Chapter 9, Problem 9.1QP

To determine

Write the difference between tar and asphalt cement.

Explanation of Solution

Difference between tar and asphalt cement as in Table (1):

Asphalt cement	Tar
Asphalt occurs in natural form or by means of a by-product of petroleum refinery. It is sticky, adhesive, elastic, and easily able to stretch flex and bend without breaking.	Tar cannot occur in natural form; it is obtained as a by-product when manufacturing water-gas and coke.
Asphalt is more weather resistant.	Tar is more temperature susceptible, usually used to coat aggregates that are more water resistant.
Hot mix paving asphalt creates odor that can be strong and persistent.	Tar has an aromatic odor.
Asphalt molecules tend to be aliphatic (referred as a straight chain).	Tar tends to be aromatic (referred as cyclic or ring).
Asphalt fume causes health hazards such as skin rash, fatigue, headache, and also skin cancer.	Fumes from the heated tar cause health hazards to human beings such as severe eye and skin irritation.
Uses: They are largely used for pavement construction and maintenance. It is used as glue with aggregate particles to create the asphalt concrete.	Uses: They are broadly used in road works because it is superior and also used for preserving timber.