Question

4. The Los Angles abrasion test is applied to natural aggregate particles used in construction of pavements. Is it true? Justify your answer.

5. Discuss the effect of the number of revolutions of the rotating drum used in the Los Angeles abrasion test on the Los Angeles value.

6. A test group A used 11 steel balls while another test group B used 9 steel balls for conducting the Los Angeles abrasion test of aggregates. Compare the Los Angles values obtained by these two groups in terms of percentage difference

Answer 1

4.

Yes, It is true and los angles test can be done on natural aggregates which is used in pavement construction. Mostly we are using natural aggregates for the pavement construction because it is easily available natural material and desired quality to resist the load of the vehivles.

5.

If we increase number of revolution then we get higher los angles value and if we reduce revilution number the we het lower los angles value. In los angles abrasion test we have calibrate the machine with known hardness material and we found if revolution number is around the 500 rpm then we are getting approximately exact result that's why we are keeping 500 rpm for los angles machine and  If we increase number of revolution then we get higher los angles value and if we reduce revilution number the we het lower los angles value.

6. If group A used 11 steel balls while another test group B used 9 steel balls for conducting the Los Angeles abrasion test of aggregates, out of both cases we get higher los angles value in case of 11 steel ball becasue these ball provide more resistance on surface of aggregates as compare to 9 steel ball.

As there is no mathematical formula to calculate los angles abrasion value using number of ball but we can relate by resistance provided by ball

as number of ball increases resistance is increases.

% difference = (11-9)/9*100 = 22.22 %

we get 22.22 % higher in los angles abrsion value of 11 stell ball as compare to 9 steel ball

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