What is a Premix and Types of Premix
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.Premix usually refers to a substance or object which is mixed in an early stage in the manufacturing and distribution process.
Types of premix
- Sheet Asphalt
- Asphalt concrete
- Prime-coat
- 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:
- 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.
- It helps to bind the finer particles of aggregate together in surface of the road base.
- 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.
