Los Angeles Abrasion Test for Coarse Aggregates as per IS 2386: Part IV (1963)

 Introduction:

The Los Angeles Abrasion Test is a widely used test method to determine the hardness of aggregates. The test is conducted on the aggregates that are used in the construction of roads, pavements, and other infrastructures. The test measures the resistance of aggregates to abrasion and the results are used to determine the quality of aggregates.

Objective:

The objective of this lab writeoff is to conduct the Los Angeles Abrasion Test as per IS 2386: Part IV (1963) and determine the hardness property (wear and tear resistance) of the aggregates.

 

Apparatus:

1. Los Angeles abrasion testing machine
2. Sieve set with a pan and lid
3. Balance with an accuracy of 1 g
4. Abrasive charge consisting of 12 steel balls with a diameter of 48 mm and a weight of 390 g
5. Oven
6. Sample of coarse aggregate

Procedure:

1. The sample of coarse aggregate is oven-dried at a temperature of 100-110°C for 24 hours.
2. The dry aggregate sample is weighed and the weight is recorded as W1.
3. The aggregate sample is placed in the Los Angeles abrasion testing machine and the machine is operated at a speed of 30-33 rpm for a total of 500 revolutions.
4. After the completion of the test, the aggregate sample is sieved through a sieve of 1.70 mm size and the material that passes through the sieve is collected in a pan.
5. The material that is retained on the sieve is weighed and the weight is recorded as W2.
6. The Los Angeles Abrasion value is calculated as follows:

Los Angeles Abrasion value = ((W1-W2)/W1) x 100

Results:

Sample weight before test = W1 = _______________ g 

Weight retained on 1.70mm sieve = W2 = _______________ g 

Los Angeles Abrasion value = ((W1-W2)/W1) x 100 = _______________%

Conclusion:

The Los Angeles Abrasion Test is a reliable method to determine the hardness property of aggregates. The results obtained from this test are useful in evaluating the quality of aggregates used in the construction of roads, pavements, and other infrastructures. The test is conducted as per IS 2386: Part IV (1963) and the results obtained are reported as Los Angeles Abrasion value.

Limiting Values:

The limiting values for Los Angeles Abrasion value for aggregates used in pavement layers depend on the type of pavement and the layer in which the aggregates are used. Here are some general guidelines:

1. For bituminous concrete wearing course: The Los Angeles Abrasion value should not exceed 30%.

2. For bituminous concrete binder course: The Los Angeles Abrasion value should not exceed 35%.

3. For bituminous concrete base course: The Los Angeles Abrasion value should not exceed 40%.

4. For cement concrete pavement: The Los Angeles Abrasion value should not exceed 50%.

It is important to note that these are general guidelines and the specific limits may vary depending on the project specifications and requirements. The quality of aggregates used in pavement layers is critical to the performance and durability of the pavement, and therefore it is important to ensure that the aggregates meet the specified requirements.