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. 

Deleterious Material in Aggregates

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 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) The presence of shale & other particles of low density adversely affects the strength of concrete.

Read More:

Types of Aggregates

Characteristics of a Good Fine and Coarse Aggregates