types,manufacturing and behaviour of dimension or decorative stone

DIMENSION STONE

Definition:Dimension stones are naturally occurring rocks of igneous, metamorphic and sedimentary origin which are sufficiently consolidated to enable them to be cut or shaped into blocks or slabs for use as wailing, paving and roofing material in the construction of building and other structures.

Rock Types:Principally limestone (including marbles), sandstone, slates and granite are used as dimension stone.

Texture, Minerology and Colour:

Dimension Stone shows a wide variety of texture and minerology depending on their origin. Colour is an important aspect but does not follow agreed and standard colour scheme.

Types:I. Igneous Dimension Stone.

II. Sedimentary Dimension Stone.

III. Metamorphic Dimension Stone.

IV. Miscellaneous Dimension Stone.

Igneous Dimension Stone: These are hard and crystalline and widely used as dimension stones

but commonly termed as granite by trade. Igneous rocks show a range from pale coloured, coarsely

crystalline, quartzo feldspathic varieties to dark coloured, fine grained, basaltic rock type.

Sedimentary Dimension Stone: Sedimentary rocks include our most common dimension stones.

Sandstone and Limestone are most common in them. These are formed by cementing of pre-existing igneous rocks and

high quartz content in them makes them hard and durable building stone.

An important feature of sedimentary rocks is their natural porosity which makes them more durable dimension stone because intergrannular pore spaces facilitate easier dressing and shaping of stone.

Metamorphic Dimension Stone: These are not widely used commercially as dimension stone but are

fine grained. Cleaved slates are the principal source of roofing stone worldwide. Included in the metamorphic rocks are the true marbles.

Miscellaneous Dimension Stone: Some texturally and minerologically distinctive rocks are used for

decorative building purposes include ironstone, flint, tufa, etc.

Extraction Method and Processing: Quarrying and Mining: The open part of the natural rock from which useful stone is

obtained is known as quarry. Dimension stone quarried or mined without use of blasting

techniques, which could have serious detrimental effects on the structure of the softer stone varieties.

The quarry face initially opened up by exploiting naturally occurring lines of weakness in rocks like joints, bedding planes, etc.

Underground working take place at relatively shallow depths by adits or augers.

Stone production depends on room and pillar method of extraction.

Stone Processing:

Processing of stone is begins at the quarry or following transportation to centralized cutting sheds depending on the requirement of the contract.

Softer stones such as limestone can be shaped and dressed using hand or cut using hand saws.

Harder stones may need to be sawn using frame saws, gang saws, diamond rotary blades, high pressure water jets, etc.

Surface finishing of some stones can involve polishing using abrasive and flamejet texturing.

Methods of stone exploitation from the past to present

Classification and Uses Building stone trade applies following broad specifications: Building Stone: Natural rock material quarried or extracted for

obtaining blocks and slabs that can shaped and sawn for general building.

Stone Cladding: Natural rock material quarried, sawn and polished for non load bearing walling material.

Non-load-bearing walls: are those that carry only their own weight. Walling Stone: Natural rock material quarried for non dressed (rubble) blocks.

Rubble: Waste or rough fragments of stone, brick, concrete, etc.

Flagstone: Natural rock material quarried, sawn and split specially for flooring and paving.

Stone slates: Natural rock material (other than slates) that is thinly bedded and fissile (easily split into slabs).

Rockery Stone: Natural Stone cobbles and boulders of varied lithological composition used in landscaping and gardening.

Monumental Stone: Natural rock material quarried, cut, split, dressed or polished specially for use in monuments, gravestones, or memorial tables.

Decorative Stone: Natural rock material quarried, sawn, worked and polished for (architectural) ornamentation.

Marble: Geologist use this term to limestone that is alter by metamorphism, however the building trade uses this term to cover any limestone that is hard enough to produce a polished surface.

Different uses of stones and their proportion (modified after Hoffmann 2007)

RECOMMENDED TEST METHODS:

Test for Water Penetration using dynamic pressure. Air Infiltration Test by static pressure. Structural Load Test by uniform static pressure (positive and

negative). Water Infiltration Test by static pressure

FINISHES

Sedimentary stones: Smooth (machine finished by saw, grinder, or planer). Machine tooled (uniform grooves). Chat Sawn (non-uniform, shallow saw marks). Shot sawn (irregular and uneven markings). Split face (concave - convex). Rock face (convex). Natural cleft.

Metamorphic stones: Sanded Honed (medium to high honed) Polished Wheel abraded Bush-hammered Split Face Rock Face Natural cleft

Igneous Stones: Sawn Honed Polished Machine tooled (4-cut, 6-cut, chiseled, axed, pointed, etc.) Flamed Sandblasted Split Face Rock face

Uses

Foundation and Wall Items: Quarry, split and sawn stones from rocks are used to erect the

substructure of buildings. Piece stones sawn and split from limestone, sandstone, dolomite and

volcanic tuff are used for walls, piers, abutments, etc. Facing and Architectural Items: Facing slabs and stones, stairs and landings, parapets, etc. are made

of slabs sawn or split. Facing slabs of granite, gabbro, basalt, marble, breccia, limestone,

sandstone and volcanic tuff are generally used

Architectural and historical uses of stones:(a) Megalithic temples of Malta (app. 2500–3200 years BP)(b) Pyramids of Giza(c) The Acropolis (Athens)(d) Forum Romanum(Rome)

Building Items: Elements of stairs, landings, parapets and guard rails are

manufactured from granite, marble, limestone, tuff, etc.

Road Construction Items: Curb stones—intended to separate roadways from sidewalks Paving blocks—used for pavements. Cobble stone—used to reinforce slopes of earth works and banks of

water basins

Underground Structures and Bridges: These are built of slabs and stones from igneous and sedimentary

rocks. Tunnels and above-water elements of bridges are built of granite,

diorite, gabbro and basalt. Heat and Chemically resistant items: These are manufactured from non-weathered rocks. For high temperature working conditions, they are made from

chromite, basalt, andesite and tuffs.

Various uses of stones

Characteristics of Good Building Stone

Appearance: For face work it should have fine, compact texture; light-coloured

stone is preferred as dark colours are likely to fade out in due course of time.

Structure: A broken stone should not be dull in appearance and should have

uniform texture. Free from cavities, cracks, and patches of loose or soft material.

Stratifications should not be visible to naked eye.

Strength: A stone should be strong and durable to withstand the disintegrating

action of weather. Compressive strength of building stones in practice range between

60 to 200 N/mm2. Weight: It is an indication of the porosity and density. For stability of structures such as dams, retaining walls, etc. heavier

stones are required. For arches, vaults, domes, etc. light stones may be the choice.

Hardness: This property is important for floors, pavements, aprons of bridges,

etc. The hardness is determined by various tests in lab. specially Loss

Angeles Test. Toughness: The measure of impact that a stone can withstand is defined as

toughness. The stone used should be tough when vibratory or moving loads are

anticipated.

Porosity and Absorption: Porosity depends on the mineral constituents, cooling time and

structural formation. A porous stone disintegrates as the absorbed rain water freezes,

expands, and causes cracking. Seasoning: The stone should be well seasoned. Weathering: The resistance of stone against the wear and tear due to natural

agencies should be high.

Why We Build With Stones

Natural Stone Fascinates: Natural stone is a natural product whose individual properties are

determined by the type and bonding of the minerals comprising the natural stone.

Natural Stone Is Ecological: Natural stone as a building material is found in nature in a virtually

finished form. No energy is needed for its actual manufacture. Energy is only consumed for quarrying and processing

Natural Stone Is Environmentally Compatible: As natural building material, natural stone contains no pollutants

that are damaging to health. Natural stone can be safely used in food areas.

Natural Stone Is Varied: No other building material has as many different colors and

structures as natural stone. Various surface finishing processes make variety just about unlimited.

Natural Stone Ages Well: The lifetime of natural stone is extremely long. With the right

planning and construction, buildings of natural stone have been known to survive for many thousands of years.

Natural Stone Is Attractively Priced: If the total cost of a building material is considered over a useful life

of 30 years or more, independent investigators show that natural stone is no more expensive than comparable synthetic building materials.

Natural Stone Is Durable: The high-pressure resistance values of many natural stones have

given the material a reputation of being an everlasting material. Natural stone is also the most durable material with the lowest abrasion values for floor coverings

Production Of Building Stones

The percentage of stone production with respect to continents in a more general overview (after Montani 2005)

Leading nations in the production of dimension stones and the amount of stone produced in millions of tons (after Montani 2008)

Occurrence of stones in the field.

References

Building Materials (Third Revised Edition) By S.K. Duggal. Building and Roofing Stone By British Geological Survey. Building Stone Institute (American Architectural Manufacturers

Association (AAMA). Building Stones By Siegfried Siegesmund and Ákos Török