Concrete pavements are a long term solution to providing a pavement for both light and heavy traffic loading. Concrete, when designed and installed correctly, can last longer that asphalt pavements. Concrete pavements can be found most often used in parking lots, access drives, and roads.
There are 2 primary types of concrete pavements, plain and reinforced. Concrete pavements are typically a minimum of 6” thick and can be as thick as 14” or more for pavement with heavy truck traffic expected. Concrete parking lot’s and drive approaches are commonly 6-8″ thick and concrete roads are commonly 8-14″ thick depending on the expected traffic loads.
Reinforced concrete pavement consists of wire mesh or rebar placed inside the concrete. Plain concrete has no reinforcing, but often still has ‘Tie-Bars’ and ‘Load Transfer Dowels’ installed within it. Tie-Bars and Load Transfer Dowels both reinforce the joint some but both serve separate primary functions.
Load transfer dowels are often used in concrete pavements at transverse contraction and expansion joints to transfer the traffic loads from bay to bay, increasing the overall life of the concrete pavement and reinforcing the joint from vertical differential movement and deterioration. These dowels are often smooth and can be epoxy coated or uncoated bare steel. Load transfer dowels may be placed at the proper location either mechanically (with the paving machine) or on ‘baskets’ of bare steel. They may also be placed in predrilled holes and grouted or epoxied into place.
Tie-Bars are often utilized longitudinally to traffic, either between curb and pavement or between separate pours or lanes. Their primary purpose is to anchor adjacent slabs together, resist differential horizontal movement, and provide minor joint reinforcing attributes. Tie-bars are often deformed and may be epoxy coated or uncoated. They are placed either mechanically (with the paving machine) or on ‘baskets’ of bare steel. They may also be placed in predrilled holes and grouted or epoxied into place.
Concrete pavements or roads often have slopes or crowns which must be accounted for in the base prep, forms, and screed angle.
Concrete pavements can either be placed via the ‘fixed-form’ method or by ‘slipform’.
Fixed form is by placing wood or metal forms, inside which the concrete pavement is placed and finished, often manually.
For pavement slab pours with long spans between the forms, a truss or beam may be utilized to screed or strike off the pavement.
In slipform paving, a paving machine rides on crawlers or tires over the area to be paved. Concrete is deposited in front of or in the hopper of the paving machine which then spreads, shapes, consolidates, screeds, and float finishes the concrete in one continuous operation.
Concrete pavement may be ‘tined’ longitudinally or transversely which provides a grippable surface which provide added friction and skid resistance.