size of aggregate used in road construction |size of aggregate used in rcc |maximum aggregate size in concrete |sieve size for coarse aggregate
size of aggregate used in road construction |size of aggregate used in rcc |maximum aggregate size in concrete
AS PER IS CODE- THE AGGREGATE SIZE
As IS 456: 2000, As per Cl 5.3.3
For most works, 20 mm aggregate is suitable
When there is no restriction to the flow of concrete, 40 mm or larger aggregate is preferred.
In thin sections, small cover or closely-spaced reinforcements, considerations should be given to use 10 mm aggregate.
As per Cl 5.3.3.1
For heavily reinforced concrete members like ribs of main members, the nominal maximum size of aggregate should be usually restricted to
5 mm less than the minimum clear distance between the main bars
5 mm less than the minimum cover – whichever is smaller
AGGREGATE USED IN CONSTRUCTION
All types of aggregate are made of crushed igneous rock, granite rock, sedimentary rock & Metamorphic rock. all types of aggregate are used in construction for different purposes like roads, Streets and buildings and interior and exterior designing of houses.
Some of these we are familiar with that is fine aggregate & coarse aggregate containing different size and names like crushed stone, coarse sand, medium sand, fine sand,silt, clay and fine gravel , medium gravel , coarse gravel, pebbles cobbles and boulders.
coarse aggregate.
When the aggregate is sieved through 4.75 mm size the aggregate is retained is known as coarse aggregate.
Larger than 4.75mm size is coarse sand or aggregate, so coarse aggregate size arranging between 5mm to 256 mm or more.
YESTERDAY JOBS
Types of coarse aggregate and their size
- fine gravel -4 to 8 mm
- medium gravel- 8 to 16 mm
- coarse gravel -16 to 64 mm
- pebbles -4 to 64 mm
- cobbles -64 to 256 mm
- boulder – more than 256 mm
Size of aggregate used in construction
Size of aggregate used in construction:- it all depends on structure, whether it is plain cement concrete or reinforced cement concrete. The most commonly used aggregate size in construction are 20mm, 40mm and 75mm.
Aggregate size 20mm used in RCC structure, 40mm aggregate size used in PCC structure or mass concreting and 75 mm and more size used in retaining wall construction.
Size of aggregate used in PCC:-
PCC is plain cement concrete made of a mixture of cement, sand, aggregate and water without providing Steel, typically the most common size of aggregate used in PCC is 40mm. This is best, perfect, ideal and standard size of aggregate used in PCC like construction of PCC pavement, road, walkway or driveway.
Why 40mm size aggregate is preferred in PCC or mass concrete than 20mm?
For strength and workability, concrete with large size aggregate will require a lesser quantity of cement than concrete with a smaller size aggregate. In a mass concrete work or PCC the use of larger size aggregate will be useful due to the lesser consumption of cement, this will also reduce the heat of hydration and the corresponding thermal stresses and shrinkage cracks.
But in practice the size of aggregate cannot be increased to any limit on account of the limitation in the mixing, handling and placing of equipment.
In large-size aggregates surface area to be wetted per unit, weight is less, and the water-cement ratio is less which increases the strength. On the other hand in smaller size aggregates the surface area is increased which increases w/c ratio and lower strength is achieved.
In general, for strength upto 200 kg/cm2 aggregates upto 40 mm may be used and for strength above 300 kg/cm2 aggregate upto 20 mm may be used.
Size of aggregate used in RCC:-
RCC is reinforced cement concrete made of a mixture of cement, sand, aggregate & water provided with a steel bar. Typically the most common size of aggregate used in RCC structure like roof slab, column, beam & bridge deck is 20mm.
Maximum size of coarse aggregate used in RCC
Generally, 10mm,12mm ,18mm, 20mm and 25 mm size of aggregate used in RCC work. 10mm is minimum size, 20mm is most common size used and maximum size of coarse aggregate used in RCC is 25mm.
Size of aggregate used in road construction
Road construction needs mass concreting work, where there is no limitation for concrete flow, most common size of aggregate used in road construction is 40mm.
Size of aggregate used in retaining wall:
Retaining walls are relatively rigid walls used for supporting soil laterally so that it can be retained at different levels on the two sides. the most common size of aggregate used for retaining wall construction is 75mm.
Size of aggregate used in Bridge construction
Bridge slab & their deck construction provided with reinforcement need mass concreting work, where there is no limitation for concrete floor. The most common size of aggregate used in bridge slabs and their deck construction is 40 mm.
Size of aggregate used in concrete Dams
The dam is heavily concrete, and requires a lot of mass concreting work, in Concrete Dams 75mm aggregate size is provided near the face where their steel reinforcement is provided and 150 – 200mm maximum size of aggregate is provided in the rest of the dam.
size of aggregate used in road construction
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|aggregate size chart
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