scholarly journals The effect of moisture on the properties of cement-bonded particleboards made with non-traditional raw materials

2021 ◽  
Vol 67 (1) ◽  
Author(s):  
Tomas Melichar ◽  
Lenka Meszarosova ◽  
Jiri Bydzovsky ◽  
Matej Ledl ◽  
Silvestr Vasas
Keyword(s):  
Optical Microscopy ◽  
Raw Materials ◽  
Optical Microscope ◽  
Basic Material ◽  
Cement Matrix ◽  
Volume Changes ◽  
Air Voids ◽  
Effect Of Moisture ◽  
Property Changes ◽  
Standard Production

AbstractThe paper presents research into the changes of properties in cement-bonded particleboards caused by moisture saturation over the course of 504 h. Three particleboard variants were tested, all at the age of 18 months. The first is a standard production-line board manufactured by CIDEM Hranice, a.s. (identified as CP-R). The other two variants were modified by by-products of the particleboard manufacturing process—dust (CP-D) and a particulate mixture (CP-P). The experiment observed changes in the boards’ dimensions, volume, and mass. The effect of moisture on their basic material properties was also investigated. While the boards were being saturated by water, changes in their structure were examined using an optical microscope. It was found that the boards behave differently depending on their composition. Also there were differences in the dynamics of the property changes. The modified particleboards are more susceptible to dimensional and volume changes. Both, volume and mass undergo the most significant changes during the first 24 h. Cracks and air voids inside the wood chips begin to close upon contact with water as a result of swelling. It was observed by optical microscopy that this process occurs within 3 to 5 min since immersion in the water bath. Between 24 and 96 h the rate at which the air voids and pores are closing begins to decrease and there is a difference in the dynamics of mass and volume changes as well. Wet–dry cycling of the boards was analysed as well. Temperature and moisture fluctuations negatively affected particleboard behaviour and properties. Strength dropped up to 50%. Wider cracks in structure of the particleboards were detected by optical microscopy, namely in ITZ (internal transition zone) of cement matrix and spruce chips.

Research on Properties of Low Grade Cement-Based Composite Materials Modified by Silica Fume

2012 ◽  
Vol 174-177 ◽  
pp. 751-756
Author(s):  
Zi Fang Xu ◽  
Ming Xu Zhang ◽  
Jin Hua Li
Keyword(s):  
Silica Fume ◽  
Mechanical Performance ◽  
Raw Materials ◽  
Cement Matrix ◽  
Hardened Cement ◽  
Low Grade ◽  
X Ray ◽  
Matrix Microstructure ◽  
Nano Powder ◽  
Strength And Durability

In order to notably improve the mechanical properties and durability of low-grade cement-based material, superfine silica fume was used to modify the cement-based composite based on special perfomance and effects of nano powder. The mechanical performance and durability were investigated.Then the phase compositions,microstructure and morphologies of as-received cement-based composite were studied by X-ray Diffractometer、TGA-DTA and SEM. The results show that： the best formula of raw materials is 1:1:0.025:0.015, and hydration can be accelerated and increasing of hydration products is observed after modification. In the hardened cement matrix, microstructure is very compacted and C-S-H gel forms densed structure, so the structure defect is notably reduced. This means that both strength and durability of cement-based composite are notably improved by the addition of superfine silica fume.

scholarly journals Preparation of basalt-based glass ceramics

2003 ◽  
Vol 68 (6) ◽  
pp. 505-510 ◽  
Author(s):  
Branko Matovic ◽  
Snezana Boskovic ◽  
Mihovil Logar
Keyword(s):  
Optical Microscopy ◽  
Phase Analysis ◽  
Glass Ceramic ◽  
Glassy Phase ◽  
Raw Materials ◽  
Glass Ceramics ◽  
High Strength ◽  
Ceramic Materials ◽  
X Ray ◽  
Glass Ceramic Materials

Local and conventional raw materials?massive basalt from the Vrelo locality on Kopaonik mountain?have been used as starting materials to test their suitability for the production of glass-ceramics. Crystallization phenomena of glasses of the fused basalt rocks were studied by X-ray phase analysis optical microscopy and other techniques. Various heat treatments were used and their influences, on controlling the microstructures and properties of the products were studied with the aim of developing high strength glass-ceramic materials. Diopside CaMg(SiO3)2 and hypersthene ((Mg,Fe)SiO3) were identifies as the crystalline phases. The final products contained considerable amounts of a glassy phase. The crystalline size was in range of 8?480 ?m with plate or needle shape. Microhardness, crashing strength and wears resistence of the glass-ceramics ranged from 6.5?7.5, from 2000?6300 kg/cm2 and from 0.1?0.2 g/cm, respectively.

scholarly journals AN EFFECTIVE WAY TO RECYCLE 3D PRINTING CONCRETE SCRAP

2021 ◽  
Vol 4 (2) ◽  
pp. 12-18
Author(s):  
D.A. Tolypin ◽  
N. Tolypina
Keyword(s):  
Compressive Strength ◽  
3D Printing ◽  
Portland Cement ◽  
Quartz Sand ◽  
Raw Materials ◽  
Electricity Consumption ◽  
Cement Matrix ◽  
Fine Aggregate ◽  
Fine Grained ◽  
Control Samples

the article proposes a rational method for processing 3D printing concrete scrap using vibration equipment, which allows obtaining a multicomponent building material with minimal electricity consumption. As a crite-rion for the degree of grinding of concrete scrap, it is proposed to use the specific surface area of the finely dispersed part of concrete scrap, which should correspond to 400-500 m2/kg. The possibility of reusing the resulting product instead of the traditional fine aggregate of quartz sand is shown. It was found that the con-crete scrap without the addition of Portland cement hardens, reaching up to 48% of the compressive strength of the control samples by 28 days. When 10% of the binder CEM I 42.5 N was added to the concrete scrap processing product, the compressive strength of fine-grained concrete increased by 106.6%, and 20% of Portland cement - by 112.2 %, compared to the strength of control samples of a similar composition on tra-ditional quartz sand after 28 days of hardening. It is noted that this is primarily due to the weak contact zone of quartz sand and the cement matrix of concrete. The use of the product of processing concrete scrap al-lows obtaining building composites based on it with the complete exclusion of natural raw materials

Atomic Force Microscopy of Annealed Plain Carbon Steels

2015 ◽  
Author(s):  
Surendra Kumar Gupta ◽  
Patricia Iglesias Victoria
Keyword(s):  
Atomic Force Microscopy ◽  
Optical Microscopy ◽  
Interlamellar Spacing ◽  
Lamellar Spacing ◽  
Optical Microscope ◽  
Carbon Steels ◽  
Force Microscopy ◽  
Atomic Force

Microstructure of annealed plain carbon steels is examined using optical microscopy. When the inter-lamellar spacing in pearlite is small, optical microscope at 1000X is unable to resolve the ferrite and cementite lamellae. In hyper-eutectoid steels, cementite in pearlite appears as darker phase whereas the pro-eutectoid cementite appears as a lighter phase. Atomic force microscopy (AFM) of etched steels is able to resolve ferrite and cementite lamellae in pearlite at similar magnifications. Both cementite in pearlite as well as pro-eutectoid cementite appear as raised areas (hills) in AFM images. Interlamellar spacing in pearlite increases with increasing hardenability of steel.

Development of a Combined Scanning Ion-Conductance and Nearfield Optical Microscope to Image Living Cells

1999 ◽  
Vol 5 (S2) ◽  
pp. 976-977
Author(s):  
M. Raval ◽  
D. Klenerman ◽  
T. Rayment ◽  
Y. Korchev ◽  
M. Lab
Keyword(s):  
Optical Microscopy ◽  
Biological Samples ◽  
Near Field ◽  
Sample Surface ◽  
Optical Microscope ◽  
Ion Conductance ◽  
Simultaneous Generation ◽  
Simple Arrangement ◽  
Wavelength Resolution ◽  
Sub Wavelength

It is important to be able to image biological samples in a manner that is non-invasive and allows the sample to retain its functionality during imaging.A member of the SPM (scanning probe microscopy) family, SNOM (scanning near-field optical microscopy), has emerged as a technique that allows optical and topographic imaging of biological samples whilst satisfying the above stated criteria. The basic operating principle of SNOM is as follows. Light is coupled down a fibre-optic probe with an output aperture of sub-wavelength dimensions. The probe is then scanned over the sample surface from a distance that is approximately equal to the size of its aperture. By this apparently simple arrangement, the diffraction limit posed by conventional optical microscopy is overcome and simultaneous generation of optical and topographic images of sub-wavelength resolution is made possible. Spatial resolution values of lOOnm in air and 60nm in liquid[1,2] are achievable with SNOM.

scholarly journals Density Changes in Plutonium Observed from Accelerated Aging using Pu-238 Enrichment

2003 ◽  
Vol 802 ◽  
Author(s):  
B. W. Chung ◽  
S. R. Thompson ◽  
C. H. Woods ◽  
D. J. Hopkins ◽  
W. H. Gourdin ◽  
...  
Keyword(s):  
Accelerated Aging ◽  
Physical Property ◽  
Recoil Nucleus ◽  
Irradiation Damage ◽  
Volume Changes ◽  
Defect Clusters ◽  
Particle Decay ◽  
Lattice Damage ◽  
Property Changes ◽  
Inside Out

Plutonium, because of its radioactive nature, ages from the “inside out” by means of self-irradiation damage and thus produces Frankel-type defects (vacancies and self-interstitial atoms) and defect clusters. The self-irradiation damage in Plutonium-239 occurs mainly by α-particle decay, where most of the damage comes from the U-235 recoil nucleus. The defects resulting from the residual lattice damage and helium in-growth could result in microstructural and physical property changes. Because these self-irradiation effects would normally require decades to measure, with a fraction (7.5 wt%) of Pu-238 is added to the reference plutonium alloy thus accelerating the aging process by approximately 18 times the normal rate. By monitoring the properties of the Pu-238 spiked alloy over a period of about 3.5 years, the properties of plutonium in storage can be projected for periods up to about 60 years. This paper presents density and volume changes observed from the immersion density and dilatometry measurements equivalent to aging the reference plutonium alloys to nine years.

scholarly journals Production of Greener High-Strength Concrete Using Russian Quartz Sandstone Mine Waste Aggregates

Materials ◽  
2020 ◽  
Vol 13 (23) ◽  
pp. 5575
Author(s):  
Aleksandr Tolstoy ◽  
Valery Lesovik ◽  
Roman Fediuk ◽  
Mugahed Amran ◽  
Murali Gunasekaran ◽  
...  
Keyword(s):  
High Strength Concrete ◽  
Raw Materials ◽  
Mine Waste ◽  
Natural Radionuclides ◽  
High Strength ◽  
Morphological Properties ◽  
Cement Matrix ◽  
Natural Activity ◽  
Strength Concrete ◽  
The Cost

Quartz sandstone (QS) is a mine waste; therefore, its use in construction allows for both reducing the cost of the concrete and contributing to the utilization of waste. The scientific originality of this study is the identification of models of the effect of QS aggregate on the physicomechanical, durability characteristics, and eco-safety of greener high-strength concrete. The study used an energy-efficient method of non-thermal effects of electromagnetic pulses on the destruction mechanisms of quartz-containing raw materials. The characteristics of quartzite sandstone aggregates, including the natural activity of radionuclides, were comprehensively studied. The features of concrete hardening, including the formation of an interfacial transition zone between the aggregate and the cement matrix, were studied, taking into account the chemical and morphological features of quartzite sandstone. In addition, the microstructural and morphological properties of concrete were determined after a 28 day curing. In this study, the behaviors of the concrete with QS aggregate were investigated, bearing in mind the provisions of geomimetics science on the affinity of structures. The results obtained showed that the QS aggregate had the activity of natural radionuclides 3–4 times lower compared to traditional aggregates. Efficient greener concrete with a 46.3 MPa compressive strength, water permeability grade W14, and freeze–thaw resistance of 300 cycles were also obtained, demonstrating that the performance of this greener concrete was comparable to that of traditional concrete with more expensive granite or gabbro diabase aggregates.

scholarly journals Archaeometric Characterisation of Decorated Pottery from the Archaeological Site of Villa dei Quintili (Rome, Italy): Preliminary Study

Geosciences ◽  
2019 ◽  
Vol 9 (4) ◽  
pp. 172 ◽  
Author(s):  
Michela Ricca ◽  
Giuseppe Paladini ◽  
Natalia Rovella ◽  
Silvestro Antonio Ruffolo ◽  
Luciana Randazzo ◽  
...  
Keyword(s):  
Multidisciplinary Approach ◽  
Raw Materials ◽  
Archaeological Site ◽  
Optical Microscope ◽  
X Ray Diffraction ◽  
X Ray ◽  
Geochemical Study ◽  
Renaissance Period ◽  
Preliminary Study ◽  
Materials Used

This work focused on the study of decorated pottery dated back to the 16th century from the Roman archaeological site of Villa dei Quintili, a monumental complex located in the south-eastern part of Rome (Italy). A minero-petrographic and geochemical study was undertaken to analyse five archaeological samples in order to define textural features and raw materials used for their production, along with the chemical and physical composition of the superficial decorative glazed coatings. For this purpose, different analytical methods were used, such as polarising optical microscope (POM), X-ray diffraction (XRD), micro-Raman spectroscopy, X-Ray fluorescence (XRF), and electron microprobe analysis coupled with energy dispersive spectrometry (EMPA-EDS). The results of such a multidisciplinary approach allowed us to achieve important results crucial to recognise the shards as majolica of the Renaissance period, improving knowledge about manufacturing processes of these renowned painted ceramic artefacts.

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