Types of Adhesion Test on Aggregates

Adhesion tests on aggregates are essential to determine the bonding strength between the aggregate and the binder material. There are six types of tests conducted to evaluate adhesion:

1. Pull-off Test:
This test involves applying a force perpendicular to the surface of the aggregate to measure the adhesion strength. It helps in assessing the bond between the aggregate and the binder material.

2. Scratch Test:
In this test, a sharp tool is used to scratch the surface of the aggregate to evaluate the adhesion between the aggregate particles and the binder. The depth and width of the scratch are measured to determine the adhesion strength.

3. Peel Test:
The peel test involves separating the aggregate from the binder material to assess the adhesion strength. It helps in understanding how well the aggregate is bonded to the binder material.

4. Shear Test:
In shear tests, a force is applied parallel to the surface of the aggregate to determine the adhesion strength. It helps in evaluating the resistance to sliding between the aggregate and the binder material.

5. Centrifuge Test:
The centrifuge test involves subjecting the aggregate-binder mixture to centrifugal forces to simulate the stresses experienced in the field. It helps in assessing the adhesion strength under dynamic conditions.

6. Bond Strength Test:
This test measures the bond strength between the aggregate and the binder material using specialized equipment. It provides valuable information about the adhesion properties of the aggregate.

These different types of adhesion tests on aggregates help in evaluating the bonding strength between the aggregate and the binder material, which is crucial for ensuring the quality and durability of the pavement construction.