Building stones
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Building stones
- 1. Department of Civil Engineering Iqra National University Peshawar BUILDING STONES Civil Engineering Materials (CE-116) Lecture 4 Engr .Muhammad Farhan Khattak
- 3. Building Stone • Stone: A construction material derived from rocks in the earth’s crust and mixture of two or more minerals. • Mineral is a substance which is formed by the natural inorganic process and possesses a definite chemical composition and molecular structure. 3
- 4. Building Stones • Stones used in most historical places – Pyramids of Egypt – Taj Mahal of Agra, India – Great wall of China – Greek and Roman structures – Quaid’s tomb in Karachi – Shahi mosque in Lahore – Forts at Rohtas, Lahore – Lloyd’s Barrage at Sukkur 4
- 5. History Taj Mehal ?? The Great Pyramids ?? 5
- 6. Civil Engineering Uses • Construction of residential and public buildings • Construction of dams, weirs, harbors, bridge abutments, etc • Face work of structures for appearance and ornamental value • Road metal and railway ballast • Aggregate for concrete • Stone dust as substitute for sand • Thin slabs for roofing, flooring and pavements • Limestone for manufacture of lime, cement, etc 6
- 7. Building Stones • Stone as building material lost its importance due to – Advent of cement and steel – – Structural strength can not be rationally analyzed – Transportation difficulties – Dressing problems 7
- 9. Classification of Rocks Rocks Geological Physical Chemical Igneous Sedimentary Metamorphic Stratified Un-Stratified Foliated Argillaceous Siliceous Calcareous Practical Granite, Basalts Marble Limestone, Sandstone, Slate 9
- 10. Classification of Rocks • Geological classification – Igneous rocks (primary, un-stratified, eruptive) – cooled down molten volcanic lava (magma). Basalts and granites. – Sedimentary rocks (aqueous, stratified) – gradually deposited disintegrated rocks. Sand stones and lime stones – Metamorphic rocks – transformed due to great heat and pressure. lime stone to marble, shale to slate(Shale is a fine-grained, clastic sedimentary rock composed of mud that is a mix of flakes of clay minerals and tiny fragments (silt-sized particles) of other minerals, especially quartz) 10
- 11. Igneous Rock 11
- 14. Classification of Rocks • Physical classification – Stratified rocks – separable distinct layers. Cleavage(Cleavage is the tendency of crystalline materials to split along definite crystallographic structural planes) plane of split visible. Slate, sandstone, lime stone – Un-stratified rocks – no sign of strata, cannot be easily split into slabs. Granite, basalt, trap – Foliated rocks – having tendency to split up only in a definite direction 14
- 18. Classification of Rocks • Chemical Classification – Siliceous rocks – containing silica SiO2 (sand) and silicates. Granite, basalt, quartzite, etc – Argillaceous rocks – containing clay or alumina Al2O3. Slate, laterite, etc – Calcareous rocks – containing calcium carbonate or lime. Limestone, marble, etc 18
- 19. Characteristics of Good Building Stones • Appearance & color – uniform color, lighter shades preferred, free from clay holes, bands or spots • Structure – Not dull in appearance, crystalline homogenous close grained is good, stratification should not be visible. • Weight – heavier are compact, less porous, good for hydraulic structures • Strength – generally compressive strength needed, igneous rock stones are stronger • Hardness– resistance to abrasion, friction and wear. Hardness scale 1 to 10 • Toughness – Withstand impact, vibrations, moving loads • Dressing – uniform texture and softness for fine surface finish 19
- 20. Characteristics of Good Building Stones • Porosity and Absorption – exposed surface absorbs rain water forming acids causing crumbling action. Cyclic freezing and thawing of pore water • Seasoning – hardening and weathering affect due to evaporation of quarry sap and formation of crystalline film. 6 to 12 months for proper seasoning • Weathering – resistance to action of weather • Resistance to fire – free from calcium carbonate or oxides of iron • Durability – compact, homogenous and less absorptive is more durable • Cost – quarrying, transportation, dressing and installation 20
- 22. Quarrying and Dressing • Quarrying: An art of extracting stones from the rock beds of different varieties used for general building work and broken stones for roads and concrete work, etc • Quarry: The place from which stone is obtained by digging or blasting etc 22
- 23. Selection of Stones • Heavy engineering works bridges, piers, abutments, break waters, docks, light houses – granite • Buildings facing the sea – granite, fine grained sandstone • Buildings in industrial area – granite, compact sandstone • Arches – fine grained sandstone • Building face work – marble, close grained sandstone • Fire resisting structure – compact sandstone • Road metal and aggregate for concrete – granite, basalt, quartzite • Railway ballast – coarse grained sandstone, quartzite • Electrical switch board – slate, marble 23