Deleterious Material in Aggregates - Civil Engineering

Friday, 1 June 2018

Deleterious Material in Aggregates

Deleterious Materials In Aggregate

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 in aggregate 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

Deleterious Material in Aggregates
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 affects the strength of concrete.