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Estimating Some Mechanical Properties Of Rock From In-situ Rebound Values
[A CASE STUDY OF OREKE OPEN PIT QUARRY]
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As metamorphism progresses, the crystals grow larger and become easily
recognizable as interlocking crystals of calcite. Recrystallisatoin
obscures the original fossils and sedimentary structures of the
limestone. It also occurs without forming foliation, which normally is
found in rocks that are altered by the directed pressure of a convergent
plate boundary.
Recrystallisation is what marks the
separation between limestone and marble. Marble that has been exposed to
low levels of metamorphism will have very small calcite crystals. The
crystals become larger as the level of metamorphism progresses. Clay
minerals within the marble will alter to micas and more complex silicate
structures as the level of metamorphism increases. (Goodie, (1998).
Physical Properties and Uses of Marble
Marble occurs in large deposits that can be hundreds of feet thick and
geographically extensive. This allows it to be economically mined on a
large scale, with some mines and quarries producing millions of tons per
year.
Most marble is made into either crushed stone or dimension
stone. Crushed stone is used as an aggregate in highways, railroad
beds, building foundations, and other types of construction. Dimension
stone is produced by sawing marble into pieces of specific dimensions.
These are used in monuments, buildings, sculptures, paving and other
projects. We have an article about “the uses of marble†that includes
photos and descriptions of marble in many types of uses.
Colour:
marble is usually a light – coloured rock. When it is formed from a
limestone with very few impurities, it will be white in colour. Marble
that contains impurities such as clay minerals, iron oxides, or
bituminous material can be bluish, gray, pink, yellow, or black in
color.
Marble of extremely high purity with a bright white color
is very useful. It is often mined, crushed to a powder, and then
processed to remove as many impurities as possible. The resulting
product is called “whitingâ€. This powder is used as a colouring agent
and filler in paint, whitewash, putty, plastic, grout, cosmetics, paper
and other manufactured products.
Acid reaction: Being composed of
calcium carbonate, marble will react in contact with many acids,
neutralizing the acid. It is one of most effective acid neutralization
materials. Marble is often crushed and used for acid neutralization is
streams, lakes and soils.
It is used for acid neutralization in the
chemical industry as well pharmaceutical antacid medicines such as
“Turns†contain calcium carbonate, which is sometimes made from powdered
marble. These medicines are helpful to people who suffer from acid
reflux or acid indigestion. Powdered marble is used as inert filler in
other pills.
Hardness: Being composed of calcite, marble has a
hardness of three on the Mohs hardness scale. As a result, marble is
easy to carve, and that makes it useful for producing sculptures and
ornamental objects. The translucence of marble makes it especially
attractive for many types of sculptures. The low hardness and solubility
of marble allows it to be used as a calcium additive in animal feeds.
Calcium additives are especially important for dairy cows and egg
producing chickens. It is also used as a low-hardness abrasive for
scrubbing bathroom and kitchen fixtures.
Ability to accept a polish: After being sanded with progressively liner abrasives, marble can be polished to a high luster. This allows attractive pieces of marble to be cut, polished and used as floor tiles. Architectural panels 13 cing stone, window sills, stair treads, columns, and many other pieces of decorative stone.
2.3 MECHANICAL PROPERTIES OF MARBLE
In Mediterranean Sea area, there exist a number of historical constructions using marble stones. Those marble stone constructions suffered sometimes serious damage by historical fires in their long histories. However, there have been insufficient knowledge and lack of information on the mechanical characteristics of marble stones affected by high temperature caused by historical fires. Such fire damage might reduce seismic safety of those marble constructions, as seismic activity is high in Mediterranean sea area. As well as, it might cause serious issues to be solved for restoration of heritage marble structures.
Current study of mechanical properties of marble according to Harris (2014) described the mechanical materials properties of marble stones used for constructions of ancient Greek temples, affected by high temperature are caused by fire. 1-Jeating tests of marble stone samples were conducted to study their material behaviors affected by high temperature. In the tests, the temperature for heating varied from 2000C to 12000C with temperature interval of 2000C. Also, the duration of heating was 2 hours (constant temperature time) in consideration of historical fires. Ocular inspections of materials and measurement of weight were carried out. In addition, compression tests of the specimen were performed to evaluate mechanical properties affected by high temperature. These experimental results demonstrated that marble stones used for constructions of Greek temples are vulnerable to high temperature caused by fires. Damage by historical fires should be considered for restoration of Greek temples of marble stones (Suzuki and Yamada, (2014).
Harris (2014) reported that marble is a metamorphic rock composed of, commonly, calcite or dolomite, and the chemical formula for marble is CaCO3. The chemical equation of the reaction in pyrolysis CaCO3 is changed into CaO as CO2 evaporates. When this occurs, the weight of marble stones begins to decrease. Moreover, CaO absorbs moisture in the air, then it is changed into Ca(O11)2 while giving off the heat of reaction.
Harris in his experiment posited that when marble are affected by high temperature the mechanical characteristics shown would be as follows;
1. The strength of the specimens was not affected by heating at temperature lower than 3000C. The reduction of compressive strength began at around 4000C. Such reduction of strength was caused remarkably at over 65O0C. The strength of the specimen after heating 6500C was reduced by 60% of the un-heated one. The strength of the specimens heated at temperature over 8000C reached 0 and fractured.
2. The weight of the specimens began to decrease at around 6500C. This reduction of weight can be explained by thermal decomposition reaction of marble material. Note that heating temperature having caused such reduction of density was corresponding to the temperature of remarkable reduction of the compressive strength mentioned above.
3. Progressive deterioration phenomenon of the specimens heated by higher temperature than 6500C-7000C was found during cooling time in the air. This phenomenon can be explained by absorption of moisture in the air. This deterioration must cause reduction of mechanical properties.
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ABSRACT - [ Total Page(s): 1 ]ABSTRACTThe research deals with estimating some mechanical properties of rock from in-situ rebound value in Oreke open pit quarry ,N-Type Schmidt rebound hammer data were collected from Oreke open pit .the data were collected with the view to ascertain the suitability of Schmidt hammer for quick ,cheap and less cumber some estimation of the uniaxial compressive strength of marble .The data collection was strictly carried out by ASTM and suggested equation by different authors. UNIAXIAL COMPRES ... Continue reading---
LIST OF TABLES - [ Total Page(s): 1 ]LIST OF TABLESTABLES 4.1: Determination of Bulk Density for Location 4.2: Density Test Result for Location 4.3: Density Test Result for Location 4.4: Field Rebound Values 4.5: Standard Procedure of Bulk Density Determination 4.6: Standard for Uniaxial Compressive Strength (UCS) ... Continue reading---
LIST OF FIGURES - [ Total Page(s): 1 ]LIST OF FIGURESFIGURES 1: Details of an L type Schmidt hammer 2: Conversion Graph ... Continue reading---
TABLE OF CONTENTS - [ Total Page(s): 1 ]TABLE OF CONTENTSTITLE PAGE CERTIFICATION DEDICATION ACKNOWLEDGEMENT TABLE OF CONTENTS LIST OF TABLES LIST OF FIGURES CHAPTER ONE 1.0 INTRODUCTION 1.1 AIM AND OBJECTIVES 1.2 STATEMENT OF THE PROBLEM 1.3 SCOPE OF THE PROJECT 1.4 JUSTIFICATION OF THE PROJECT 1.5 LOCATION OF THE STUDY AREA CHAPTER TWO 2.0 LITERATURE REVIEW 2.1 CONCEPT OF SCHMIDT REBOUND HAMMER 2.2 GEOLOGICAL FORMATION OF MARBLE 2.3 MECHANICAL PROPERTIES OF MARBLE ... Continue reading---
CHAPTER ONE - [ Total Page(s): 1 ]CHAPTER ONE 1.0 INTRODUCTIONRock mechanics engineers design structures built in rock for various purposes, and therefore need to determine the properties and behavior of the rock. The UCS of rocks is one of the important input parameters used in rock engineering projects such as design of underground spaces, rock blasting, drilling, slope stability analysis, excavations and many other civil and mining operations. ISRM (1981) testing of this mechanical property in the laboratory is a si ... Continue reading---
CHAPTER THREE - [ Total Page(s): 2 ]CHAPTER THREE3.0 RESEARCH METHODOLOGY (DESK WORK)The research methodology is the general research strategy that outlines. The way in which research is to be undertaken and among other things, identifies the methods to be used in it. These methods, described in the methodology, define the means or mode of data collection or sometimes, how a specific result is to be calculated. Methodology also is the systematic theoretical analysis of the methods applied to a field of study.Therefore, the N ... Continue reading---
CHAPTER FOUR - [ Total Page(s): 7 ]The result obtained for the uniaxial compressive strength range from lowest value to the highest value which is 1.15×1040mpa respectively. Base on the standard present by Deere and Miller (1966) and ASTM (2001). The mean value obtain which is6.22×1040mpa made the marble to be classified as a rock with very low strength. 4.3 DISCUSSION The average rebound value was used trace the UCS with the corresponding bulk density in figure (4.1.1). The result shows that the uniaxial comp ... Continue reading---
CHAPTER FIVE - [ Total Page(s): 1 ]CHAPTER FIVE5.0 CONCLUSION AND RECOMMENDATION5.1 CONCLUSIONThe need to test rock in order to determine their physical and mechanical properties cannot be overemphasized .However , laboratory testing procedures and equipment may be required to do this for engineering project .Hence, the Schmidt rebound hammer (RN) has being used by many researchers to measure the strength and other engineering properties of rocks. This usually enables a quick and easy means of measurement. Marble be ... Continue reading---
REFRENCES - [ Total Page(s): 1 ]REFERENCESAggestalis, G, Alivazators, (2000) Correlating Uniaxial Compressive Strength with Schmidt Hammer Rebound Number, Journal of Bulleting Engineering Geology, Vol. 5,4, ppg 3 – 11.ASTM, (2001) Standard Method for Determination of Rock Hardness of Rebound Hammer Method, ASTM Stand 04.09(D5873-00).ASTM. D-5873(2005) Standard Test Method for Determination of Rock Hardness by Rebound Value Method.Aufmuth, E.R. (2002). A Systematic Determination of Engineering Criteria for Rocks. Journal ... Continue reading---
