As per dorry abrasion test, loss in weight is 33 gms, then find the coefficient of hardness.

Question

Question

This question was previously asked in

JKSSB JE Civil Jal Shakti 5 Dec 2022 Official Paper (Shift 1)

Answer 1

Explanation:

Concept:

Dorry abrasion test:

The test gives a measure of the resistance of aggregate to surface wear by abrasion.
Inadequate abrasion resistance of road-surfacing aggregates means an early loss of the texture depth required to maintain high-speed skidding resistance.
Coefficient of hardness is calculated from Dorry abrasion test and it indicates resistance against external weathering of aggregates.
\(Coefficient\,\,of\,\,Hardness= \,20\,-\,\frac{Loss\,\,in\,\,weight\,(gm)}{3}\)
For good aggregate, it should not be less than 17.
For medium quality aggregate, it is between 14 to 17.

Solution: given, loss in weight of aggregates = 33 gm,

∴ \(Coefficient\,\,of\,\,Hardness= \,20\,-\,\frac{Loss\,\,in\,\,weight\,(gm)}{3} =\,20\,-\,\frac{33}{3} =\,\, 9\)