Specification of Coarse Aggregate | | | |
Coarse AggregateCoarse Aggregate consists of natural occurring stones (crushed, uncrushed or broken). It should be hard, strong, dense, durable, and clean. It must be free from veins, adherent coatings and injurious amounts of disintegrated pieces, alkali, vegetable matter and other deleterious substances. It should be roughly cubical in shape. Flaky pieces should be avoided. It should confirm to IS: 2383(I).
Grading of coarse aggregate
Coarse Aggregate should be either graded or single sized as specified in the table given below.
Characteristics of coarse aggregate1. The coarse aggregate is clean, hard, non porous, free from lumps of clay and vegetable matter.
2. Water absorption of aggregate is not more than 10 % of its weight after 24 hours immersion in water.
3. Angular and roughly cubicle particles are ideal. River gravels make the best coarse aggregate.
4. Aggregate is chemically inert material.
5. Brick aggregate is not used in RCC work.
| S. No. |
IS Sieve size of Designation(mm) |
Percentage
40mm |
passing
20mm |
(by weight)
16mm |
for nominal
12.5mm |
| 1. |
75 |
100 |
---- |
---- |
---- |
| 2. |
37.5 |
95-100 |
100 |
---- |
---- |
| 3. |
19 |
33 - 70 |
95-100 |
100 |
---- |
| 4. |
16 |
---- |
---- |
95 - 100 |
100 |
| 5. |
11.2 |
---- |
---- |
---- |
90 -100 |
| 6. |
9.5 |
10 - 35 |
25 -35 |
30 - 70 |
40 -85 |
| 7. |
4.75 |
0-5 |
0-10 |
0-10 |
0 - 10 |
Deleterious substances in coarse aggregateCoarse Aggregate should not contain any of the following deleterious materials.
- Pyrites
- Coal
- Lignite
- Mica
- Clay
- Alkali
- Soft fragments
- Sea shells
- Shale or similar laminated material
NOTE: The maximum quantity of deleterious materials should not be more than 5% of the weight of the aggregate when determined in accordance with IS: 2386(I).
Precautions while using coarse aggregateThe following precautions should be taken while using coarse aggregate in RCC (Reinforced Cement Concrete) Work. 1. Aggregate should be stacked on a hard, dry and level patch of ground. 2. Coarse aggregate should not contain any material liable to attack steel reinforcement. 3. Aggregate which are chemically reactive with alkalies of cement should not be used. 4. Proper graded material should be used for achieving good bond stress. 5. Aggregate should be washed with clean water before the use.
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| 10 Comment(s) |
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| | By S P Singh - On 1/23/2013 1:02:12 PM | | how is the quality of dala(UP) aggregate and Prism champion cement. |
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| | By S L Gupta (Civil Engg) - On 1/23/2013 1:02:12 PM | Dear S Psingh Your quarry is not clear, write in detail so that one can be able to ansewer the quarry. |
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| | By Anonymous - On 1/11/2011 5:45:26 PM | | i need to know about the artificial coars aggregate |
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| | By Anonymous - On 9/7/2010 9:14:19 AM | | This article is helpful to learn more about coarse aggregate. However, I wonder how to crush those corase aggregate so that they can be fine enough to be used in road, construction, etc. |
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| | By Sunil Pathik - On 8/3/2010 1:03:58 PM | | Very Very helpful Article. Great work in deed. |
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| | By Anonymous - On 2/21/2010 8:23:28 PM | | Very helpful article.On one specific point (not extracted from your article)-Is"3mm dry coarse aggregate " related to the sieve size of the designation in Col. 1 of the table in your article? |
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| | By Vinod Kumar - On 2/16/2008 11:08:08 AM | | Nice ArticleGreat work Gharexpert Team |
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| | By Vinod Kumar - On 2/16/2008 11:07:56 AM | | Nice ArticleGreat work Gharexpert Team |
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| | By Vinod Kumar - On 2/16/2008 11:07:45 AM | | Nice ArticleGreat work Gharexpert Team |
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| | By RAJKUMAR1956 - On 2/5/2008 4:37:10 PM | | Congrats, Ghar Expert is going in very healthy direction towards acquaitance of basic and unending knowledge before going for a good house and construction activities. |
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