scholarly journals The Impact of Secondary Phyllosilicate Minerals on the Engineering Properties of Various Igneous Aggregates from Greece

Minerals ◽  
2018 ◽  
Vol 8 (8) ◽  
pp. 329 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Eleni Koutsopoulou ◽  
...  
Keyword(s):  
Regression Analysis ◽  
Los Angeles ◽  
Moisture Content ◽  
Total Porosity ◽  
Physicomechanical Properties ◽  
Engineering Properties ◽  
Petrographic Analysis ◽  
Rock Samples ◽  
Los Angeles Abrasion ◽  
The Impact

This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks used as aggregates, from various areas from Greece. The studied lithologies include serpentinized dunites, serpentinized harzburgites, serpentinized lherzolites, metamorphic gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of the studied rock samples was performed by using the Rietveld method on X-ray diffraction patterns. The samples were also tested to assign moisture content (w (%)), total porosity (nt (%)), uniaxial compressive strength (UCS (MPa)) and Los Angeles abrasion test (LA (%)). The influence of secondary phyllosilicate minerals on the physicomechanical behavior of the tested samples was determined using regression analysis and their derived equations. Regression analysis shows a positive relationship between the percentage of the phyllosilicate minerals of the rocks and the moisture content as well as with the total porosity values. In mafic and ultramafic rock samples, the relationships between the secondary phyllosilicate minerals and their physicomechanical properties have shown that the total amount of the secondary phyllosilicate minerals results negatively on their physicomechanical properties. On the other hand, the low percentage of phyllosilicate minerals in volcanic rocks can’t be able to define their engineering properties.

scholarly journals The Impact of Secondary Phyllosilicate Minerals on the Engineering Properties of Various Igneous Aggregates from Greece

2018 ◽  
Author(s):  
Petros Petrounias ◽  
Panagiota P. Giannakopoulou ◽  
Aikaterini Rogkala ◽  
Paraskevi Lampropoulou ◽  
Eleni Koutsopoulou ◽  
...  
Keyword(s):  
Mechanical Properties ◽  
Regression Analysis ◽  
Los Angeles ◽  
Moisture Content ◽  
Rietveld Method ◽  
Total Porosity ◽  
Engineering Properties ◽  
Petrographic Analysis ◽  
Los Angeles Abrasion ◽  
The Impact

This paper investigates the effect of alteration on the physicomechanical properties of igneous rocks from various areas from Greece used as aggregates. The studied lithologies include dunites, harzburgites, lherzolites, gabbros, diabases, dacites and andesites. Quantitative petrographic analysis shows that the tested samples display various percentages of secondary phyllosilicate minerals. Mineral quantification of studied rock samples was performed by using a Rietveld method on X-Ray diffraction patterns of the studied aggregates. The aggregates are also tested to assign moisture content [w (%)], total porosity [nt (%)], uniaxial compressive strength [UCS (MPa)] and Los Angeles abrasion test [LA (%)]. The influence of secondary phyllosilicate minerals on physicomechanical behavior of tested samples determined using regression analysis and their derived equations. Regression analysis shows positive relationship between the percentage of phyllosilicate minerals of rocks and moisture content as well as with the total porosity values. The relationships between phyllosilicate minerals in the ultramafic and mafic samples and their mechanical properties show that the total rates of phyllosilicate mineral products result negatively in their mechanical properties, while the low percentage of phyllosilicate minerals in volcanic rocks are not able to define set of their engineering parameters.

scholarly journals Review of the relationship between aggregates geology and Los Angeles and micro-Deval tests

2021 ◽  
Vol 80 (3) ◽  
pp. 1963-1980
Author(s):  
Solomon Adomako ◽  
Christian John Engelsen ◽  
Rein Terje Thorstensen ◽  
Diego Maria Barbieri
Keyword(s):  
Los Angeles ◽  
Crystal Size ◽  
Grain Shape ◽  
Mechanical Performance ◽  
Pore Space ◽  
Construction Material ◽  
Engineering Properties ◽  
Coarse Grained ◽  
The Impact ◽  
The Relationship

AbstractRock aggregates constitute the enormous volume of inert construction material used around the globe. The petrologic description as igneous, sedimentary, and metamorphic types establishes the intrinsic formation pattern of the parent rock. The engineering properties of these rocks vary due to the differences in the transformation process (e.g. hydrothermal deposits) and weathering effect. The two most common mechanical tests used to investigate the performance of aggregates are the Los Angeles (LA) and micro-Deval (MD) tests. This study reviewed the geological parameters (including mineralogy, grain and crystal size, grain shape, and porosity) and the relationship to Los Angeles and micro-Deval tests. It was found that high content of primary minerals in rocks (e.g. quartz and feldspar) is a significant parameter for performance evaluation. Traces of secondary and accessory minerals also affect the performance of rocks, although in many cases it is based on the percentage. Furthermore, some studies showed that the effect of mineralogic composition on mechanical strength is not sufficient to draw final conclusions of mechanical performance; therefore, the impact of other textural characteristics should be considered. The disposition of grain size and crystal size (e.g. as result of lithification) showed that rocks composed of fine-grain textural composition of ≤ 1 mm enhanced fragmentation and wear resistance than medium and coarse grained (≥ 1 mm). The effect of grain shape was based on convex and concave shapes and flat and elongated apexes of tested samples. The equidimensional form descriptor of rocks somehow improved resistance to impact from LA than highly flat and elongated particles. Lastly, the distribution of pore space investigated by means of the saturation method mostly showed moderate (R = 0.50) to strong (R = 0.90) and positive correlations to LA and MD tests.

NOISE LEVEL MEASUREMENT TEST TO PREDICT THE ABRASION RESISTANCE OF ROCK AGGREGATES

2013 ◽  
Vol 12 (04) ◽  
pp. 1350021 ◽  
Author(s):  
S. KAHRAMAN ◽  
M. S. DELIBALTA ◽  
R. COMAKLI
Keyword(s):  
Regression Analysis ◽  
Los Angeles ◽  
Multiple Regression Analysis ◽  
Multiple Regression ◽  
Noise Level ◽  
Regression Equation ◽  
Abrasion Loss ◽  
Los Angeles Abrasion ◽  
Indirect Tests ◽  
Simple Regression

Compared to the indirect tests, the determination of the Los Angeles abrasion loss is time consuming and expensive, and requires a large amount of samples. For this reason, the prediction of Los Angeles abrasion loss from some indirect tests is useful for preliminary studies. In this study, Los Angeles abrasion, noise level (NL) measurement, density, and porosity tests were carried out on 27 different rock types such as igneous, metamorphic, and sedimentary. The test results were evaluated using the simple and multiple regression analysis. A good relation was found between the Los Angeles abrasion loss and the NL. In order to check the possibility of obtaining more significant relations, multiple regression analysis was performed by including density and porosity values. However, the regression analysis showed that the correlation coefficients of the multiple regression equations were slightly higher than that of the simple regression equation. Since the simple regression equation is practical and statistically significant, it is suggested for estimation purpose. In conclusion, it can be said that Los Angeles abrasion loss of aggregates can be reliably estimated from NL measurement.

Dew Point of the Flue Gas of Boilers Co-Firing Biomass with Coal

2013 ◽  
Vol 34 (1) ◽  
pp. 101-108 ◽  
Author(s):  
Szymon Ciukaj ◽  
Marek Pronobis
Keyword(s):  
Regression Analysis ◽  
Moisture Content ◽  
Flue Gas ◽  
Large Scale ◽  
Fuel Mixture ◽  
Dew Point ◽  
Outlet Temperature ◽  
Utility Boilers ◽  
Boiler Efficiency ◽  
The Impact

Abstract The paper deals with the impact of co-firing biomass with coal in boilers on the dew point of the flue gas. Co-firing of biomass may have twofold implications on corrosion and fouling, which are the processes that determine the lowest acceptable flue gas outlet temperature and as a result, boiler efficiency. Both phenomena may be reduced by co-firing of usually low sulphur biomasses or enhanced due to increased moisture content of biomass leading to increased water dew point. The present study concerns the problem of low-temperature corrosion in utility boilers. The paper gives (in the form of diagrams and equations) a relationship between water dew point and moisture content of fuel mixture when co-firing coal and various biomasses. The regression analysis shows that despite significant differences in the characteristics of coals and these of additional fuels, which are planned for co-firing in large-scale power boilers, the water dew point can be described by a function given with the accuracy, which shall be satisfactory for engineering purposes. The discussion of the properties of biofuels indicates that the acid dew point surplus over the water dew point (Δtr = tr - twr) is not likely to exceed 10 K when co-firing biomass. The concluding remarks give recommendations for the appropriate operation of boilers in order to reduce risks associated with biomass co-combustion.

Aggregate Polishing Resistance Pre-Evaluation

1996 ◽  
Vol 1530 (1) ◽  
pp. 103-110
Author(s):  
L. K. Crouch ◽  
Greg Shirley ◽  
Gary Head ◽  
William A. Goodwin
Keyword(s):  
Los Angeles ◽  
Coefficient Of Variation ◽  
Frictional Resistance ◽  
Test Method ◽  
Engineering Properties ◽  
Los Angeles Abrasion ◽  
Maximum Coefficient ◽  
Resistance Performance ◽  
Single Size ◽  
Repeatability Test

Current methods of pre-evaluation of aggregates for bituminous surface courses such as the British Pendulum and British Polishing Wheel and chemical or mineralogical methods are only able to identify clearly aggregates with a high probability of performing well. There is little agreement among researchers as to what engineering properties will provide adequate frictional resistance at various average daily traffic (ADT) levels. The lack of agreement has led to conservative polish-resistance specifications and subsequently higher pavement costs. The Tennessee Textural Retention Method (TTRM) uses single size aggregate (6.35 to 9.52 mm), the Los Angeles Abrasion device, and a modified version of the AASHTO TP 33 device to evaluate particle shape and texture throughout simulated aging. In this evaluation, using 25 Tennessee aggregates, the TTRM was used to characterize aggregate polish-resistance performance at various ADT levels by comparing the results obtained on other aggregates with the results from field proven performers. The TTRM ranked all Tennessee proven performing siliceous limestones and gravels in the appropriate ADT category for which they are currently approved. In addition, new promising aggregate sources were revealed. The test method had a coefficient of variation for aggregate ratings of less than 3 percent for a nine-sample repeatability test. In addition, the maximum coefficient of variation of voids tests at any given aging revolution for an individual aggregate never exceeded 2 percent. The method may be helpful in pairing aggregate polish-resistance performance with pavement need based on ADT.

scholarly journals Evaluation of the viability of recycling railroad ballast for reusing in railroads

2021 ◽  
Vol 10 (13) ◽  
pp. e277101321231
Author(s):  
Jhenifer Terezinha Aparecida Mattos Cescon ◽  
Ben-Hur de Albuquerque e Silva ◽  
Maria Esther Soares Marques ◽  
Romero Pereira dos Santos
Keyword(s):  
Los Angeles ◽  
Laboratory Tests ◽  
Strength Properties ◽  
Rock Composition ◽  
Los Angeles Abrasion ◽  
Mineralogical Characteristics ◽  
The World ◽  
Original Rock ◽  
The Impact

The main objective of this study is to assess the reuse of naturally old ballast that was removed from an operating railroad.  In order to verify the viability of its reuse, laboratory tests were carried out, based on the procedures and parameters established in literature. The reuse of ballast would reduce costs, minimize the disposal of this material and reduce quarry extraction. There are several standards regulations the ballast’s (gravel) properties, such as size, shape, hardness, abrasion resistance and composition to provide better performance of the rail platform, due to the wide variety of materials and environmental conditions to which they are subjected. Ballast specifications are based on the execution of characterization tests and can be divided according to strength properties and geometric properties. Thus, several specifications have been used by different railway organizations around the world to meet the needs of their projects. One test used to analyze ballast quality is the Los Angeles Abrasion, which provides data on resistance to fragmentation. The durability of the ballast depends on the quality of the gravel related to the original rock composition. This is an important parameter that can be associated with railroad maintenance, which is expensive. A series of tests were carried out to evaluate the ballast properties, as well as an analysis of the geometric and mineralogical characteristics of the gravel, and the impact of the variation of these properties in the performance of the ballast. The viability of reusing the ballast removed from an operating road was then evaluated, and it was concluded that the material is still suitable for reusing, although its properties have undergone a few changes, without modifying its main characteristics and functions.

scholarly journals RELATIONSHIPS BETWEEN PETROGRAPHIC AND PHYSICOMECHANICAL PROPERTIES OF BASIC IGNEOUS ROCKS FROM THE PINDOS OPHIOLITIC COMPLEX, NW GREECE

2007 ◽  
Vol 40 (2) ◽  
pp. 947 ◽  
Author(s):  
P. Pomonis ◽  
I. Rigopoulos ◽  
B. Tsikouras ◽  
K. Hatzipanagiotou
Keyword(s):  
Los Angeles ◽  
Total Porosity ◽  
Mineralogical Composition ◽  
Physicomechanical Properties ◽  
Igneous Rocks ◽  
Point Count ◽  
Rock Types ◽  
Point Count Method ◽  
Northwestern Greece ◽  
Ophiolitic Complex

The relationships between pétrographie and physicomechanical properties of basic igneous rocks· from the Pindos ophiolitic complex, northwestern Greece, were investigated. The mineralogical composition was quantified from one polished thin section per sample with a polarizing microscope, by using the point count method. Textural description was also carried out by using both polarizing and scanning electron microscope. The same samples were also tested to determine moisture content, water absorption, specific gravity, total porosity, void ratio, uniaxial compressive strength, Los Angeles, micro-Deval, PSV and Sand Equivalent values. The relationships between these properties and the pétrographie characteristics are described by simple regression analyses. The results indicate that plagioclase, chlorite, quartz and actinolite contents of the studied rock-types significantly influence their physicomechanical properties. Additionally, some textural parameters such as the mean grain size and the complexity of grain boundaries influence their mechanical strength.

scholarly journals Experimental Investigation of Mechanical Behavior of Sandstone with Different Moisture Contents Using the Acoustic Emission Technique

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Chuanming Li ◽  
Nan Liu ◽  
Wanrong Liu
Keyword(s):  
Tensile Strength ◽  
Compressive Strength ◽  
Moisture Content ◽  
Physicomechanical Properties ◽  
Underground Engineering ◽  
Softening Effect ◽  
Engineering Construction ◽  
Rock Samples ◽  
Saturated Rock ◽  
Water Saturated

The moisture content is a critical factor tightly related to rock deformation and its failure process since it leads to a significant change in the physicomechanical properties of rock during the underground engineering construction. As a result, engineering construction accidents take place frequently. To figure out the influence of the moisture content on the physicomechanical properties of water-bearing rock and then effectively avoid engineering accidents, multiple tests including the uniaxial compression test, Brazilian splitting test, and the acoustic emission (AE) test were carried out in this study. The experimental results showed that the water absorption rate of the sandstone gradually stabilizes after 5 h, and its uniaxial compressive strength, tensile strength, and elastic modulus all decline with the increase of the moisture content. Compared to the dry state of the sample, the reduction amplitudes of the elastic modulus, compressive strength, and tensile strength of water-saturated rock samples can reach up to 27.3%, 35.2%, and 38.1%, respectively. It indicates that the tensile strength is more sensitive to the softening effect of the moisture. Through the AE test, it can be found that the internal state of water-saturated rock samples is greatly changed; the compressive strength of rock samples drops, so the rock can be damaged after absorbing less energy. Thus, moisture shows a certain softening effect on rock. The research results are expected to provide a basis for underground engineering construction and rock fracture and failure.

scholarly journals Petrography and Physicomechanical Characteristics of Iyuku Granite, Southwestern Nigeria

2020 ◽  
pp. 2926-2935
Author(s):  
Felix Chukwuka Ugbe
Keyword(s):  
Los Angeles ◽  
Water Absorption ◽  
Road Construction ◽  
Mechanical Tests ◽  
Petrographic Analysis ◽  
Quartz Content ◽  
Southwestern Nigeria ◽  
Physicomechanical Characteristics ◽  
Statistical Correlations ◽  
Los Angeles Abrasion

Petrography and physicomechanical characteristics of Iyuku granite from southwestern Nigeria were investigated. Rock and aggregate samples were obtained from five different quarry sites for thin-sectioning and physical and mechanical tests. The rock slides were subjected to petrographic analysis, while the aggregates were tested for the parameters of specific gravity (S.G), water absorption, aggregate impact value (AIV), aggregate crushing value (ACV), Los Angeles abrasion value (LAAV), and flakiness and elongation indices in accordance with the British Standards (B.S), American Standards for Testing Materials (ASTM) and Federal Ministry of Works Standards (FMWS). The petrographic, physical, and mechanical characteristics were described by bar charts and linear graphs. The results revealed that the rocks are of medium to coarse interlocking grains, with no evidence of weathering influences, and quartz content ranging from 17% to 35%. The aggregates showed appreciable high S.G. values, very low water absorption values and low maximum permission limits for AIV, ACV and LAAV when compared with different standards. All the aggregates are adjudged to be generally strong and durable for road construction, but those with higher quartz contents are more preferable. Significant statistical correlations were established among both physical and mechanical tests conducted.

Experimental Research and Regression Analysis for Constant Temperature Drying of Wheat Straw

2011 ◽  
Vol 194-196 ◽  
pp. 1442-1448
Author(s):  
Jian Jun Hu ◽  
Quan Guo Zhang ◽  
Hao Huang
Keyword(s):  
Regression Analysis ◽  
Moisture Content ◽  
Wheat Straw ◽  
Constant Temperature ◽  
Initial Moisture Content ◽  
Regression Equations ◽  
Drying Time ◽  
Drying Temperature ◽  
Drying Section ◽  
The Impact

The constant temperature drying experiment on wheat straw at different initial moisture content and drying temperature were made with comprehensive thermal analyzer. The impact of initial moisture content, drying temperature and drying time on wheat straw procedure were reviewed, and the optimum drying result of wheat straw were gotten when initial moisture content was 32.5% and drying temperature was 100°C .The process of wheat straw drying was divided into three sections about preheating, constant temperature and falling rate drying. Regression equations on different sections were established by regression analysis, the result show that parabolic equation in preheating section, linear equation in constant rate drying section and power curve in falling rate drying section. Experiment data and reference frame from conclusion above were useful to crop straw drying technology.

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