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No coal samples were tested due to their unavailability. The possibility of estimating UCS (uniaxial compressive strength) from P-wave velocity is highlighted, with a high coefficient of determination (R 2 close to 0.90) for sandstones, using the two indirect methods investigated.
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when the compressive stress is equal to zero. In the equation 0), if s=O, then C=-Po tan cp or Po = -c/tan cp, where Po is equivalent to the soil internal stress at the shear surface. Such a relation is illustrated in Figure 1. ..c. c ~I ; Shear strength line 1 Shear T cohesion (C L 0 Compressive stress (P)
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Figure 1. The Point Load Tester. USING THE POINT LOAD TEST TO DETERMINE THE UNIAXIAL COMPRESSIVE STRENGTH OF COAL MEASURE ROCK John Rusnak, Director of Geology Peabody Group St. Louis, MO Christopher Mark, Rock Mechanics Team Leader National Institute for Occupational Safety and Health Pittsburgh, PA ABSTRACT Point load testing is used to determine rock strength indexes in geotechnical practice.
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The compressive strength strongly depended on the moisture content, i.e ., the strength increased from 21 to 65 MPa or higher as the moisture content decreased to critical values, after which the strength began to decrease. The results showed that microwave energy stimulated an additional geopolymerization by evaporating the redundant free water.
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Untreated coal waste has a dry unit weight of 1.24 g/cm 3, compressive strength of about 25 MPa, and fineness modulus of about 2.9. The chemical properties and the gradation curves of both replacement levels of waste coal used in this study are presented in Table 2 and Figure 1, respectively.
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Unconsolidated, Undrained Compressive Strength of Cohesive Soils in Triaxial Compression Consolidated, Undrained Triaxial Compression Test on Cohesive Soils Moisture/Density Relations of Soils Using a 4.54 Kg Hammer and a 457 mm Drop Specific Gravity of Soils Torvane Shear/Soil Pocket Penetrometer Determining pH of Soil for Use in Corrosion Testing
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The purposes of this paper are to adopt the standard for test methods of basic mechanical properties of masonry for different type coal gangue perorated with multiform holes masonry in axis compression test and discuss the crevice and destruction features for this masonry. We analyzed its compressive capacity,elastic modulus and stress-strain relationship though the compression test of ...
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investigation on the compressive strength of field collected Table -6: Calculated PSI and σ c for S 5 Sample minimum of 0.12 MPa PSI Compressive strength (σc) in MPa S5 8.333 0.159 9.090 0.216 10 0.252 14.814 0.239 20 0.230 The obtained values of PSI and compressive strength of coal depicts that these values increase with the increase number
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Therefore, the Unconfined Compressive Strength is calculated for the maximum load applied: σ UCS = P max / A 0 The modulus of elasticity (Young's modulus) E which represents the ratio between axial stress and axial strain can be derived via several methods. Usually, it is calculated at stress-strain level of about 50% of the maximum load.
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Table 1.1 Example Core Tests Results. Notice that a series of coring samples are obtained as per table 1.1. According to ACI 318, as stated in ACI 214-4R-03 Chapter 7, the suspected concrete is considered adequate if the average corrected strength of the three cores exceeds 0.85fc' and no individual strength is lesser than 0.75fc'. Therefore to calculate the compressive strength fc' for ...
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Comparing Compressive Strength of Alkali-Activated Coal Fly Ash to Natural Pozzolans. ASTM International Committee C01 on Cement is developing a proposed standard that will be used to help create data for comparing the compressive strength of alkali activated fly ash and natural pozzolans.. ASTM WK42602, Test Method for Compressive Strength of Alkali Activated Coal Fly Ash and Raw or Calcined ...
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Finite-size effect on multiaxial compressive strength for coal (experimental data). These strength values have been recalculated using the generalized Hoek and Brown empirical formulation (equation 1 of ref. 34) and using the set of parameters found in table 3 of the same ref. 34, for confining pressure σ 3 = 0 MPa, 2
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uniaxial compressive strength measurements made on core samples from the same holes. In McNally's classic original study, conducted in 1987, sonic velocity logs and drill core were obtained from 16 mines throughout the Australian coalfields. The overall correlation equation McNally obtained from least-squares regression was: UCS = 143,000 x e
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Advanced testing tests for other parameters, such as splitting strength, shear strength, and high-temperature compression strength. Sand control. Green sand is made up of basic sand (shell sand), bentonite or another binder, pitch powder or coal dust, and uninvited dust. Green sand properties cannot be standardized for all foundries and ...
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From the NIOSH coal database, Mark and Barton (1996), the uniaxial compressive strength of Appalachian Basin coal seams with N > 40, the standard deviation expressed as a percentage of the mean...
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In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are dependent upon rock type. This study involved the extensive load frame and point load testing of coal measure rocks in six states.
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The compressive strength and flexural strength of the reference group were 35 MPa and 4.72 MPa, respectively; when the aerogel content was 80%, the compressive strength and flexural strength were 0.82 MPa and 0.68 MPa, respectively, a decrease of 97.66% and 85.69%, respectively.
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The dilatation coefficient, cohesive strength, and compression strength of this adhesive exceed 1, 3.0 N/mm 2 and 45 N/mm 2, respectively. High-polymer material has many advantages compared to its alternatives, ... Hence, another factor increased the strength of the coal. The reason could be linked with the porosity of the coal .
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this conference paper was originally published as colwell, m and frith, r, why uniaxial compressive strength and young's modulus are commonly poor indicators of roadway roof stability - except in the tailgate, in aziz, n (ed), coal 2006: coal operators' conference, university of wollongong & the australasian institute of mining and metallurgy, .
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The addition of 13.7cc biological activator per litre of water reduced the compressive strength by 47.8% and 62.4% for Mix 5A and 8A respectively. The compressive strength was reduced by 62.4% and 68.8% for Mix 5B and 8B respectively It is also worth mentioning that the concrete texture and colour changed by increasing the fly ash content.
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As can be seen in the examples in the table above, compressive strength bears little influence on refractoriness. Looking at examples where refractories include coal dust- such as many fire bricks, it has been stated that thermal conductivity decreases with increases in compressive strength and pore size (i.e. more porous)(5H).
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Point load testing is used to determine rock strength indexes in geotechnical practice. The point load test apparatus and procedure enables economical testing of core or lump rock samples in either a field or laboratory setting. In order to estimate uniaxial compressive strength, index-to-strength conversion factors are used. These factors have been proposed by various researchers and are ...
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The amount of organic binder used in coal briquetting is more sensitive than the inorganic binder in terms of briquette cold compressive strength. Inorganic binder can significantly increase the strength of briquette, but it will increase the briquette ash and the cohesiveness is not high.
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The compressive strength values were compared to M 25 grade of conventional concrete (CC). From the results, it is observed that the increase in CWR replacement level decreased the compressive strength. ... {COMPRESSIVE STRENGTH OF CONCRETE MADE WITH COAL WASHERY REJECTS AS COARSE AGGREGATE}, author={R. Rajesh Kumar and Kumari Shalini and J ...
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Figure 1: Compressive strength results of coal bottom ash (CBA) geopolymers according to each duration of 75 °C oven curing and 700 W microwave irradiation. 216. TechConnect Briefs 2018, TechConnect, ISBN 978-0-9988782-3-2. The bond structure and characteristics were analyzed by
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The S30 group had the highest 90 d compressive strength of 59.3 MPa in the coal gangue concrete, which is 11.5% higher than the 90 d compressive strength of the OPC. Figure 2 Compressive strength of ( a) 28 d, 90 d and ( b) 28 d-90 d growth rate. The strength reduction rate was derived from Figure 2 b.
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MTS815 servo-control testing machine was used for measuring the mechanical parameters of compressive strength of coal samples in an equal-displacement manner at a rate of 0.1 mm/min. Fig. 6 shows the uniaxial compression experimental system of coal samples. Fig. 7 shows the damage in some coal samples.
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The compressive strength have been measured on irregular shaped coals ranging from 0.1mm to 2.0mm particle size for low ash coals in Hokkaido. The results obtained from these experiments and those obtained from the silica ball-mill grinding test for the same coals are summerized as follows: ... For coals showing high H. I. as Naie coal, the ...
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This index can be used to estimate other rock strength parameters. The focus of this paper is to present the data analysis used to correlate the point load test index (Is50) with the uniaxial compressive strength (UCS), and to propose appropriate Is50 to UCS conversion factors for different coal measure rocks. The rock strength determined by ...
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Download scientific diagram | Compressive strength (CS) loss and weight loss (CS %) of FPC in seawater solution. from publication: Durability and Water Absorption Properties of Fly Ash based ...
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The Calorific Value of Wet Powdered Coal Transmittance 0.00 Absorbance 1.51 Mass of powdered coal 413.8g Volume of powered coal 500ml Volume of oil 100ml III. WET COMPRESSIVE STRENGTH TEST Compressive strength is the capacity of a material to withstand axially directed pushing forces.
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The 90 d chloride ion corrosion compressive strength with coal gangue content decreased first, and then increased, and increased when the coal gangue content was 100%. The ACSC showed the best chloride penetration resistance under 30% uncalcined coal gangue content, which was less than 27.75% lower than that of using OPC. ...
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In situ micropillar compression studies inside a scanning electron microscope show that CoAl intermetallic with Co-rich thick GBs has an ultrahigh yield strength of ~4.5 GPa and sustains prominent work hardening to a flow stress of ~5.7 GPa, one of the highest reported to date among B2 intermetallics.
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Oct 1, 2020The highest compressive strength (29.5 MPa) was shown by a sample with GNs of 20 mg/mL and a curing temperature of 8°C. Meanwhile, geopolymer without GNs showed the lowest compressive strength in all curing temperatures. Proximate analysis showed that fly ash used in this work was the high calcium of type-C fly ash with the CaO content of 11.18%.
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With the increase of moisture content in the range from 1.01% to 6.29%, following conclusions are obtained: 1) uniaxial compressive strength and elastic modulus of coal samples decrease gradually; 2) peak strain and maximum axial strain firstly increase and then reach stable at moisture content 4% and 5% respectively; 3) when shear angles are ...
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To facilitate the practical application of fiber-reinforced polymer (FRP) strengthened structures and improve the bearing capacity and deformation capacity of coal pillar in goaf, the mechanical performance of carbon fiber-reinforced polymer (CFRP) uniformly wrapped coal columns under axial compression was explored. Test results show that its state is basically unchanged and the fracture ...
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The hardness of Coal is 1-1.5 whereas its compressive strength is Not Available. Streak is the color of rock when it is crushed or powdered. The streak of Coal is black whereas its fracture is conchoidal. Luster of Coal is the interaction of light with the surface of Coal. Luster of Coal is dull to vitreous to submetallic.
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Our experiment validated the feasibility of utilizing coal gangue as coarse aggregate for concrete, with a maximum substitution amount determined by the concrete's designed strength and environmental factors. The existence of the cavities at the bond between the coal gangue and the cementing material inhibits compressive strength and ...
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Dynamic compressive strength of combined coal-rock body increases significantly with increasing confining pressure at low strain rate, but it increases more smoothly at higher strain rate. The...
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The replacement level of coal gangue in the cement should not exceed 20% by weight. The active SiO 2 and Al 2 O 3 in the thermal-activated coal gangue are able to react with the Ca (OH) 2, which was produced by cement hydration, and form hydrated calcium silicate and hydrated calcium aluminate gel to enhance the compressive strength of cement.
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