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## What Is Abrasion Test?

**The abrasion Test** measures **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 and 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**of 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 a 1.70 mm IS sieve.- The material size of 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 the aggregate sample** = W1 g

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

**Abrasion Value Formula**

**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,

**What is the Micro-Deval Test?**

Nowadays these** Micro-Deval** abrasion tests have gained **popularity **and acceptance as an **economical **and accurate **procedure **for **abrasion tests**.

Also, this **method **was developed in **France **in the 1960s and provides a **measure **of the **resistance** of **abrasion**, toughness, and **durability **of mineral aggregates as they are **ground **with balls in the presence of **water**.

### Conclusion

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

From the** table 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 the 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 the abrasion value test?**

**The abrasion** Test measures 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 the 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 in an oven dry.

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

**What is the use of an 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 its 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).

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