scholarly journals Mechanical performance of Scots pine wood from northwestern Poland – A case study

BioResources ◽  
2020 ◽  
Vol 15 (3) ◽  
pp. 6781-6794
Author(s):  
Edward Roszyk ◽  
Przemysław Mania ◽  
Elżbieta Iwańska ◽  
Władysław Kusiak ◽  
Magdalena Broda
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Scots Pine ◽  
Mechanical Performance ◽  
Raw Material ◽  
Site Conditions ◽  
Commercially Important ◽  
Growing Conditions ◽  
Northwestern Poland

Scots pine is one of the most commercially important wood species in Europe. This study assessed the potential usefulness of pinewood from the Noteć Forest for construction purposes by evaluating its mechanical properties and investigating the influence of the site conditions on the pinewood performance. Additionally, the variability of the mechanical properties from the bark to the pith was analyzed. The results showed that the properties of pinewood varied significantly within the Noteć Forest despite similar growing conditions, which may be a result of genetic variation. Wood from Sowia Góra had the greatest density (566 kg/m3) and excellent mechanical performance (compressive strength of 64 MPa), while wood from Zamyślin exhibited the lowest density (526 kg/m3) and a lower compressive strength (54 MPa). Comparison of the properties of the pinewoods from various locations indicated that the general conditions in the forest stand, however crucial for tree growth, were not the only determinants of wood performance. The results also showed high variability in density and mechanical properties between juvenile and mature wood in all the examined trees. Overall, pinewood from the poor habitats of the Noteć Forest could be a useful raw material for various industrial purposes.

scholarly journals Influence of Glass Fibers on Mechanical Properties of Concrete with Recycled Coarse Aggregates

2019 ◽  
Vol 5 (5) ◽  
pp. 1007-1019 ◽  
Author(s):  
Babar Ali ◽  
Liaqat Ali Qureshi ◽  
Ali Raza ◽  
Muhammad Asad Nawaz ◽  
Safi Ur Rehman ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Flexural Strength ◽  
Mechanical Performance ◽  
Volume Fraction ◽  
Glass Fibers ◽  
Construction Material ◽  
Concrete Compressive Strength ◽  
Coarse Aggregates ◽  
Highly Sensitive

Despite plain cement concrete presenting inferior performance in tension and adverse environmental impacts, it is the most widely used construction material in the world. Consumption of fibers and recycled coarse aggregates (RCA) can add ductility and sustainability to concrete. In this research, two mix series (100%NCA, and 100%RCA) were prepared using four different dosages of GF (0%GF, 0.25%GF, 0.5%GF, and 0.75%GF by volume fraction).  Mechanical properties namely compressive strength, splitting tensile strength, and flexural strength of each concrete mixture was evaluated at the age of 28 days. The results of testing indicated that the addition of GF was very useful in enhancing the split tensile and flexural strength of both RCA and NCA concrete. Compressive strength was not highly sensitive to the addition of GF. The loss in strength that occurred due to the incorporation of RCA was reduced to a large extent upon the inclusion of GF. GF caused significant improvements in the split tensile and flexural strength of RCA concrete. Optimum dosage of GF was determined to be 0.25% for NCA, and 0.5% for RCA concrete respectively, based on the results of combined mechanical performance (MP).

scholarly journals Mechanical Performance and Microscopic Mechanism of Coastal Cemented Soil Modified by Iron Tailings and Nano Silica

Crystals ◽  
2021 ◽  
Vol 11 (11) ◽  
pp. 1331
Author(s):  
Xinjiang Song ◽  
Haibo Xu ◽  
Deqin Zhou ◽  
Kai Yao ◽  
Feifei Tao ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Mechanical Performance ◽  
Hydration Reaction ◽  
Unconfined Compression ◽  
Nano Silica ◽  
Microscopic Mechanism ◽  
Clay Particles ◽  
Soil Cement ◽  
Cement Soil

In order to explore the effect of composite materials on the mechanical properties of coastal cement soil, cement soil samples with different iron tailings and nano silica contents were prepared, and unconfined compression and scanning electron microscope tests were carried out. The results show that: (1) The compressive strength of cement soil containing a small amount of iron tailings is improved, and the optimum content of iron tailings is 20%. (2) Nano silica can significantly improve the mechanical properties of iron tailings and cement soil (TCS). When the content of nano silica is 0.5%, 1.5%, and 2.5%, the unconfined compressive strength of nano silica- and iron tailings-modified cement soil (STCS) is 24%, 137%, and 323% higher than TCS, respectively. (3) Nano silica can promote the hydration reaction of cement and promote the cement hydration products to adhere to clay particles to form a relatively stable structure. At the same time, nano silica can fill the pores in TCS and improve the compactness of STCS.

scholarly journals Factors That Affect the Mechanical Strength of Archaeological Wood—A Case Study of 18th-Century Wooden Water Pipes from Bóżnicza Street in Poznań, Poland

Materials ◽  
2021 ◽  
Vol 14 (24) ◽  
pp. 7632
Author(s):  
Magdalena Broda ◽  
Carmen-Mihaela Popescu ◽  
Daniel Ilie Timpu ◽  
Dawid Rowiński ◽  
Edward Roszyk
Keyword(s):  
Mechanical Properties ◽  
Chemical Composition ◽  
Mechanical Strength ◽  
Wood Density ◽  
Mechanical Performance ◽  
Cellulose Crystallinity ◽  
Compression Tests ◽  
Substantial Impact ◽  
Archaeological Wood

Large amounts of archaeological wood are often excavated during groundworks in cities and towns. Part of the unearthed artefacts is usually saved, conserved and then presented in museums. However, if the finding contains several similar objects, some of them could potentially be further employed for some other practical purposes. The research aimed to determine the mechanical performance of the remains of wooden water mains excavated at Bóżnicza street in Poznań, Poland and evaluate its potential usefulness for any practical purposes. First, wood density was determined along with its mechanical strength in compression. The density of archaeological wood identified as Scots pine was lower than contemporary pinewood (383 kg × m−3 vs. 572 kg × m−3); therefore, its mechanical properties in compression tests were also lower, as expected, making the wood unsuitable for any practical applications. However, the differences in modulus of elasticity and compressive strength were not justified by the differences in wood density. Further infrared spectroscopy and X-ray diffraction analyses revealed additional differences in chemical composition and cellulose crystallinity between archaeological and contemporary wood. The results indicated the decrease in carbohydrate content and cellulose crystallinity in degraded wood, which, in addition to wood density, apparently contribute to the deterioration in mechanical strength of archaeological wood. The case study of the excavated archaeological wooden pipes shows that they have historical value but are not useful for practical purposes. It also revealed that not only wood density but also its chemical composition and cellulose crystallinity level has a substantial impact on the wood mechanical properties, particularly in compression.

scholarly journals THE CONSTRUCTION OF A COMPOSITION BASED ON MAGNESIA BINDER WITH PEAT

Vestnik MGSU ◽  
2017 ◽  
pp. 642-646
Author(s):  
Natalia Shamilievna Lebedeva ◽  
Evgeniy Gennadievich Nedayvodin
Keyword(s):  
Mechanical Properties ◽  
Aqueous Solution ◽  
Compressive Strength ◽  
Building Material ◽  
Construction Material ◽  
Raw Material ◽  
Sound Insulation ◽  
Structural Purpose ◽  
Different Content ◽  
Good Heat

Obtained building material based on magnesia binder with different content of peat (0 to 90 %), on a specially developed technique. As a binder used PMK 87, for mixing mixtures used aqueous solution of magnesium chloride and peat from the Ivanovo region. It were determined such physical and physico-mechanical properties of the investigated material as the compressive strength and the density. The strength characteristics of silicate bricks, ceramic bricks and the investigated material based on magnesia binder and peat was analyzed and compared. It is established that the samples of construction material with content of peat not exceeding 40 wt.% can be attributed to the materials of structural purpose by its compressive strength. Samples of the material with content of the peat 40% have a density 943,75 kg/m3, that provides good heat and sound insulation properties. It is revealed that the solution of the raw material mixture of magnesia binder, peat, the solution of bischofite is optimized to place, and the material gets at least 85% of its strength during 30 days.

High-Effective Lightweight Aggregate Obtained from Glass-Containing Waste

2020 ◽  
Vol 787 (12) ◽  
pp. 66-71
Author(s):  
H.N. Mammadov ◽  
◽  
I.H. Suleymanova ◽  
B.M. Tahirov ◽  
◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Strength Class ◽  
Physical And Mechanical Properties ◽  
Lightweight Aggregate ◽  
High Strength ◽  
Raw Material ◽  
Material Base ◽  
Current Standard ◽  
Iron And Steel

The properties of high-strength artificial porous aggregate from glass-containing waste of metallurgical productions are described. The developed technology makes it possible to expand the raw material base for the production of aggregates for light concrete. Granulated slags of metallurgical productions – the main (M0>1) slags of the Novokuznetsk Iron and Steel Plant and acid (M0<1) slags of the Gorky plant are studied. According to the results of studies, it was found that the optimal swelling interval for acidic slags is 1000–1100оC, and for basic slags-1100–1150оC. A high – strength artificial porous aggregate-slag gravel with a bulk density of 340–780 kg/m3 and a compressive strength in the cylinder of 2.8–12.3 MPa was obtained. The main physical and mechanical properties of the resulting aggregate, which meets the requirements of the current standard GOST 9757–90 “Gravel, crushed stone and sand. Artificial porous”, were studied. The aggregate obtained is almost twice as strong as the known aggregate of expanded clay gravel. With the use of porous gravel and sand, light concrete of strength class B7,5–B40 and a density of 1100–1600 kg/m3 was obtained.

scholarly journals Elastic Mechanical Properties of 45S5-Based Bioactive Glass–Ceramic Scaffolds

Materials ◽  
2019 ◽  
Vol 12 (19) ◽  
pp. 3244 ◽  
Author(s):  
Francesco Baino ◽  
Elisa Fiume
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Elastic Modulus ◽  
Shear Modulus ◽  
Glass Ceramic ◽  
Poisson’S Ratio ◽  
Mechanical Performance ◽  
Poisson's Ratio ◽  
Shear Moduli ◽  
Bioactive Scaffolds

Porosity is recognized to play a key role in dictating the functional properties of bioactive scaffolds, especially the mechanical performance of the material. The mechanical suitability of brittle ceramic and glass scaffolds for bone tissue engineering applications is usually evaluated on the basis of the compressive strength alone, which is relatively easy to assess. This work aims to investigate the porosity dependence of the elastic properties of silicate scaffolds based on the 45S5 composition. Highly porous glass–ceramic foams were fabricated by the sponge replica method and their elastic modulus, shear modulus, and Poisson’s ratio were experimentally determined by the impulse excitation technique; furthermore, the failure strength was quantified by compressive tests. As the total fractional porosity increased from 0.52 to 0.86, the elastic and shear moduli decreased from 16.5 to 1.2 GPa and from 6.5 to 0.43 GPa, respectively; the compressive strength was also found to decrease from 3.4 to 0.58 MPa, whereas the Poisson’s ratio increased from 0.2692 to 0.3953. The porosity dependences of elastic modulus, shear modulus and compressive strength obeys power-law models, whereas the relationship between Poisson’s ratio and porosity can be described by a linear approximation. These relations can be useful to optimize the design and fabrication of porous biomaterials as well as to predict the mechanical properties of the scaffolds.

scholarly journals Effect of Additives on the Rheological and Mechanical Properties of Microfine-Cement-Based Grout

2019 ◽  
Vol 2019 ◽  
pp. 1-10
Author(s):  
Shuai Zhang ◽  
Weiguo Qiao ◽  
Yanzhi Li ◽  
Kai Xi ◽  
Pengcheng Chen
Keyword(s):  
Mechanical Properties ◽  
Particle Size ◽  
Compressive Strength ◽  
Fly Ash ◽  
Mechanical Performance ◽  
Setting Time ◽  
Effect Of Additives ◽  
Microfine Cement ◽  
The Stability ◽  
Grouting Materials

Enhancement of the fluidity and mechanical performance of grouting materials has proven to be an effective method of seepage prevention in geotechnical engineering. In this research, a microfine-cement-based grout mixed with microfine fly ash (MFA), nano-CaCO3 (NC), and superplasticizer (SP) was designed to improve the rheological and mechanical properties of grouting materials, and the particle size distribution, fluidity, spreading ability, bleed capacity, setting time, and mechanical properties were studied. A water/solid (W/S) ratio of 1.2 was selected, and the contents of MFA, NC, and SP by mass of microfine cement (MC) were 0–40%, 0–2.0%, and 1.5%, respectively. The results showed that MFA and 1.5% SP improved the fluidity and spreading ability of fresh grouts, while prolonging the setting time. The addition of NC can increase the yield stress and plastic viscosity and decrease the fluidity and spreading ability; nevertheless, it obviously enhances the stability and shortens the setting time of grouts. The addition of MFA and 1.5% SP reduced the compressive strength of hardened grouts; however, the addition of NC improved the mechanical properties.

scholarly journals Feasibility of Developing Sustainable Concrete Using Environmentally Friendly Coarse Aggregate

2020 ◽  
Vol 10 (15) ◽  
pp. 5207
Author(s):  
Chamila Gunasekara ◽  
Charitha Seneviratne ◽  
David W. Law ◽  
Sujeeva Setunge
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Coarse Aggregate ◽  
Mechanical Performance ◽  
Drying Shrinkage ◽  
Strength Development ◽  
Design Strength ◽  
Coarse Aggregates ◽  
Increasing Demand ◽  
Quality Material

Quarry aggregate reserves are depleting rapidly within Australia and the rest of the world due to an increasing demand for aggregates driven by expansion in construction. The annual production of premix concrete in Australia is approximately 30 million cubic meters, while 3–5% of concrete delivered to site remains unused and is disposed of in landfill or crushing plants. The production of coarse aggregates using this waste concrete is potentially a sustainable approach to reduce environmental and economic impact. A testing program has been conducted to investigate mechanical performance and permeation characteristics of concrete produced using a novel manufactured coarse aggregate recycled directly from fresh premix concrete. The recycled coarse aggregate (RCA) concrete satisfied the specified 28-day design strength of 25 MPa and 40 MPa at 28 days and a mean compressive strength of 60 MPa at 90 days. Aggregate grading was observed to determine strength development, while low water absorption, low drying shrinkage, and higher packing density indicate that the RCA concrete is a high-quality material with a dense pore structure. The rough fracture surface of the aggregate increased the bond between C-S-H gel matrix and RCA at the interfacial transition zone. Furthermore, a good correlation was observed between compressive strength and all other mechanical properties displayed by the quarried aggregate concrete. The application of design equations as stated in Australian standards were observed to provide a conservative design for RCA concrete structures based on the mechanical properties.

Application of New Soil Consolidator in Road-Construction Engineering

2012 ◽  
Vol 238 ◽  
pp. 466-469
Author(s):  
Hong Zhang ◽  
Dong Liang Xun ◽  
Zhao Yang ◽  
Fu Quan Ji
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Physical And Mechanical Properties ◽  
Road Construction ◽  
Point Of View ◽  
Curing Time ◽  
Construction Engineering ◽  
Geological Conditions ◽  
Silt Layer

This paper contrastively analyses the consolidation instances of silt with HEC and HAS soil consolidators, also emphatically discusses the influence regularities of the compressive strength of solidified soil with the following factors: the dose of consolidators and the curing time. Meanwhile, from the point of view of experiment, this paper studies the physical and mechanical properties of solidified soil. Case study shows that HEC and HAS soil consolidators behave as well as cement and lime in road-construction engineering, and even that filling subgrade independently. Also, this paper proposes the appropriate value 6% of HEC and HAS soil consolidators for solidifying silt layer, which can be used as reference for the similar geological conditions.

scholarly journals Influence of the Composition and Curing Time on Mechanical Properties of Fluidized Bed Combustion Fly Ash-Based Geopolymer

Polymers ◽  
2021 ◽  
Vol 13 (15) ◽  
pp. 2527
Author(s):  
Natalia Wielgus ◽  
Jan Kubica ◽  
Marcin Górski
Keyword(s):  
Mechanical Properties ◽  
Compressive Strength ◽  
Fly Ash ◽  
Fluidized Bed ◽  
Environmentally Friendly ◽  
Raw Material ◽  
Fluidized Bed Combustion ◽  
Precast Elements ◽  
Ash Disposal ◽  
Fbc Fly Ash

This paper presents novel research on a fluidized bed combustion (FBC) fly ash-based geopolymer as a contribution to the problem of FBC fly ash disposal, and a proposal for a new geopolymer composition—an environmentally friendly material that is possible to use in construction. Geopolymer samples of various composition (containing FBC fly ash as the main raw material, metakaolin and CRT glass as additional components, and sodium silicate and sodium hydroxide as activators) were subjected to flexural and compressive strength tests. An investigation on the effect of the demolding time was carried out on one selected mixture. The test showed that both the composition and the demolding time have a decisive influence on the basic mechanical properties. A mixture containing FBC fly ash to metakaolin in a mass ratio of 3:1, removed from the mold after 14 days, was found to be the best in terms of the mechanical parameters expected from a material that could be used in construction, e.g., for the production of precast elements. According to the results obtained, FBC fly ash is a promising and environmentally friendly raw material for the production of geopolymer, with good mechanical properties and low density. Moreover, a high compressive strength can be obtained by curing the geopolymer at ambient temperature.

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