Modulus Of Rupture Values Research Articles

Analysis of Mechanical Properties of Timber Materials

This study aims to conduct the value of modulus of rupture (MOR) and modulus of elasticity (MOE) where the flexural strength is one of the highest mechanical properties compared with other mechanical properties. The method used is a flexural strength test using a three-point loading test, whereas for specific gravity and moisture content using the drill method. The materials used in this study are Bangkirai, Teak, Camphor, Sukun, and Coconut wood. The results of this study indicate that the moisture content is directly proportional to the value of MOR and MOE, except for the MOE of Coconut wood. The specific gravity is linear with MOE, except for MOR and MOE (coconut and teak wood).

Assessment of mechanical properties of cement stabilized soils

Recently, the cement stabilized soil is widely used in pavement applications due to its high potential saving in cost and time. An extensive laboratory tests were conducted to study the mechanical properties of cement stabilized materials in this research. Three studied soils included sand, laterite and clay. The X-ray diffraction (XRD) and X-ray Fluorescence (XRF) were carried out on the three subgrade samples to determine the quantities of morphological formation and chemical compound. The effect of cement content on the strength of the cement-stabilized soil samples was examined via the unconfined compression strength (qu) test, the soaked California bearing ratio (CBR) test, the third-point loading test and the plate loading test. The results showed that the 28-day qu, the soaked CBR, the modulus of rupture (MR) and the modulus of subgrade reaction (K) of the 3 stabilized subgrade materials increased with an increase in cement content. The relationships of K, soaked CBR and MR versus qu were developed. With the known qu value, the K, soaked CBR and MR values can be simply approximated. Finally, the K values by the proposed method were validated by comparing with the FEM results. Therefore, these developed relationships are useful for researchers, engineers and practitioners in pavement design.

Strength and Dimensional Stability of Cement-bonded Boards Manufactured from Mixture of Ceiba pentandra and Gmelina arborea Sawdust

Cement bonded boards of 6 mm in thickness were produced from the mixture of Ceiba pentandra and Gmelina arborea sawdust. The influence of weight to weight proportion of C. pentandra and G. arborea blended at levels of 100:0, 75:25, 50:50, 25:75 and 0:100 in mass and mixing ratios of cement to wood 2:1 and 3:1 on Modulus of Rupture (MOR), Modulus of Elasticity (MOE) Water Absorption (WA) and Thickness Swelling (TS) properties of the experimental boards were examined for 24 h and 48 h immersion in cold water. The mean values for MOE and MOR were from 2479.50 to 5294.30 N/mm2 and 0.82 N/mm2 to 3.02 N/mm2 respectively, while the mean values for TS and WA after 24 h in cold water were from 0.53% to 7.35% and 14.8% to 52% respectively, whereas after 48 h in cold water immersion the mean values for TS and WA were from 2.37% to 10.48% and 16.5% to 69.5% respectively. It was observed that, increase in G. arborea (75%) to C. pentandra (25%) and mixing ratio 3:1 (cement/wood) was responsible for increase in MOR and MOE and decrease in TS and WA. The result shows that cement-bonded boards can be manufactured from Ceiba pentandra sawdust when mixed at certain blending proportion and ratio.

Non-biocide antifungal and anti-termite wood preservation treatments based on combinations of thermal modification with different chemical additives

The synergic effect between a mild chemical and thermal modification of beech wood (Fagus sylvatica) has been studied. A low concentration of additives based on vinylic-polyglycerol, vinylic-glycerol, and maleic anhydride was impregnated into beech wood, followed by curing under different temperature conditions at 103, 150, 200, and 220 °C. The modified wood was then analyzed for its leaching resistance, dimensional stability, wettability, modulus of elasticity (MOE) and modulus of rupture (MOR) in bending, decay resistance against Trametes versicolor, and termite resistance against Reticulitermes flavipes. Results have disclosed a synergic effect of thermo-chemical wood modification under 200 and 220 °C curing conditions. At these curing temperatures, thermo-chemically modified beech presents improved dimensional stability (> 60%) and better resistance against both Trametes versicolor and Reticulitermes flavipes compared to the control. However, at the same conditions, MOE and MOR values were lowered by approximately 25% and 60%, respectively.

Properties of Composite Panels Made from Secondary Fibers with Boric Acid

The change in the dimension (Thickness Swelling; TS) was found to be high, at high boric acid content for boards made from Office paper/Newspaper (O/N) and Office paper/Old Corrugated Container (O/C) types. However, the boards made with 10% boric acid exhibits higher Modulus of Rupture (MOR) values than boards made with 5.0% boric acid. The highest value of MOR was found as 7.93 MPa with the addition of 10% boric acid with Newspaper/Old Corrugated Containers (3:1 by weight) mixtures. The Modulus of Elasticity (MOE) of the boards generally decreased with increasing boric acid content from 5% to 10% in furnishes. The Office paper/Newspaper had the highest MOE among the all formulations and considerable higher than standard value of 600 MPa. However, the highest value of MOE was found as 735.63 MPa with the mixture of 3:1 (by weight) proportions of Office paper/Newspaper proportions. The similar results were observed for Internal Bond (IB) properties of boards, as like MOE. While in general, increasing boric acid content from 5.0 to 10%, negative effects on IB properties of boards. It was also realized that the boric acid content and fiber proportions effects various level on thermal properties (thermal conductivity; TC). The boric acid had usually provided higher thermal resistance, but the difference between fiber proportions and fiber types consisting of boric acid was important. However, the lowest TC value of 0.1455 W/mK was found the boards made from only old corrugated containers fibers with 10% BA content. The sound absorption values of boards made from secondary fibers show a sound damping that it was steady increase up to 1600 Hz and then decreasing. It could be realized that the sound absorption properties of boards were generally better than that of in lower frequencies.It was also realized that the boric acid content and fiber proportions effects various level on thermal properties (thermal conductivity; TC). The boric acid had usually provided higher thermal resistance, but the difference between fiber proportions and fiber types consisting of boric acid was important. However, the lowest TC value of 0.1455 W/mK was found the boards made from only old corrugated containers fibers with 10% BA content. The sound absorption values of boards made from secondary fibers show a sound damping that it was steady increase up to 1600 Hz and then decreasing. It could be realized that the sound absorption properties of boards were generally better than that of in lower frequencies.

Determination of Relationship between Thermal and Mechanical Properties of Wood Material

Non-destructive test techniques are becoming increasingly important for assessment and maintenance. These techniques are very useful for assessment of materials such as wood, whose performance can vary considerably depending on the conditions of use. It is possible to estimate some mechanical properties of a material by determining the movement of energy through the material with the help of these techniques. In this study, it was investigated whether the wood material could be tested nondestructively by the heat energy produced by a source. The correlations between the thermal conductivity and mechanical properties of Scots pine (Pinus sylvestris L.) and sessile oak (Quercus petraea L.) woods were investigated. The thermal conductivity (TC), density, modulus of rupture (MOR), compression strength (CS), and modulus of elasticity (MOE) values of samples were measured according to the related standards and these values were correlated with each other. The linear and multiple regression tests were employed to determine the correlation between thermal conductivity and mechanical properties. The results showed that there is a very strong correlation between thermal conductivity and both density and MOR values. However, the correlations between TC and both MOE and CS were moderate. The results of this study suggest that the thermal conductivity value can be used to estimate the density and some mechanical properties of wood.

Mechanical and Physical Properties of Particleboard from Untreated and Treated Kenaf Particles

Composite panels were manufactured from kenaf particles and treated with two different alkali treatments using 2% NaOH and 2% KOH with resin contents of 8% and 10% of phenol formaldehyde (PF) at medium density of 650kg/m3. The objectives of this study were to determine the mechanical properties in terms of its modulus of rupture (MOR), modulus of elasticity (MOE) and internal bond (IB), and physical properties namely thickness swelling (TS) and water absorption (WA) of treated kenaf board. The mechanical and physical tests were performed according to the Malaysian Standard (MS1787:2004). The minimum requirements value for MOE, MOR and IB were 2000 MPa, 14 MPa and 0.45 MPa respectively for furniture grade particleboards for use in humid conditions (PF2). According to Malaysian specifications for physical properties, the maximum requirement for thickness swell is 15%. Results indicated that both treated boards with NaOH and KOH showed an increase in strength properties compared to untreated particleboard. Particleboard treated with KOH exhibited the highest MOR and MOE values, while board with NaOH treatment gave the highest IB value. The boards with treated particles gave better performance in terms of physical properties. There were no significant differences in mechanical properties (MOR, MOE and IB) and physical properties for the different alkali treatment. The values of bending strength and IB strength increased with an increase in resin content, while TS and WA increased with a decrease in resin content. In conclusion, NaOH and KOH treated kenaf particles improved board performance and could be considered as an alternative material for particleboard production.

Optimum condition of manufacturing hybrid particleboard from mixture of cocoa pod husk and bamboo particles

This study was to investigate the feasibility of using cocoa pod husks (CPH) and bamboo in manufacturing hybrid particle board. Three-layer experimental particleboards from mixture of bamboo and CPH participles were manufactured using different surface to core layer ratios (30, 40 and 50%) and various UF ratios for surface layer (6, 8 and 10%) and for core layer (4, 6 and 8%). Modulus of rupture (MOR), internal bond strength (IB) and thickness swelling (TS) properties of the boards were evaluated based on Standard TCVN7756:2007 Test Methods for general purpose used in dry conditions. The results showed that boards in all ratios of surface to core layer investigated could be manufactured using up till 8% UF resin for surface layer and up till 6% UF resin for core layer without falling below the minimum Standard VN7754:2007. The optimal condition was the surface to core layer ratio of 30% used with 9.51% UF resin for surface layer and 7.45% UF resin for core layer obtaining the lowest thickness swelling (TS) 11.13%. The highest values of MOR and IB were 15.25 MPa and 0.45 MPa, respectively. This study demonstrates that cocoa pod husks and bamboo waste can be an alternative raw material source for particleboard production.

Comparison of different treatments based on glycerol or polyglycerol additives to improve properties of thermally modified wood

Impregnation of European beech (Fagus sylvatica) with 10% w/w aqueous solution of different additives made from the reaction of glycerol or polyglycerol with glycidyl methacrylate or maleic anhydride followed by thermal modification at 150, 200 or 220 °C under inert conditions was investigated to evaluate potential synergies between chemical and thermal treatments. Treated and untreated wood were analysed to evaluate mass changes and bulking values after treatments, resistance of treatment to leaching, wettability, anti-swelling efficiency, modulus of elasticity (MOE), modulus of rupture (MOR), decay resistance against Coriolus versicolor and termite resistance against Reticulitermes flavipes. Results revealed that synergic effects between a combination of light chemical modification and thermal treatments can be observed at higher temperature treatments (200 and 220 °C), improving wood dimensional stability (approximately 80%), decay, and termite resistance properties. However, MOE and MOR values decreased by approximately 30% and 60%, respectively. Treated samples resulting from the combination of chemical and thermal treatment performed at 220 °C present improved durability against the termites R. flavipes.

Fabrication of Fe3O4-modified lignocellulose composite for microwave absorption via a sol–gel-assisted hot-pressing process

An Fe3O4-modified lignocellulose (FeLC) composite was fabricated via a sol–gel-assisted hot-pressing process and used for microwave-absorbing and structural materials. The Fe3O4 nanoparticles could be formed in situ at the interface of the lignocellulose (LC) during sol–gel and hot-pressing processing. The obtained FeLC composites exhibited good mechanical and microwave absorption properties. The maximum reflection loss values of the FeLC composite reached − 10.97 dB at 17.04 GHz, and the effective electromagnetic wave absorption reached 90%. Compared with the modulus of rupture (MOR) and modulus of elasticity (MOE) of the LC composite, the maximum MOR and MOE values of the FeLC composite were 26.50 ± 1.16 MPa and 3.015 ± 0.25 GPa, respectively, increasing by 30.2% and 62.1%, respectively. Therefore, the properties of the FeLC could be enhanced via sol–gel assisted hot-pressing.

Response of coir fibre reinforced cement composites to water repellent chemical additive and microwave accelerated curing

The present investigation deals with performance of coir fibre reinforced cement boards subjected to matrix modification by silane-based water repellent chemical additive and microwave accelerated curing (MC). The fibre-cement boards were tested for water absorption, modulus of rupture (MOR) and modulus of elasticity (MOE). Scanning electron microscopy (SEM) and Fourier-transform infrared spectroscopy (FTIR) were used to characterize the composite samples. 84% reduction in water penetration was achieved through the use of the water repellent additive while MC samples had higher MOR and MOE values than the water cured samples. SEM characterization showed that MC provided good interfacial adhesion between the matrix and the reinforcement while the chemical additive reduced the occurrence of voids and pores on the surface. FTIR indicated prominent bands at 3423, 1425.44 and 875.41 cm−1 which are indicative of O–H stretching of the portlandite, C-H denoting the lignin deformation with aromatic ring stretching and C-O representing bend of carbonates. Therefore, MC and use of water repellent additive are recommended to improve the performance of cellulose fibre cement based applications.

Physical and Mechanical Properties Evaluation of Corncob and Sawdust Cement Bonded Ceiling Boards

This study considered the production of composite ceiling boards from both agricultural and industrial wastes. Boards with different blending proportions by weight of cement, corncob and sawdust (Cem:Ccb:Swd) were produced and tested. Physical and mechanical tests such as Water Absorption (WA), Thickness Swelling (TS), Modulus of Elasticity (MOE) and Modulus of Rupture (MOR) were carried out on the products. The findings revealed that the board with Cem:Ccb:Swd blending proportion 50:10:40 gave the highest values of MOE and MOR and also had the lowest values of WA and TS. The MOE and MOR values of 3.432 are both higher than the minimum values of 550 N/mm2 and 3 N/mm2 specified for MOE and MOR respectively by the American National Standard Institute, for general-use particle boards. The cement content is inversely proportional to the physical properties and directly proportional to the mechanical properties.

Flexural performance of cross-laminated timber constructed from fibre-managed plantation eucalyptus

This study was performed to evaluate the flexural performance of three-ply cross-laminated timber (CLT) floor panels made of unthinned and unpruned plantation Eucalyptus. The impact of the stress-grade of the timber boards on the modulus of elasticity (MOE) and modulus of rupture (MOR) of the panels was determined. The results indicated that the actual MOE of the timber boards from both species could not be appropriately estimated by visual stress-grading. The results revealed that the average MOE and MOR of the panels were significantly affected by the stress-grade of the boards in the top and bottom layers of the panels. The CLT panels made with high-grade boards showed respectively 24% and 21% higher MOE values than comparable panels made with low-grade boards for E. nitens and E. globulus. The failure modes were bending failure on the tensile side and rolling shear for the panels made of low-grade and high-grade boards, respectively. On average, the CLT panels made of E. globulus showed 17.7% higher MOE and 32.5% higher MOR values than comparable panels made of E. nitens.

Mechanical properties changes in oak (Quersus canariensis) and stone pine (Pinus pinea) wood subjected to various convective drying conditions

The aim of this article was to determine the effect of convective drying parameters on the mechanical properties of Oak (Quersus canariensis) and stone pine (Pinus pinea) wood boards (dimensions 20 × 50 × 300 mm−3). Dried wood samples were subjected to flexural and bending loading tests to determine the mechanical properties. Results indicated that drying time, modulus of rupture (MOR) and modulus of elasticity (MOE) of dried samples decreased with increasing drying temperature. Analysis of variance (ANOVA) showed that only the MOE of oak wood in axial compression test was affected by drying temperature. Means mechanical properties of dried woods boards were compared to those for air-natural drying revealing that convective drying at 55 °C has a lesser impact on mechanical characteristics of end product. Highest MOR and MOE means values in three-point static bending and axial compression tests of two woods were observed at 55 °C while the lowest means values were recorded at 85 °C. Results revealed that air-natural drying has a negative impact on the flexural and axial compression properties of two types of wood.

Mechanical characteristics of impregnated white Jabon wood ( Anthocephalus cadamba ) using merbau extractives and selected polymerised merbau extractives

This paper presents results of a study on the mechanical characteristics of impregnated Jabon wood (Anthocephalus cadamba) using Merbau extractives (ME) and two types of polymerised Merbau extractives (PME), i.e PME22 and PME33. A set of tests on hardness, shear, modulus of elasticity (MOE) and modulus of rupture (MOR) was conducted according to the relevant standards. Two types qualitative analysis by means of FTIR spectra and XRD analysis were carried out to explore relationship between the mechanical characteristics alteration with physico-chemical characteristics. The results indicated that a positive improvement in mechanical characteristics was obtained for Jabon wood impregnated with PME22 and PME33. Surface hardness of modified wood samples exhibited higher values compared to the non-impregnated samples for end and side hardness, by 20.04 and 30.54 % (PME22), and 32.73 and 39.89 (PME33), respectively. Shear strength increased by 41.87 and 49.58 % (PME22) and 74.02 and 79.10 % (PME) for radial (T) and tangential (T) sections, respectively. MOE increased by 23.52% (PME22) and by 40.12% (PME33), MOR values also increased by 28.50 and 41.19 % after impregnation with PME22 and PME33, respectively. The increment of mechanical propertiesof treated Jabon wood after impregnation treatment using polymerised Merbau extractives were confirmed by FTIR spectra and crystallinity (XRD) analysis.

Physico-Mechanical Properties of Particleboards Produced from Locally Sourced Materials

In this study, particleboard was produced from the blend of sawdust and rice husk with the inclusion of metallic chips and adhesives. Urea formaldehyde and gelatinous starch were used as adhesives. Particleboards (10 mm thickness) were made from varying weight percentage ratio of saw dust and rice husk using pressure in the neighbourhood of 3 N/mm2. The particleboard was tested to determine the density, modulus of rupture (MOR), modulus of elasticity (MOE) and internal bonding strength (IBS). The density of the particleboards developed varies from 762.86 to 801.60 kg/m3. The moisture content of the samples varied between 9.22% and 9.98%. The MOR, MOE and IB values varied between 5.08 MPa and 26.08 MPa; 75.38 MPa and 412.4 MPa; and 0.013 MPa to 0.07 MPa, respectively. Composite samples C, E and H values for MOR, MOE and IBS gave significant results which met with the EN, ANSI A 208.1 and USDA standards. Hence, the admixture of rice husk and sawdust together with UF adhesive will be suitable in producing particleboard that could be useful for indoor and outdoor purposes.

Mechanical and physical properties of the rice straw particleboard with various compositions of the epoxy resin matrix

The rice straw has been utilized to form particleboard by using an epoxy resin matrix. The rice straw particle (20 mesh) was mixed with epoxy resin with the various compositions, pressed with 5 ton of load to produce the rice straw particleboard samples. Mechanical and physical properties of rice straw particleboard were measured. Our results showed that the modulus of rupture (MOR) of rice straw particleboard is in the range of 2.07 to 3.31 kgf/mm2, the bending modulus of elasticity (MOE) is found to be 408 to 1490 kgf/mm2, and the density (ρ) is in the range of 0.360 to 0.480 g/cm3. We found that the MOR, MOE, and ρ have the exponential function of the resin composition with the equations of MOR = 2.0668 + 6.5604e−03327 x (kgf/mm2), MOE = 344.55 + 3159.5e−0203x (kgf/mm2), and p = 0.4414-0.3338e−02183 x (g/cm2), where x is the epoxy resin composition (%). This finding will help manufactory to produce rice straw particleboard for desired values of MOR, MOE, and density.

Improved Interfacial Interaction between Wood and Styrene with the Help of Organically Modified Nanoclay

Wood impregnated with styrene (ST) has a greater hydrophobicity than raw wood. Organically modified nanoclay can be used as a filler to increase the interfacial interaction between wood and ST. Raw wood shows an improved micro-structure, water uptake, modulus of rupture (MOR), modulus of elasticity (MOE), and thermal properties after impregnation with a mixture of i) non-branched organic ammonium-modified nanoclay (R-NH3+-clay) and ST; and ii) branched organic ammonium-modified nanoclay ((R)2N+(CH3)2-clay) and ST. Styrene with R-NH3+-clay-impregnated wood had a higher water uptake than the ST with (R)2N+(CH3)2-clay-impregnated wood. The MOE and MOR values of the ST with R-NH3+-clay-impregnated wood were higher than the ST with (R)2N+(CH3)2-clay-impregnated wood. Below 250 °C, the(R)2N+(CH3)2-clay with ST-impregnated wood had a greater thermal stability than the R-NH3+-clay with ST-impregnated wood.

STRENGTH AND STIFFNESS PROPERTIES OF SMALL CLEAR SPECIMENS TAKEN FROM COMMERCIALLY PROCURED NO.2 2×8 AND 2×10 SOUTHERN PINE DIMENSION LUMBER

This technical note focuses on the modulus of rupture (MOR) and modulus of elasticity (MOE) of small clear southern pine (Pinus spp.) test pieces cut from commercially procured full-size lumber specimens. A production-weighted sample of 476 No.2 grade 2×8s and 2×10s was acquired from retail establishments throughout the southern pine producing region. The specimens were subjected to static bending tests to measure MOR and MOE. From 447 of those specimens, a single small clear beam (3.8 × 3.8 × 61 cm) was extracted and subjected to a static bending test of the same properties. Two-sample t tests showed no evidence of statistical difference in either mean MOE or MOR between the small samples taken from the 2×8s and the 2×10s. Bivariate correlations and r2 values showed an overall weak relationship (r = 0.30, r2 = 0.09) between the small clears and their parent specimens in respect to MOR. A more moderate relationship (r = 0.60, r2 = 0.36) was found in respect to MOE between small clears and their parent specimens. In addition, a relatively strong relationship was found between the MOR and MOE values of the small clears themselves (r = 0.77, r2 = 0.59). It is intended that subsequent publications will examine similar relationships in other grades and sizes.

Study of the production process of 3-layer sugarcane-bamboo-based particleboards

This study evaluated the technical viability and performance of two different production processes of 3-layer sugarcane-bamboo-based particleboard (3LP) (3LP-PL: pressing in each layer; and 3LP-NPL: non-pressing in each layer) throughout their thermal, physical, mechanical and microstructural properties. The thermal conductivity was determined according to the methodology established by ASTM-E1530: 2011. Physical and mechanical properties were evaluated following the ABNT NBR 14810:2013 Brazilian Standards recommendations. Microstructural properties of the 3LP studied was assessed by using the Micro-CT technique. Thermal conductivity values of both 3LP were lower than the value required by Brazilian Standards for wood-based particleboards. Physical results indicated that the non-pressing in each layer during the 3LP production resulted in less thickness swelling (TS) and water absorption (WA). Modulus of rupture (MOR) and modulus of elasticity (MOE) of the 3LP-NPL showed an increase of 38 and 29% compared to the 3LP-PL respectively. Additionally, an increase of 31% was found for the internal bond (IB) value of the 3LP-NPL compared to the 3LP-PL. Considering the results achieved for the 3-layer sugarcane-bamboo-based particleboard the non-pressing in each layer during production presented lower TS and WA values and higher MOR, MOE and IB values.