Friday, 1 June 2018

Deleterious Material in Aggregates

Deleterious Materials

The materials whose presence in aggregates may adversely affect the strength ,workability & long-term performance of concrete are termed as deleterious materials.

These are considered undesirable constituents.The total amount of deleterious materials should not exceed 5% as per IS 383-1970. 

The Deleterious Materials Found in The Aggregates

The deleterious substances found in the aggregates are as follows:

a)Organic matter consisting of decayed vegetable matter
b)Coal & Lignite
c)Clay lumps
d)Shale


Deleterious Material in Aggregates

Deleterious material present in the aggregates may affect the concrete as follows:


a)The organic matter interferes with the chemical reaction of hydration .

b)The clay & other fine materials present in the form of surface coating interfere with the bond between the aggregate &cement paste.

c)Presence of shale & other particles of low density adversely affect the strength of concrete.


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