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"A baby is born with a need to be loved - and never outgrows it."
-Frank Howard Clark

"A hug is like a boomerang - you get it back right away."
-Bil Keane

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-Ingrid Bergman

"All love shifts and changes. I don't know if you can be wholeheartedly in love all the time."
-Julie Andrews

"Being deeply loved by someone gives you strength, while loving someone deeply gives you courage."
-Lao Tzu

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-Richard Bach

"Love consists in this, that two solitudes protect and touch and greet each other."
-Rainer Maria Rilke

Tuesday, October 16, 2007
Petrography is the description and classification of rocks by means of microscopic examination. With an accurate description of the mineralogy, a prediction of its chemical, The physical and mechanical performance in service can be made. Depending on the application, other methods should also be used in conjunction with petrography.

check 2: Water Absorption, Porosity & Density
Water absorption is the proportion of water able to be absorbed by stone under specific immersion conditions. The value obtained, together with its porosity and density provides symdoms and some indication of the stone’s performance in service, particularly its strong and strength, durability and stain resistance.

check 3: Flexural Strength
The flexural strength of the stone is critical in both the design and detailing of building facades, and also for use as a flooring material. Flexural strength is a measure of the tensile strength of tiles when subjected to bending. The test can be used to determine whether a wall or floor tile will crack or fracture under externally induced stress conditions.

check4: Impact Resistance
The impact resistance of stone indicates its ability to withstand cracking, indentations in the surface or surface chipping due to heavy blows, such as those caused by objects being dropped down, or the impact of shopping trolley wheels at tile edges. It is assessed by measuring the coefficient of restitution (COR)

check5: Scratch Hardness
Some stones are very soft and should not be used in areas of high traffic, unless appropriate measures are taken. Tiles with low scratch resistance will require higher levels of maintenance. Scratch hardness of tiles is determined by drawing certain minerals of defined hardness by hand over the test surface.

check6: Abrasion Resistance
Abrasion resistance represents the resistance of the stone’s surface to wear, usually caused by pedestrian traffic of tiles, the wheels of trolleys and the legs of furniture. Stone tiles that are installed in high traffic areas should be tested for both abrasion and impact resistance. If the tiles are to be sealed in service, they should be tested in that state.

check7: Thermal Expansion
In this method, a dilatometer is used to determine the linear thermal expansion coefficient of tiles in the temperature range from ambient to 100ºC. Such test results are particularly useful where tiles are to be installed in conditions that are exposed to large temperature differences.

check8: Thermal Shock
Thermal shock may occur when hot or cold substances come into contact with the tiles (e.g. boiling liquid, steam, hot saucepans, unexpected changes in air temperature). Thermal shock resistance of tiles is the characteristic which indicates whether the tile is capable of withstanding several rapid changes in temperature without being damaged.

check9: Dimensional Stability
The measurement of permanent (irreversible) expansion, shrinkage of tiles and/or distortion caused by moisture and/or temperature changes. This method determines the dimensional stability of stone tiles by measuring:

check 10: Frost Resistance
When water freezes inside pores, its increased volume may subject the stone of tiles to considerable mechanical stress leading to cracking, chipping and sometimes delamination of the stone tile.

check11: Chemical Resistance
Calcareous stones (e.g. limestones, marbles, calcareous sandstones) are susceptible to attack by acidic solutions (e.g. acid rain, some cleaning products, citric juices). Some stones are also susceptible to alkaline solutions of tiles (e.g. some alkaline cleaners can penetrate porous stones, dry out, and possibly cause the stone to fret).

check 12: Acid Immersion Test
The test, in conjunction with other tests (e.g. water absorption, thermal expansion of tiles, flexural strength), is useful for assessing the durability of stone subjected to areas of high atmospheric pollution in some urban and industrial environments.

check 13: Stain Resistance
The principle of this test is to subject specimens to various staining of tiles reagents for 24 hours; the surface is then inspected for visible changes, and again as it is subjected to a series of cleaning methods. The test uses three groups of staining reagents: stains having tracing action (pastes), chemical/oxidising action, and filming action.

check14: Weatherability
If there is no recognisable track record of the particular stone, one can use an artificial accelerated weathering of tiles procedure. At CSIRO we have developed a weather-o-meter that simulates weathering processes by using alternate cycles of high temperatures

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posted by jokash @ 8:33 AM  
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