The greatest cost in the pavement lifecycle is the initial construction cost followed by future overlay or reconstruction costs. The surface type selection will determine the number of pavement layers and their thicknesses and the ultimate costs. In general, hot mix asphalt concrete will have lower initial costs in most parts of the United States. Portland cement concrete can be more competitive in regions with poor quality or expansive soils.
Over a pavement’s life cycle the pavement surface will become damaged and maintenance will be necessary. In most instances, not addressing damage will create life safety issues and shorten the pavement performance life.
Asphalt concrete pavements will have surface oxidation resulting in a rough surface, cracking, and eventual failure. This can all happen without a single vehicle on the pavement.
When vehicles are added in, repetitive vehicle weight will eventually create cracking and potholes. To slow oxidation, a seal coat – something like a paint, is required. Pavement patching and a thicker asphalt concrete layer is needed. A seal coat is relatively inexpensive, but a reapplication is usually necessary every four to six years. The timing of an overlay will depend upon the accumulation of pavement distresses. A thinner pavement section will likely need an overlay sooner than a thicker section. We usually see a need for an overlay at 12 to 14 years old.
A well designed and constructed Portland cement concrete pavement can have lower life cycle costs than HMAC over a 30 to 35-year life span. This is because PCC will typically not have the resurfacing or reconstruction costs. Hot mix asphalt concrete will have maintenance costs throughout its life cycle and possibly two overlays in 35 years. We have a client with 50-year-old PCC pavements. As with high initial PCC construction costs, maintenance work will also be more expensive. Typical problems are deteriorated joints and slabs breaking into pieces and shifts under vehicles. Replacement costs will be high when a PCC pavement finally requires replacement.
We believe it is cost effective to maintain an existing pavement surface as long as possible with routine maintenance treatments rather than allow deterioration until resurfacing or replacement is necessary. How do you know what is best for your pavements? The pavement performance data in a pavement management system can provide the basic information for analysis.
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