In Iran since ancient times are unknown and it was used for building insulation. Physical pitch black, brown and viscous colloidal mixture of the hydrocarbons that have been formed. Family mainly include coal tar and bitumen, tar and bitumen residues are mineral and oil. Some of the hydrocarbon bitumen, sulfur, oxygen and nitrogen are.
General Features tar and Basic features striking black binder include:
Impervious to moisture and water
Electrical insulation
Elasticity
The stability against acids, bases and salts
Adhesion to other materials
Some major flaws in the black binder include:
Their mechanical and physical properties with temperature changes, are smooth.
High heat decomposed, burned and turned to charcoal and lose their adhesion properties.
High pressure against the change form
In mineral oils and some solvents such as sulfur dissolved carbon.
Contaminated soil in moist environments and lose their stickiness.
Due to these features, the types of bitumen in the building industry have many applications. One of these properties tend to stick to rigid surfaces and lack of moisture and water in it. The adhesion to the surface of the body and also will depend on the pitch. To create stickiness action should tarry material, capable of adhering to the surface wind. As stated, this adhesion eliminates moisture in the surface.