Surface Course of Rigid Pavement
The surface course is the layer in contact with traffic loads. It consists of the PCC slab which is the stiffest layer and provides the majority of strength.
- The surface course can vary in thickness but is usually between 150 mm (for light loading) and 300mm (for heavy loads and high traffic).
- Portland cement concrete is the “white stuff” used as pavement material.
How Portland Cement and Portland Cement concrete is made ?
- Portland cement is made by heating shale, limestone and small amounts of iron-ore to very high temperatures.
- It is then cooled and ground into a fine powder.
- Gypsum is added to the powder to keep the powder from hardening instantly when water is added.
- Portland cement concrete is made by mixing portland cement with water, and coarse and fine-size rocks.
- All the materials, including the right amount of air bubbles, must be in the correct proportions in order for the mixture to harden properly.
- A properly mixed concrete has all the rock pieces completely coated all the way around each piece.
- It initially can be more expensive.
- The life expectancy of portland cement pavement varies, as little as 20 years or more than 40 years.