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Stones - Introduction 9/18/2018
In hilly regions, stones are more freely available than clay bricks. They occur naturally and need not be manufactured and hence stone masonry becomes cheaper than brickwork. From early days, even before bricks were invented by the humans, stones were used to make dwellings. Old roads with heavy traffic were also paved with stones, Beautiful monuments were also built with stones. Stones were also used for ornamental works. 9/18/2018
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Stones - Introduction 9/18/2018
Stones are more permanent than any other natural materials like wood Most of the prehistoric monuments that are today are made of stones Stoned used for heavy engineering constructions like bridge piers, harbour walls, sea side walls And also for facing work, tall buildings, foundations of buildings (which are liable to be flooded – stoned instead of brick work) 9/18/2018
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Stones - Introduction 9/18/2018
Today, stones form an important source of aggregate (both coarse and fine) for concrete 9/18/2018
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Stones and Rocks - Definition
Stone can be defined as the natural, hard substance formed from minerals and earth material which are present in rocks Rock can be defined as the portion of the earth’s crust having no definite shape and structure. Some of the rock forming minerals are quartz, mica, dolomite, felspar, etc The various types of rocks from which building stones are usually derived are granite, sandstone, basalt, trap, marble, slate and limestone 9/18/2018
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Classification of rocks
Stones used for masonry construction must be hard, durable, tough and sound. It must be free from weathered patches of material, cracks and other defects Stones for building purposes must be obtained by quarrying from solid massive rocks and not by breaking boulders Geological classification Igneous rocks Sedimentary rocks Metamorphic rocks Physical classification Stratified rocks Un-stratified rocks Foliated rocks – leaves of a book Chemical classification Siliceous – quartz, sand, etc Argillaceous – clay minerals Calcareous – carbonate of lime 9/18/2018
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Classification Based on Geographical formation
Igneous Rocks Also known as primary rock, un-stratified or eruptive rocks Formed as a result of solidification of molten mass lying below or above the earth’s surface Eg. granite, basalt, trap, dolerite 9/18/2018
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Classification Based on Geographical formation
Sedimentary rocks Also known as aqueous or stratified rocks The various weathering agencies eg, rain, sun, air, frost, etc break up the surface of earth. Rain water carries down these broken pieces to the rivers and settle in the water because of changes in velocity where the sedimentation takes place in layers and gets consolidated in horizontal beds Rocks are soft, and can be easily split EG. SANSTONE, SHALE, SILT STONE, LIMESTONE, GYPSUM, ETC 9/18/2018
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Classification Based on Geographical formation
Metamorphic Rocks Formed from igneous or sedimentary rocks as a result of the action of the earth movements, temperature changes, liquid pressures, etc Can be foliated or non-foliated Foliated (layers)– slate, gneiss, etc Non-foliated (no layers but more colour)– marble, serpentine 9/18/2018
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Classification of rocks based on Physical classification
Stratified rocks Unstratified rocks Foliated rocks – leaves of a book Stratified Rocks Show distinct layers along which the rock can be split due to the deposition of organic and inorganic particles. eg. Sandstone, limestone, shale, slate, marble, etc Un-stratified rocks Do not show any stratification and cannot be easily split into thin layers eg. Granite, basalt, trap Foliated Rocks Have a tendency to split up only in a definite direction. Eg. gneiss result of heat and pressure Most of the metamorphic rocks except marble and quartzite 9/18/2018
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Quarrying of stones Good stones are obtained by quarrying from solid rock formations and not from loose boulders Boulders are not fit for important constructions Quarry refers to places exposed to air like a stone outcrop from which we extract the building stones. Mine refers to the places where we extract mineral resources like coal, precious stones, etc 9/18/2018
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Quarrying methods Depends on the type of stone, its use and the type of geological formation If the rock formation consist of horizontal layers at shallow depths, we may be able to quarry them in layers by hand tools If the stone is one whole crystalline masses, we may have to blast them with explosives If we need regular building blocks, we use channeling machines Quarrying with hand tools Quarrying by use of channeling machines Quarrying by blasting with explosives 9/18/2018
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Quarrying with hand tools
Old method Digging and excavating – soft stones like laterite using axes, chisels and shovels Heating – layered rocks. If the surface is heated by fire, the differential expansion separates the layers 9/18/2018
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Quarrying with hand tools
Old method Wedging – cracks and fissures, steel wedges are driven and the pieces are separated 9/18/2018
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2. Quarrying by use of channeling machine
One of the faces should have an exposed face Channels are made by the channeling machine driven by steam, compressed air or electricity Width – cm Length – 24m Depth – m Granite and other rocks 9/18/2018
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3. Quarrying by blasting Does not produce regular sized stones for masonry Blasting using gunpowder (charcoal, saltpetre, sulphur) or chemical explosives – dynamite, blasting powder, cordite, etc 9/18/2018
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3. Quarrying by blasting Used for the manufacture of stone aggregates or ballast for railways Breaks up the block into irregular blocks and pieces which can be later crushed to give coarse or fine aggregate Can be used for irregular work like random rubble masonry 9/18/2018
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Natural bed of stone Seasoning of stone
Original bed of formation of the stone is called natural bed Stone should be placed such that the load line is at right angles to the natural bed Seasoning of stone The fresh cut stone has some moisture called quarry sap. The stone has to be dried to make it harder, weather resistant and compact. This drying of stone is called seasoning of stone. 6-12 months 9/18/2018
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Dressing of stone Seasoning of stone
A quarried stone has rough surfaces. It needs to be dressed to obtain a definite and regular shape Seasoning of stone The fresh cut stone has some moisture called quarry sap. The stone has to be dried to make it harder, weather resistant and compact. This drying of stone is called seasoning of stone. 6-12 months 9/18/2018
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Stone veneering Wall faces are covered with polished tiles or slabs cut from selected stones like sandstone, marble, granite, etc. Such work is called stone veneering 9/18/2018
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Common building stones and their uses –
Uses in buildings Masonry Flooring Roofing Paving roads Aggregates for concrete 9/18/2018
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Common building stones and their uses
S.No. Type of work Stones used 1. Heavy engg. Works – bridge piers, break waters, monuments, etc Fine grained granite and gneiss 2. Masonry work in industrial areas exposed to smoke and fumes Granite, quartzite, compact sandstone 3. Facing work of buildings Marble, granite or sandstone 4. General building work Limestone and sandstone 5. Carvings and ornamental works Fine grained granite, marble and soft sandstone 6. Fire resistant masonry Compact limestone and sandstone 7. Floor pavings Marble, slate, sandstone and granite 8. Foundations of buildings with high water table Granite. quartzite Uses in buildings Masonry Flooring Roofing Paving roads Aggregates for concrete 9/18/2018
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Criteria for selection of stones
Stone for masonry – for rough work – random rubble Soft stones like lime stones and sand stone can be dressed more easily than granite Stone for pavements – hard stones of any type – pavings, walkways or drive ways Stone for flooring – heavy duty flooring Granite, marble flooring ( Cant wash with acids) Marble, kotastones can take polish Cuddapa stones - kitchen platforms 9/18/2018
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Criteria for selection of stones
Lime stones Criteria for selection of stones Stone for facing work in buildings –attractive colours, durable Impervious stones – granite, marble Pervious stones – lime stones Stone for concrete aggregates – moderate strength – limestone High strength concrete - granite 9/18/2018
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Lime stones 9/18/2018
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Sandstones 9/18/2018
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Slate walls during construction Decorative Slate stone wall tile
Slate stone roof tile Slate walls during construction Decorative Slate stone wall tile 9/18/2018
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Granite 9/18/2018
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Marble 9/18/2018
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Properties of stones Crushing strength
Igneous and Metamorphic – N/mm2 Sedimentary – N/mm2 Appearance Density (specific gravity greater than 2.7) Durability Easiness of dressing Fire resistance Fracture – well cemented and sharp fracture Impact resistance Hardness Resistance to wear Seasoning – Some freshly cut stones contains quarry sap. They should be dressed at freshly quarried stage and should be kept apart (seasoned) for the moisture to evaporate 9/18/2018
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Deterioration of stones – Main causes Preservation of stones
Alternate wetting and drying Alternate freezing and thawing (melting) Harmful substances in the air near sea shores or industrial areas Living organisms – growth of vegetation, bacteria or worms that live on rocks Movement of chemicals between materials – Limestone absorb MgSO4 from other stones like sandstone Nature of mortar – chemicals Temperature variation Waterfalls and Rainfalls – falling from great heights or chemicals in it Wind – contain sand and dust Linseed oil – raw and boiled Solution of alum and soap Solution of barium hydroxide Paraffin Paint Coal tar 9/18/2018
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Artificial stones Terrazzo is a man-made conglomerate. A conglomerate is a group of rocks which are cemented together usually using limestone. Terrazzo Mosaic 9/18/2018
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Artificial stones Mosaic is the art of covering and decorating a surface or item with small mosaic tiles. Mosaic tiles or tesserae can be made from any hard material – glass, mirror, tiles, pebbles, shells, ceramic shards and more Terrazzo Mosaic 9/18/2018
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