Features
Bookmark Page
Most Read
Most Emailed
Email Story
Print Story
How Temperature Impacts Compaction
Paving crews can improve their finished pavement by keeping the rollers close to the paver and to each other
The proper position of the roller train behind the paver aids compaction efforts. The paver needs to place the mix while the temperature is between 350˚F and 290˚F. To the right of the paver are two "breakdown rollers" working in tandem in a temperature range between 320˚F to 250˚F. The arrow indicates where "density tests" are best conducted (after the breakdown rollers) and the furthest right section shows where finish rolling is done (temperature range 150˚F to 100˚F.)
By Dale Starry
As is true for much of life, learning often occurs as a consequence of negative, rather than positive, experience. Here is a prime example.
During the 2005 construction season, I visited a contractor's night paving project on three separate occasions. Each of these visits was made to provide practical assistance to this contractor to overcome failure and achieve a uniform and high density during the compaction process.
The contractor was not earning the available pavement density incentive from the agency even though the paving train on this jobsite incorporated an MTV to provide smoother paver operation and to help reduce segregation of the mix being placed.
During my first visit to this site in August, I noticed the breakdown compactor, or front compactor, was not following the paving train closely enough to satisfy best practices according to current industry definitions.
The temperature of the Superpave mix where the compactor was working, measured using an infrared thermometer, varied from under 240˚F to slightly more than 270˚F. The mix was simply not hot enough to permit the front roller to achieve target density within time available for compaction.
E-mail Article
Printer Friendly
