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Paver and screed operators must closely watch the appearance of the pavement surface during the paving operation because it is easier to correct a minor deficiency as it occurs. It becomes more difficult to fix a defect after the pavement has been compacted. Operators work to control the amount of material in the hopper with an uninterrupted flow of mix through the tunnels to the augers.

Proper control of the head of material is the responsibility of the screed operator. If the screed extensions are deployed, there is usually a need to engage tunnel extensions. Proper positioning of the strike-off plates is important, as is the height of the screed extensions and whether they are front-mounted or rear-mounted extensions. The screed needs to vibrate to provide optimum pre-compaction to the pavement, and it's set-up of amplitude and frequency depends upon mix type and thickness.

Some contractors use a nuclear densometer to check density of the newly paved panel behind the screed. By confirming uniform density across the width of the panel, subsequent compaction can more easily achieve percent within limits (PWL) target specifications for the project.

There are many reasons why uniform density may not be achieved. Lack of uniform density can be due to problems at the plant, loading of the haul vehicles, transport, delivering the mix into the paver, or even paver set-up and paving practices. Even laborers on a paving crew can create problems through mix-handling techniques. At times, even the best compactor train is hard-pressed to compensate for non-uniform density in the pavement prior to rolling. This can make achieving uniform final density in the pavement unlikely.

Resolution
Most pavement defects can be solved in-process, by following the adage, "If we can see it, we can fix it." All members of the paving crew need to be trained to look for deficiencies as they perform their duties. And they should realize their responsibility to advise the appropriate crew member so the deficiency can be corrected immediately. The following are examples of common pavement defects, their causes, and resolutions.