scholarly journals Flexural characteristics of Eucalyptus nitens timber with high moisture content

BioResources ◽  
2021 ◽  
Vol 16 (2) ◽  
pp. 2921-2936
Author(s):  
Yingyao Cheng ◽  
Gregory Nolan ◽  
Damien Holloway ◽  
Jaskiran Kaur ◽  
Michael Lee ◽  
...  

The demand for timber resources in the building industry has been increasing. Plantation Eucalyptus nitens is of interest because of its sustainable supply and potential for structural applications. However, few design standards cover strength values of plantation eucalypt timber, especially flexural failure below and above the fibre saturation point, which is an important mechanism of failure in bending members used in the building industry. Static bending tests were undertaken using a universal testing machine to examine nonlinear bending behaviour of 130 fibre managed E. nitens small clear wood samples at low and high moisture contents (MC). The mean bending modulus of rupture (MOR) was 80.7 MPa for low MC and 59.0 MPa for high MC. The high MC samples exhibited larger displacements at low ultimate loads, while the low MC samples showed abrupt failures at relatively small displacements with high ultimate loads. The design characteristic values for low and high MC E. nitens were 68.5 MPa and 39.8 MPa, respectively. This research demonstrates that fibre managed E. nitens timber is a promising timber for structural applications, especially when exposed to water, as the MOR reduction of E. nitens timber above FSP is relatively lower than those of P. radiata, which is a traditional construction material.

2019 ◽  
Vol 2 (1) ◽  
pp. 221-224
Author(s):  
Tek Bahadur Katuwal

Concrete is fundamental construction material widely used for every building structure and other infrastructure. Aggregate has significantfunctions as concrete making materials for the solidity and strength of concrete.The objective of this research was comparative evaluation of crusher and river bed coarse aggregate in respect to the flexural strength of M20 grade concrete with nominal mix. For this research, sample were taken from Kotre Crusher(KC), Kotre River Bed (KR), Hemja Crusher (HC) and Hemja River Bed (HR) considering sand from single source and cement remains singlebrand.Nine cubes (500 mm × 100 mm×100mm) were cast for each sampled source and the flexural strength was determined using a single point load flexural testing machine after 7 days, 14 days and 28 days of curing. The mean flexural strength for the KC, KR, HC and HR sources were 4.86 N/mm2, 4.34 N/mm2, 4.58 N/mm2 and 4.1N/mm2, respectively. Also, the percentageincrement of flexural strength for KC, KR, HC and HR sources are 23.31, 19.11, 19.88 and 18.12 from 7 days to 14 days and 20.90, 16.04, 18.65 and 16.48 from 14 days to 28days respectively. Modulus of rupture of all aggregate sources are greater than theminimum flexural strength as per IS: 456 – 2000. Finally, outcomes of the study indicated that the flexural strength of Kotre Crusher aggregate is more than other sources and all selected samples applicable for construction work.


Forests ◽  
2019 ◽  
Vol 10 (2) ◽  
pp. 194 ◽  
Author(s):  
Mohammad Derikvand ◽  
Nathan Kotlarewski ◽  
Michael Lee ◽  
Hui Jiao ◽  
Gregory Nolan

The use of fast-growing plantation eucalypt (i.e., pulpwood eucalypt) in the construction of high-value structural products has received special attention from the timber industry in Australia and worldwide. There is still, however, a significant lack of knowledge regarding the physical and mechanical properties of the lumber from such plantation resources as they are mainly being managed to produce woodchips. In this study, the physical and mechanical properties of lumber from a 16-year-old pulpwood Eucalyptus nitens H.Deane & Maiden resource from the northeast of Tasmania, Australia was evaluated. The tests were conducted on 318 small wood samples obtained from different logs harvested from the study site. The tested mechanical properties included bending modulus of elasticity (10,377.7 MPa) and modulus of rupture (53 MPa), shear strength parallel (5.5 MPa) and perpendicular to the grain (8.5 MPa), compressive strength parallel (42.8 MPa) and perpendicular to the grain (4.1 MPa), tensile strength perpendicular to the grain (3.4 MPa), impact bending (23.6 J/cm2), cleavage (1.6 kN) and Janka hardness (23.2 MPa). Simple linear regression models were developed using density and moisture content to predict the mechanical properties. The variations in the moisture content after conventional kiln drying within randomly selected samples in each test treatment were not high enough to significantly influence the mechanical properties. A relatively high variation in the density values was observed that showed significant correlations with the changes in the mechanical properties. The presence of knots increased the shear strength both parallel and perpendicular to the grain and significantly decreased the tensile strength of the lumber. The results of this study created a profile of material properties for the pulpwood E. nitens lumber that can be used for numerical modelling of any potential structural product from such a plantation resource.


2021 ◽  
Vol 104 (2) ◽  
pp. 003685042110294
Author(s):  
Khaled Abd El-Aziz ◽  
Emad M Ahmed ◽  
Abdulaziz H Alghtani ◽  
Bassem F Felemban ◽  
Hafiz T Ali ◽  
...  

Aluminum alloys are the most essential part of all shaped castings manufactured, mainly in the automotive, food industry, and structural applications. There is little consensus as to the precise relationship between grain size after grain refinement and corrosion resistance; conflicting conclusions have been published showing that reduced grain size can decrease or increase corrosion resistance. The effect of Al–5Ti–1B grain refiner (GR alloy) with different percentages on the mechanical properties and corrosion behavior of Aluminum-magnesium-silicon alloy (Al–Mg–Si) was studied. The average grain size is determined according to the E112ASTM standard. The compressive test specimens were made as per ASTM: E8/E8M-16 standard to get their compressive properties. The bulk hardness using Vickers hardness testing machine at a load of 50 g. Electrochemical corrosion tests were carried out in 3.5 % NaCl solution using Autolab Potentiostat/Galvanostat (PGSTAT 30).The grain size of the Al–Mg–Si alloy was reduced from 82 to 46 µm by the addition of GR alloy. The morphology of α-Al dendrites changes from coarse dendritic structure to fine equiaxed grains due to the addition of GR alloy and segregation of Ti, which controls the growth of primary α-Al. In addition, the mechanical properties of the Al–Mg–Si alloy were improved by GR alloy addition. GR alloy addition to Al–Mg–Si alloy produced fine-grained structure and better hardness and compressive strength. The addition of GR alloy did not reveal any marked improvements in the corrosion properties of Al–Mg–Si alloy.


2013 ◽  
Vol 795 ◽  
pp. 684-691 ◽  
Author(s):  
Wail N. Al-Rifaie ◽  
Omar Mohanad Mahdi ◽  
Waleed Khalil Ahmed

The present research examined the compressive and flexural strength of nanocement mortar by using micro cement, micro sand, nanosilica and nanoclay in developing a nanocement mortar which can lead to improvements in ferrocement construction. The measured results demonstrate the increase in compressive and flexural strength of mortars at early stages of hardening. In addition, the influence of heating on compressive strength of cement mortar. General expressions to predict the compressive strength, modulus of rupture for the developed nanocement mortar in the present work are proposed.


2020 ◽  
Vol 12 (24) ◽  
pp. 10469
Author(s):  
Manuel Ferrandez-Villena ◽  
Antonio Ferrandez-Garcia ◽  
Teresa Garcia-Ortuño ◽  
Clara Eugenia Ferrandez-Garcia ◽  
Maria Teresa Ferrandez Garcia

Agriculture is responsible for generating large amounts of waste that are not adequately managed in terms of their environmental treatment and economic administration. This work uses giant reed, which was traditionally used as a construction material in eastern areas of Spain. Nowadays, it is no longer used, which has led to its rapid, autonomous, uncontrolled proliferation on river banks, making it a serious environmental hazard because this plant causes significant blockages of bridges and other infrastructure when uprooted by the strong currents that occur as rivers flood. The aim of this work is to develop wood and giant reed particleboards, which help to counter the high dependence on wood in industrial manufacturing by using an easily renewable resource. It will thereby be possible to achieve two general objectives: controlling the growth of a weed and obtaining a product (particleboards) from a waste material. Particleboards containing 9% urea formaldehyde composed of different proportions of sawmill wood and giant reed (0, 50, 70 and 100%) have been manufactured by applying two different pressures (2.1 and 2.6 MPa) and a temperature of 120 °C for 4 min in a hot plate press. Density, thickness swelling (TS) and water absorption (WA) after immersion in water, modulus of elasticity (MOE), modulus of rupture (MOR), internal bonding strength (IB) and screw holding strength (SH) have been tested according to european norms (EN) for wood boards. With the addition of 70% reed particles, the density, MOR and TS decrease and the MOE, IB and SH increase; therefore, adding giant reed particles to wood boards can improve their properties, bringing about considerable industrial and environmental benefits.


Proceedings ◽  
2018 ◽  
Vol 2 (20) ◽  
pp. 1296
Author(s):  
Diogo T. Moreira ◽  
Arno H. Oliveira ◽  
Adriana S. M. Batista

Present day steelmaking slags are being successfully used as a high quality mineral aggregate for the building industry. With this, it is of vital importance to be familiar with the technical significance of the secondary application of steel slag, because some steel slag might contain increased concentration of substances harmful to human health. In terms of steel slag impact on the environment, radionuclides are the least researched of all pollutants emitted from the metallurgical processes. This work presents the preliminary study about the presence of the uranium in siderurgy slag aggregates for the purpose of its use in the production of construction material. The results showed that this slag is free of uranium which brings greater security in its use as building material.


Materials ◽  
2019 ◽  
Vol 12 (16) ◽  
pp. 2607 ◽  
Author(s):  
Chenhua Jin ◽  
Chang Wu ◽  
Chengcheng Feng ◽  
Qingfang Zhang ◽  
Ziheng Shangguan ◽  
...  

Strain-hardening cementitious composite (SHCC) is a kind of construction material that exhibits multiple cracking and strain-hardening behaviors. The partial replacement of cement with fly ash is beneficial to the formation of the tensile strain-hardening property of SHCC, the increase of environmental greenness, and the decrease of hydration heat, as well as the material cost. This study aimed to develop a sustainable construction material using a high dosage of fly ash (no less than 70% of the binder material by weight). Based on the micromechanics analysis and particle size distribution (PSD) optimization, six mixes with different fly ash to cement ratios (2.4–4.4) were designed. The mechanical properties of the developed high-volume fly ash SHCCs (HVFA-SHCCs) were investigated through tensile tests, compressive tests, and flexural tests. Test results showed that all specimens exhibited multiple cracking and strain-hardening behaviors under tension or bending, and the compressive strength of the designed mixes exceeded 30MPa at 28 days, which is suitable for structural applications. Fly ash proved to be beneficial in the improvement of tensile and flexural ductility, but an extremely high volume of fly ash can provide only limited improvement. The HVFA-SHCC mix FA3.2 (with fly ash to binder ratio of about 76% by weight) designed in this study is suggested for structural applications.


2018 ◽  
Vol 85 (7) ◽  
Author(s):  
Andrea K. I. Hall ◽  
Thomas C. O'Connor ◽  
Molly K. McGath ◽  
Patricia McGuiggan

Brittleness in paper is one of the primary reasons library books are removed from circulation, digitized, or have their access limited. Yet, paper brittleness is difficult to characterize as it has multiple definitions and no single measurable physical or chemical property associated with it. This study reevaluates the cantilever test as applied to aged papers. In this nondestructive test, the deflection of a strip of paper held horizontally is measured across its length. The deflection data are then fit to nonlinear bending theories assuming large deflection of a cantilever beam under a combined uniform and concentrated load. Fitting the shape of the deflection profiles provides bending and elastic moduli, the bending length, and confirms that the paper sheets respond linearly. The results are compared to those calculated from a simplified single point measurement of the maximum deflection of the cantilevered sample. Young's modulus measured by the cantilever test is lower for paper-based materials than that measured by tensile testing, and the bending modulus was found to correlate with the destructive Massachusetts Institute of Technology (MIT) fold endurance test.


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