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## What Is Abrasion Test?

**Abrasion Test** is the measure of **aggregate toughness** and abrasion **resistance** such as crushing,** degradation **and disintegration. **This test** is suggested by** AASHTO T 96** or **ASTM C 131:** Resistance to **Degradation** of Small-Size** Coarse Aggregate **by Abrasion and **Impact in Los Angeles Machine.**

The **aggregates **are used for the **surface course **of the **highway pavements** and they are subjected to** wearing due** to the movement of traffic. **(L****os**** ****Ange****les**** abrasion test ASTM c131)**

**When** vehicles **travel on the road,** the soil particles **present between** the pneumatic tires of the **vehicle **and the road **surface creates** the abrasion **effect on aggregates.** The steel plate **wheels of animal-driven** vehicles also **cause significant** abrasion of the r**oad surface.**

**Therefore,** the aggregates used in **road construction** must be hard** enough to resist **abrasion. **The resistance** offered by **aggregate to abrasion** is determined in the** laboratory by the Los Angeles Test machine.**

**The Working principle** of the** Los Angeles** abrasion test is **to produce **abrasive action by use of **standard steel balls,** which when **mixed with aggregates** and rotated in a **drum for **some **specified time** for a specific **number of** revolutions also **causes an impact** on aggregates.

**The percentage **wear of the **sample aggregates** due to** rubbing with steel** balls is determined and is known as **Los Angeles Abrasion Value.**

**Read More: ****Aggregate Impact Value Test, Procedure, Result & Standards**

**Los Angeles Abrasion Test**

The** abrasion test of aggregate **on aggregates is done for the** following purposes:**

- To find out the
**Los Angeles abrasion value of aggregate.** - To find the
**suitability of aggregates**for use in road**construction projects.**

**Apparatus used for** **Abrasion Test**

**The apparatus is standardized as per IS: 2386 (Part IV) – 1963 consists of:**

**Los**Angeles**abrasion machine**

**Abrasive charge balls:**Cast iron or steel balls, approximately 48mm in diameter and each weighing between 390 to 445 gm; six to twelve balls are required

**Sieve:**1.70mm , 2.36mm, 4.75mm, 6.3mm, 10mm, 12.5mm, 20mm, 25mm, 40mm, 50mm, 63mm, 80mm IS Sieves.

**The balance**of capacity**5 kg or 10 kg**is used.

**Oven Drying.**

**Miscellaneous**elements like**a tray.**

**Read More: All Aggregate Test and Procedure**

**Los angeles Abrasion Test Procedure**

**The aggregate**s sample **consists of clean **aggregates dried in an **oven at 105° – 110°C**. The aggregates **sample should** conform to any of the** grading shown** in the below table.

**Select**the**size of aggregate**to be used in the**test such that**it conforms to the**grading to**be used in**construction,**to the maximum**extent possible.****Take**exactly**5 kg of the sample**for grades A, B, C & D, and**10 kg for grading**E, F & G.**Choose**the abrasive**charge balls**as per**Table 2 depending**on the**grading of aggregates.****Place the aggregates**and abrasive**charge balls**on the**cylinder and fix the cover.****After**that Rotate the**machine**at a speed of**30 to 33 revolutions per minute.**The number of**revolutions**should be**500 for grades**A, B, C & D and**1000 for grading**E, F & G.- The
**machine**is stopped**after the specified**number of**revolutions**and the aggregate sample is**discharged to a tray.** **The entire stone**dust made from a**machine is sieved**on 1.70 mm**IS sieve.**- The
**material size**more than**1.7 mm size**is weighed correct to**one gram.**

**Table 1: IS Recommended Test Samples – *Tolerance of ± 12 percent** permitted.

**Table 2: Abrasive Balls Charge Selection**

**Read More: Download the IS Codes of Aggregates for FREE Here: IS: 2386 (Part I-VII)**

**Observations**

The **original weight of aggregate sample** = W1 g

The** weight **of the **sample retained** = W2 g**Weight **sample passing **1.7mm IS sieve** = W1 – W2 g

**Abrasion Value = (W1 – W2 ) / W1 X 100**

**Sample Calculation**

Let the weight of the aggregate be **W1 = 5000 gram**

Weight of the aggregate sample retained** W2 = 2100 gram**

Weight sample passing 1.7mm IS sieve = W1 – W2 g =** 2900 gram**

Abrasion Value = (W1 – W2 ) / W1 X 100 = (2900/50000) X 100 = **58**

**Results**

**Los Angeles Abrasion Value of Aggregate = 58**

**IS Recommended Los Angeles Abrasion Value of Aggregate** **for Pavements**

A** Los Angeles test **is performed to find the** hardness of aggregates***.* On the basis of this value, the **suitability of aggregates** for different **road constructions **can be judged as per IRC specifications as given,

### Conclusion

Following the** Los Angelos Abrasion Test **as mentioned above, we derived the** abrasion value of the sample as 58.**

From the** table given above, **the suitability of **aggregates used** for the** pavements** can be known.

**For the sample** calculation that **was done here** having an **abrasion value of 58,** the aggregates** can be employed **only for the** WBM sub-base course**. Its maximum permissible **abrasion value is 60.**

**Watch Video:** **Los Angeles Abrasion Test**

## FAQs:

**What is abrasion value of aggregate?**

The** abrasion value of an aggregate **is the value that determines aggregate toughness and abrasion resistance. It includes properties of aggregate such as crushing value, degradation, and disintegration.

**What is abrasion value test?**

**Abrasion Test** is the measure of aggregate toughness and **abrasion** resistance such as crushing, degradation and disintegration. The percentage wear of the sample aggregates due to rubbing with steel balls is determined and is known as **Los Angeles** **Abrasion Value**.

**How do you do abrasion test?**

The sample of aggregates of various sizes are placed in the L.A. Abrasion Machine and the machine is rotated at 30-33 rpm.

The resultant sample is taken out and washed over a No. 12 i.e 1.70mm sieve and placed for an oven-dry.

The percent loss i.e the difference between the original mass and the final mass has to be calculated.

An L.A. Abrasion loss value can be calculated as for example, a value of 40 indicates that 40% of the original sample mass passed through the sieve.

**What is the use of abrasion test?**

1. To find out what could be the Los Angeles abrasion value of aggregate before use in specific operations.

2. To determine the suitability of aggregates for use in road construction projects.

3. Ultimately Hardness of an aggregate can be determined by knowing the properties of aggregate.

**What are the three types of abrasion?**

**TYPES OF ABRASION**

1. **Flat Abrasion** is also known as a plane or surface Abrasion.

2. **Edge Abrasion** i.e. at collars and folds

3. **Flex Abrasion**(flexing and bending).

**How do you do abrasion test?**

The sample of aggregates of various sizes are placed in the L.A. Abrasion Machine and the machine is rotated at 30-33 rpm.

The resultant sample is taken out and washed over a No. 12 i.e 1.70mm sieve and placed for an oven-dry.

The percent loss i.e the difference between the original mass and the final mass has to be calculated.

An L.A. Abrasion loss value can be calculated as for example, a value of 40 indicates that 40% of the original sample mass passed through the sieve.

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