The entire runway is 3200 m long, of which 250 m is considered part of the ramp. Pavimentos Universal milled at a depth of 140 mm for the 250 m. Recycled materials helped to build the ramp.
Ramp paving was accomplished with a Cat® AP1000D Asphalt Paver. The ramp work required a trucking pattern similar to what was used for the longer, flatter stretch of runway. "We used 25 trucks no matter what mix we worked with," Polo said.
Because of the warm, humid weather in Cartagena, Polo was able to have the mix delivered hours in advance of its placement. "It takes the mix a long time to cool," he said. "We usually have most of the trucks lined up before we start paving."
Many trucks arrived at the jobsite before midnight, when Polo's crew was first allowed to pave. Pavimentos Universal had to be off the runway by 5 a.m., so Polos had the luxury of knowing there would be no transport problems before starting with that night's paving.
"If there were problems getting the mix there, we could choose to not work," he said. "That's better than starting and not being able to finish the work, especially on a job like this. If we started here, and had problems, it could create many complications."
That approach also meant his calculations for the amount of mix must be precise. "The Cat Paver is very exact in the amount of mix it uses," he said. "The paver's consistency helped us calculate the proper amount."
The average of fines in the mix was 2-4 mm. The placement of the mix on the ramp portion also was unique: The paver worked across the width of the runway, instead of the length of the runway. The ramp portion is 250 m long, and 40 m wide. That meant the paver worked in 40 m increments.
"That is what the specifications called for," Polo said. "Because of the fine materials, the consensus was that it made more sense to pave in shorter increments, and then reach compaction goals. With that level of fines, there can only be a few passes with the roller before the danger of damaging the mix becomes very real."
Paving over the width, and not length, of the ramp also meant less chance for wasting material during the compaction process. Less of the costly material is lost when rollers work across the runway than if they had rolled (and pushed) material toward the top and perhaps over the end.
The material also had to cool to at least 130° C before rolling. There were joints to consider too. This led Pavimentos Universal to place a mat at a width of about 8 m; then leave the adjacent 8 m unpaved; then place another 8 m; then skip the next 8 m, and so on. Each night it placed five lifts of 40 m each. After completing the first three lifts, and leaving two of five stretches unpaved, the paver returned and filled in the missing lifts.
"This allows the asphalt to cool enough so that we can work on it, and compact the joints, while also making sure we don't damage the fine material by working it too early and too extensively," Polo said.