Post on 14-Apr-2017
Aggregate
Pic.. In aggregate working
introduction Aggregate can be defined as a
material that is used as filler for filling up the voids during construction. It comprises of a broad category of coarse material that is used in construction. Aggregates are the most mined category of minerals in the world. They have been in use for thousands of years with significant use taking place back during the Roman Empire. The invention of concrete resulted in demand for aggregate since it is a crucial material for preparation of concrete.
principale
Working Principle of AggregateAggregates impart strength by reinforcing
the composite material, that is to say, they fill up the voids to form a substance that has more compressive strength. By filling up the space that is available, aggregate ensures that the structure doesn’t fail when load is applied to the structure.
Main Types of aggregate
Types of Aggregate SandGravelSlagGeo-synthetic Aggregates andCrushed stoneGranular materialRecycled concrete
Conti…
Application
Applications of Aggregate FoundationsFrench DrainsSeptic Drain FieldsRetaining Wall DrainsFoundationsRoadsRailroadsConcrete Constituent
Measures of aggregate size
Precautionary Measures Make sure that
segregation of aggregate does not occur.
Depending upon its usage, it should be dry/wet.
Make sure that it has passed the sieve size test and is correctly graded.
Different applications require different standards of aggregates; be wary of that.
AggregateAggregate
Based on Unit weight
Normal
Sand, gravel, crushed rocks, granite, basalt
Light weight
Broken bricks, air cooled slag, bloated clay
Hevy weight
Barite, Magenetite , limonite, hematite
Based on size
Fine
coarse
Based on shape
Rounded, irreguler, angular falky, elongated
Based on texure
Glassy, smooth, grannuler, crystaline etc..
Types of aggegates
o Classification of aggregate based on unit weight
1. Normal weight aggregates 2. Light weight aggregates 3.Hevy weight aggregateso Classification of based on size 1. fine aggregate 2. coarse aggregate
Conti..
o Classification based on shape 1.Rounded aggregate 2.irreguler aggregate 3.Flaky aggregate 4.Elongated aggregateo Classification based on texure Glassy : black , fint smooth: chert , slaet , marble , some
rhyolite Granular: sandstone , oolites crystalline: fine ,midiume , coarse Honeycombed and prous: scoria , pumice
trass
Classification of aggregate based on unit weight
1. Normal aggregates Normal weight aggregate can be used in all
types of works. The specific grevity of these aggregate is about
1.5 to 2.7. The density of concrete produce using is about
2300kg/m3 to 2600kg/m3 . Natural aggregates
SandGravel
crushed rock as greniteBasaltQuartziltSandston
Conti….
Artificial aggregatesBroken bricksAir cooled slagsintered fly-ashBloated clay
Conti….
2. Light weight aggregate Natural agg. pumiee scoria
rise husksaw dust
Conti…
Aetificial aggregatefoamed slagbloated clayexpanded shalesintered fly ash
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3. Hevy weight aggregatebaritemagnetitelimonitehematite
Classification based on size
1.Fine aggregate (F.A) The size of aggregate 4.75mm and
smaller is called fine aggregate2. Coarse aggregate (C.A) The size of aggregate bigger then 4.75
mm is called coarse aggregate
Conti..
Fine aggregate
•Size <4.75 mm• Bulking is more (up to 40%)•F.A fills voids between C.A•Eg. Natural sand, stone Coarse
aggregate
•Size >4.75 mm•Bulking is very small & neglected.•C.A gives strength to concrete•Eg. Gravel , crushed stone