Premix - Types of Premix - Purpose, Uses, Applications of Premixes

Definition:

Something that is mixed or blended from two or more ingredients or elements before being used. This term is used usually for concrete in civil engineering.

Types of premix

1. Sheet Asphalt
2. Asphalt concrete
3. Prime-coat
4. Tack-coat

1. Sheet Asphalt

A premix of bitumen and sand (with or without filler) and containing coarse aggregate that exceeding 30%, laid in thickness varying from ¾" to ½" (dense carpet, stone metal is discarded and chipping limited to 30%, the rest being sand)

2. Asphaltic concrete:

A premix of bitumen and sand (with or without filler) and not less than 30% by weight of mineral aggregate of size larger than sand, mixed and laid at high temperature around 35 degree Fahrenheit and required heavy binder generally are 50-60, 60-70, 70-80, 85-100.

3. Prime Coat:

The initial application of binder to an absorbent highway surface prior to the construction of a wearing coat.

Purpose of Prime Coat:

1. It assist in promoting and maintaining adhesion b/w the road base and the bituminous surfacing. By pre-coating the surface of the road base and wearing coat are glued by penetrating the prime coat in the voids near the surface.
2. It helps to bind the finer particles of aggregate together in surface of the road base.
3. If the application of the surface is delayed for some reason it provides the road base if the application against the detrimental affect of rainfall and light traffic.

4. Tack Coat:

The initial application of binder to and existing given surface, to ensure thorough bond b/w the new construction and existing surface.