of the three independent elastic constants of the high-crystallinity rs ScN films could be extracted from the measurement data. The surface roughness of the ScN films is accounted for with a simple model. Complete sets of the three elastic moduli were inferred in two different ways: (i) SAW dispersion data for the third sample were included in the extraction procedure; and (ii) the bulk modulus is set equal to a theoretical literature value. The extracted values for the three elastic constants are at variance with published theoretical results for single-crystal ScN. Possible reasons for these discrepancies are discussed.

Experimental Determination of Circumferential Mechanical Properties of GFRP Pipes Using the Split-Disk Method: Evaluating the Impact of Aggressive Environments

This study investigates the mechanical properties of Glass Fiber-Reinforced Plastic (GFRP) pipes in the circumferential direction using the split-disk method, with a focus on understanding the influence of aggressive environmental conditions. The split-disk method was used to determine the key mechanical properties, including the hoop tensile strength and modulus, and also the Poisson’s ratio, which are critical for the performance of GFRP pipes under internal pressure. The experiment was conducted under controlled laboratory conditions, and the results were analyzed to assess the effects of exposure to aggressive environments (saltwater and alkaline solutions at 20 °C and 50 °C). The correlations between the UTS, elastic modulus, and Poisson’s ratio highlight how GFRP pipes degrade under environmental exposure. As the UTS decreases, so do the stiffness and lateral deformability, with the most significant reductions occurring in chemically aggressive environments at high temperatures. Exposure to an alkaline solution weakens the GFRP pipes, with the strength dropping more sharply at higher temperatures, with the UTS decreasing by 21%. Saltwater exposure reduces the elastic modulus, especially at higher temperatures, with a 14% decrease, accelerating material degradation and reducing deformation resistance. An alkaline solution further lowers the modulus, with a 21% decrease at 50 °C, showing the lowest stiffness. Air exposure, in contrast, has a less severe effect, with the pipes retaining much of their mechanical integrity. These findings collectively suggest that environmental degradation affects the overall mechanical behavior of GFRP pipes, providing valuable insights for the design and maintenance of GFRP piping systems, particularly in industries where exposure to aggressive environments is common. This study underscores the importance of considering environmental factors in the material selection and design processes to ensure the long-term reliability of GRP pipes.

Relationship Between the Carbonation Depth and Microstructure of Concrete Under Freeze–Thaw Conditions

Concrete structures in cold regions are affected by freeze–thaw cycles (FTCs) and carbonation, which lead to the premature failure of concrete structures. The carbonation depth, relative dynamic elastic modulus (RDEM), compressive strength, porosity, and pore size distribution of concrete under FTC conditions were tested through an accelerated carbonation experiment to study the carbonation performance evolution. The freeze–thaw effect mechanism on concrete carbonation was further analyzed via the obtained relationship between carbonation depth and pore structure. The results showed that the FTC, as a powerful source of concrete damage, accelerates the carbonation reaction. Carbonization products fill some microcracks caused by the freeze–thaw process, improve the compressive strength and dynamic elastic modulus, and alleviate the damage to concrete caused by the FTC. After carbonization under freeze–thaw damage conditions, the content of macropores with d > 1000 nm decreases, while the content of transition pores with d ≤ 10 nm increases, which is the direct reason for the decrease in porosity and the improvement in strength. Therefore, the carbonation durability of concrete under freeze–thaw conditions can be improved by controlling the content of macropores with d > 1000 nm and increasing the content of transition pores with a pore size of 10 nm ≤ d < 100 nm. In addition, the relationship between carbonation depth and pore structure under freeze–thaw conditions was established, and the research results can provide a reference for the study of the carbonation performance of concrete under freeze–thaw conditions.

Impaction bone grafting for acetabular bone defects replacement in revision hip arthroplasty: biomechanical aspects

Background. The leading role in long-term survival of the prosthesis installed using impaction bone grafting is given to the mechanical properties of the graft. The aim of the study is to explore the mechanical properties of osteoplastic material and determine the potential impact of cyclic loads on dynamic changes in the position of the acetabular component after revision hip arthroplasty using impaction bone grafting. Methods. We conducted an experiment evaluating the impact of cyclic loads on the mechanical properties of osteoplastic material. At the first stage, a single-cycle tension-compression testing was carried out. Cyclic tests were carried out at the second stage of the experiment. Taking into account the presence of blood in the wound, we provided for a model with an aqueous solution of 45% glycerin. Clinical interpretation of biomechanics was carried out basing on the dynamic radiography data of two patients who underwent revision hip arthroplasty with the use of impaction bone grafting (IBG). The changes in the position of the rotation center and acetabular component were assessed. Results. During a single-cycle loading, we observed stress-strain dependences and instantaneous elastic moduli for each specimen. During cyclic tests, we obtained the increase of the instantaneous elastic modulus by 2.6 times for a “dry” specimen and from 3.9 to 4.7 times for the ones with liquid. X-rays of both patients showed the shift of the center rotation cranially and laterally: 2.4 and 1.5 mm in the first case and 14.9 and 9.5 mm in the second one, respectively. In the first case the change in the inclination was 18.7º, in the second case — 19.8º. The Hip Harris Score (HHS) was 97 points for the first patient, 53 points — for the second one. Conclusions. The material used for IBG is subject to deformation both in the intraoperative and postoperative period. Compression tests have suggested that the deformation of morselized impacted bone graft gradually tends to reach a plateau in the postoperative period, and with the completion of the deformation, migration of the acetabular component stops. The change in the position of the rotation center and acetabular component in the absence of a radiolucent line is not an absolute sign of loosening.

Pressure relief for drilling (trenching) and support technology in deep soft rock tunnels

Controlling surrounding rock stability in deep soft rock tunnels solely by increasing the support strength is challenging. The key areas where the surrounding rock of a roadway is prone to “instability” should be treated with comprehensive measures, such as drilling to relieve pressure, grouting of the surrounding rock, floor trenching technology, and secondary support, to achieve overall stability of the roadway surrounding rock. In this paper, based on a typical straight wall semi-circular arch roadway project in the Huaibei mining area of Anhui Province, mechanical parameters, such as cohesion, internal friction angle, Poisson’s ratio, and elastic modulus of the surrounding rock, were measured. Displacement stress distribution in surrounding roadway rock were simulated and analyzed using FLAC 3D, and the key parts of the surrounding rock prone to instability under the original roadway support conditions were determined. A suitable arrangement and parameters of the borehole pressure relief in the side roadway, floor grouting, floor trenching, and floor bolt secondary support were selected. Engineering measurements indicated that the engineering techniques were successful. It provided a significant reference for the comprehensive management and treatment of the surrounding rock stability in deep soft rock roadway on a global scale.

Computational Search for Compounds with the Highest Melting Temperature in the Ternary HfC‐Based Ceramics

The melting temperature (Tm) determines the service temperature of ultrahigh‐temperature ceramics (UHTCs), so it is of great significance to search for compound with the highest Tm in UHTCs. In present work, the formula to calculate the Tm of UHTCs with the rock salt structure is modified first: Tm = f(c)EVm/(100kB), f(c) = 0.6412*c + 0.9947, which considers the influence of vacancy concentration (c) on the Tm. The calculated Tms are in good agreement with the experimental values of UHTCs, and the calculation accuracy exceeds 91%. The Tm could be obtained by only calculating the elastic modulus and volume per atom. Using this formula, the Tms of ternary HfC‐based UHTCs with the rock salt structure are predicted, and a new compound with the highest melting temperature, HfTa2C3, is found. Finally, the empirical relationship between the Tm and shear modulus or Vickers hardness of UHTCs with the rock salt structure is also investigated.

Aspergillus nidulans cell wall integrity kinase, MpkA, impacts cellular phenotypes that alter mycelial-material mechanical properties

Mycelial materials are an emerging, natural material made from filamentous fungi that have the potential to replace unsustainable materials used in numerous commercial applications (e.g., packaging, textiles, construction). Efforts to change the mechanical properties of mycelial-materials have typically involved altering growth medium, processing approaches, or fungal species. Although these efforts have shown varying levels of success, all approaches have shown there is a strong correlation between phenotype (of both fungal mycelia and mycelial material’s assembly) and resultant mechanical properties. We hypothesize that genetic means can be used to generate specific fungal phenotypes, leading to mycelial materials with specific mechanical properties. To begin to test this hypothesis, we used a mutant of the model filamentous fungus, Aspergillus nidulans, with a deletion in the gene encoding the last kinase in the cell wall integrity (CWI) signaling pathway, mpkA. We generated one set of mycelial materials from the ΔmpkA deletion mutant (A1404), and another from its isogenic parent (A1405; control). When subjected to tensile testing, and compared to material generated from the control, ΔmpkA material has similar elastic modulus, but significantly increased ultimate tensile strength, and strain at failure. When subjected to a fragmentation assay (i.e., resistance to shear-stress), the ΔmpkA material also had higher relative mechanical strength. To determine possible causes for this behavior, we carried out a comprehensive set of phenotype assessments focused on: three-dimensional structure, hyphal morphology, hyphal growth behaviors, and conidial development. We found, compared to the control, material generated from the ΔmpkA mutant manifests significantly less development, a modified cell wall composition, larger diameter hyphae, more total biomass, higher water capacity and more densely packed material, which all appear to impact the altered mechanical properties.Graphical

In-Situ Nanoindentation Surface Topography of Lead-Free Piezoelectric Thin Films

Surface roughness significantly affects the performance of microelectromechanical systems (MEMS) and piezoelectric films. This study investigates the impact of surface roughness on the mechanical properties of thin piezoelectric films using nanoindentation and scanning probe microscopy (SPM). Four piezoelectric films with different thicknesses (220, 350, and 450 nm) and substrate configurations (LNO/SiO2/Si or LNO/Si) were analyzed. A discriminant analysis revealed that the fractal dimension is more effective than the arithmetic mean height (Sa) for distinguishing surfaces, with only 2% misclassification versus 25% for Sa. A multiscale analysis identified the Smr2 parameter with low-pass filtering at 140 nm as highly effective for surface discrimination, achieving only 0.1% misclassification. The analysis of the roughness parameter Sa at various scales showed that band-pass filtering at 500 nm yielded a 0.7% misclassification rate, indicating its relevance for fractal roughness characterization. Most relevant roughness parameters for mechanical property correlation were found: Smr2 with low-pass filtering at 500 nm correlated best with hardness (R2 = 0.82), and Vvc with low-pass filtering at 2 nm correlated best with reduced elastic modulus (R2 = 0.84). These results demonstrate that surface roughness features like valley volume and voids significantly impact the apparent mechanical properties of piezoelectric films.

Effect of calcium lignosulphonate addition on some physical and mechanical properties of high-density fiberboard

Calcium lignosulfonate (CLS) (C20H24CaO10S2) is widely used in various industries today, including wood, construction, food, agriculture, and textiles. It has been noted that there are currently few studies on the addition of CLS chemicals to various fiberboards. This study was designed to explore the outcomes of the interaction between CLS and the boards, with the aim of expanding the potential applications of this chemical. In this study, we incorporated CLS at varying percentages (6%, 8%, and 10%) as an adhesive additive in high-density fiberboard (HDF) produced using urea-formaldehyde (UF) resin in a laboratory setting. We assessed its impact on several physical properties [thickness swelling (TS), density, and water absorption (WA)] and mechanical properties [modulus of rupture (MOR), internal bond strength (IB), modulus of elasticity (MOE), and surface soundness (SS)]. A control group was established using prepared boards, allowing for a comparison of results between boards made with and without CLS additives. According to the results of a multivariate analysis of variance, the CLS percentage showed no significant effect on density, MOE, and SS. However, it significantly influenced TS, WA, IB, and MOR, resulting in reductions of 4-12% for SS, 6-12% for MOR, and 2-22% for IB, while increasing TS by 20-130%, WA by 25-84%, and MOE by 1-3%. It was observed that the use of CLS in the study led to differing results in the tests conducted on the produced HDF materials.

Enhancing the Performance of Layered Wood Composites Through the Non-Food Application of Dietary Fiber in Their Bonding Matrix

Rye flour is a commonly used filler in plywood production, made from finely ground rye grains. It enhances glue viscosity, ensuring even distribution and better adhesion, which improves the plywood’s mechanical properties, dimensional stability, and resistance to warping. Additionally, rye flour increases the plywood’s strength and durability, making it more resistant to mechanical damage and external factors. Its affordability and availability further support its widespread use in plywood production. However, the growing availability of new raw materials has sparked interest in alternative fillers, especially considering food waste challenges caused by low demand or poor household management. This study explores the potential of spirulina, bamboo flour, lupine flour, and coconut flour as alternative fillers to rye flour, being part of the food chain, in three-layer plywood production. Plywood panels were manufactured using birch and pine veneers, urea-formaldehyde resin, and varying filler contents (10, 15, and 20 parts by weight/pbw). Key mechanical properties were evaluated, including modulus of elasticity (MOE), modulus of rupture (MOR), shear strength, density profile, and filler water absorption. The highest MOE for hardwood plywood was observed with coconut flour (20 pbw, 17,228 N mm−2). Conversely, the lowest MOE values were recorded for coniferous plywood with spirulina (8440 N mm−2). For MOR, the best performance in softwood was achieved using lupine flour (10 pbw, 113 N mm−2), while coconut flour yielded the highest MOR in hardwood plywood (20 pbw, 177 N mm−2). Spirulina exhibited the lowest MOR (72 N mm−2, 15 pbw). Shear strength peaked with lupine and coconut flour. The filler composition determines adhesive properties and bond performance through water absorption, structural interactions, and filler content optimization. These findings emphasize the potential for fine-tuning alternative fillers to achieve desired mechanical performance, ensuring sustainable and efficient plywood production. These also demonstrate the potential of certain alternative fillers, particularly coconut and lupine flours, excluded from the food value chain, in improving specific properties of plywood.

SHEAR STRENGTH PARAMETERS AND DEFORMABILITY PROPERTIES OF SILICATE-BASED RESIN ADDED SAND-TYPE SOIL SPECIMENS

In this study, the shear strength, uniaxial compressive strength (UCS) values and deformability properties of silicate-based polymer resin added silty sand type soil specimens were examined through a series of experimental studies. Although the UCS and shear strength values increased, minor decreases in the internal friction angle values were measured as the resin ratio increased. It was determined that the main reason of improvement in the strength values due to the increase in resin content is the increase in cohesion values. It was found that the UCS values calculated according to the cohesion and internal friction angle parameters of the Mohr&Coulomb failure criterion (UCSc) were 2.6-3.0 times lower than the values obtained from the direct UCS experiment. According to this finding, it was concluded that the Mohr&Coulomb failure criterion is not properly usable to represent the mechanical behaviors of resin added sands. As another outcome, the ratio between UCS/UCSc slightly decreased with an increase in the resin amount. In other words, it has been determined that the Mohr&Coulomb failure criterion gives a bit more inaccurate results for the specimens with low binder contents. With the increase in the resin content ratio, significant increases were obtained in both elastic modulus and ductility properties of the samples. It has been evaluated that the silicate-based polymer resin binder is advantageous to provide significant increases in the toughness and energy absorption capacity of soils.