concrete technology
TRANSCRIPT
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Concrete
• One of the very important and widely used material in construction
• The Grade of the concrete is specified by its 28 day’s cube strength (E.g. M20 means the cube strength is 20 N/sq.mm)
• Concrete used on works is specified according to IS 456 (2000).
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•Consists of Portland cement, water, and aggregate ( Fine& Coarse )
•Cement, water and fine aggregate – mortar
-Admixtures added for specific purposes like
– Entrain numerous microscopic air bubbles– Retard the initial set of the concrete– Waterproof the concrete , etc.
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Concrete chainCement supply sand supply Coarse aggregate
supplyWater supply
Transporting, unloading and stacking
Gauging
Mixing Slump test
Cube test
Transporting
Placing
Compaction Curing
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PROPORTIONING CONCRETE MIXTURES• For successful utilization, the mixtures must be properly
proportioned ( Mix design )
Concrete Mix Design-IS 10262
Designed to achieve a defined
• workability
• strength
• durability
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BATCHING AND MIXING OF CONCRETE MATERIALS
• Batching is weighing or volumetrically measuring and introducing into the mixer the ingredients for a batch of concrete
• A batch is the quantity of concrete mixed at one time
More accurate to measure by weight
• As per IS 4925 : 1968 - specification for concrete batching and mixing
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Slump test to test workability
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Cube test to test the strength
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It is a mold used to shape the concrete and support the
concrete until it attains sufficient strength to carry its
own weight.
Formwork system
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Introduction No desirable structure can be built without the use of formworks.
Such is the importance of formwork that it constitutes 30% of Cost 60% of Time Construction Apart from that the quality of concrete finish and soundness of concrete depends very much on the formwork system.
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Types of Formwork
Formwork can be divided into two approaches :
Traditional approach
Systematic approach (System formwork)
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Traditional formwork system in Progress
Wooden posts (ballies)
A network of wooden beams to support the sheathing
System formwork in Progress
Collapsible type props (CT props)
A network of wooden H-beams to support the sheathing.
Pictures and sketches taken from L&T- DOKA formwork manuals
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Column Formwork
Pictures and sketches taken from L&T- DOKA formwork manuals
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Wall Formwork
Pictures and sketches taken from L&T- DOKA formwork manuals
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Beam Forming Support
Pictures and sketches taken from L&T- DOKA formwork manuals