INTRODUCTION
Asphalt cement is widely used for the pavement construction in most countries. The performance of the asphalt pavement directly depends on the properties of the asphalt cement. One of the important properties of asphalt cement is the contact angle, which is an indication of the resistance of asphalt cement to flow. The contact angle can also be used to indicate the wetting characteristics of asphalt cement. The determination of the contact angle of asphalt cement can provide valuable data to traffic engineering.
PRINCIPLES
The contact angle of asphalt cement is measured using a Contact Angle Goniometer, a device specially designed for the task. The goniometer is a device that measures the angle formed between a stationary base and a contact surface of asphalt cement. The contact angle is measured using the calibrated scales on the goniometer. The contact angle measured is the angle formed between the asphalt cement and the base of the goniometer.
PROCEDURES
1. Prepare a sample of asphalt cement in a container. Ensure that the sample is homogenous and free from dirt and foreign matter.
2. Roll out the asphalt cement on a smooth surface. Remove any lumps or obstructions.
3. Place the goniometer on the asphalt cement surface and the base of the goniometer should be in contact with the asphalt cement sample.
4. Carefully set the blade of the goniometer at the contact angle and adjust it so that it is in line with the base of the goniometer.
5. Read the contact angle and record the result.
6. Repeat the process for several different specimens of asphalt cement.
7. Calculate the average of the contact angles measured.
RESULTS
Table 1 shows the contact angle results of the asphalt cement samples tested.
Table 1: Contact Angle Results Sample Contact Angle (degrees)
1. 82
2. 87
3. 89
4. 91
5. 93
Average 90.2
DISCUSSION
The average contact angle of asphalt cement is given in Table 1. The results show that there is a relatively high contact angle of 90.2 degrees. This indicates that the asphalt cement has a good resistance to flow and does not readily wet. This is in line with the characteristics of asphalt cement, where high contact angles improve the strength and reduce the possibility of slippage on asphalt pavements.
CONCLUSION
The contact angle of asphalt cement was measured using a Contact Angle Goniometer. The results indicate that the asphalt cement has a relatively high contact angle, with an average of 90.2 degrees. This indicates that the asphalt cement has good resistance to flow, which is important for preserving the integrity of an asphalt pavement.
