How to Pave on a Curve

TThe team at D-Squared Construction Limited, Ottawa, Ontario, shared several pictures for the producer profile in our September quality control/quality assurance (QC/QA) edition. While selecting which images would highlight their new hybrid asphalt plant, I noticed an excellent example of attention to detail, teamwork among laborers and quality paving technique. Let’s use those two pictures to show your crewmembers some best practices for paving against a curved supported edge.

These two photos are from a project taking place on Heron Road in Ontario, Canada. The crew used live-bottom trailers to deliver mix to a Shuttle Buggy material transfer vehicle (MTV). The MTV fed a hopper insert in the paver. The screed is extended to get the full lane width in one pass, but let’s talk about trying to pave all the way to a curb with an obvious curve in it.

The last thing a good crew wants to do is weave with the paver.

A good operator will pave in a straight line, which offers the best joint for matching on the next pull. Instead of trying to steer the paver to meet the meandering curb, the screed operator has a couple of options. It’s not recommended to let the screed get out of balance, so he doesn’t necessarily want to extend one side to keep the ski against the curb as the paver travels down the lane. The challenge there is keeping the head of material consistent and feeding non-segregated material all the way to the endgate when you take the screed out of balance like this.

The other option, which Paving Consultant John Ball recommended, is to lift the endgate no more than half an inch to allow mix to bleed out under the ski as the paver moves past the problematic area in the lane. This puts extra material in the trouble spot.

“If you leave the endgate up a little bit, all you have to do is let the mix bleed out a little and work it with the lute,” Ball explained.

When the paver has moved down the lane, the laborer goes into action, leveling the mix with the lute.

This is where teamwork is vital. Another laborer should be at the ready to shovel hot mix from the head of material and cast it exactly where the lute artist needs it to ensure even coverage.

With the mat level across the mainline and into the curves and crevices, the roller operator and plate compactor operator can ensure a smooth finish.

– BY SANDY LENDER

Paving Consultant John Ball suggested contractors raise the endgate no more than half an inch to let the mix bleed out from under the ski to reach the extra space next to the curb. Notice that the worker wearing the hardhat numbered “2” is indicating with the lute exactly where additional mix is needed. The worker in the white hardhat is casting the material to the lute. Both photos courtesy of D-Squared Construction

While the roller operator pinches the longitudinal joint, the laborers have taken the high area off the manhole cover. Using a 30-inch lute, the laborer is luting and leveling out the area near the curb. You can see the laborer in the white hardhat getting mix to fill in at the curb, so the lute artist doesn’t have to stop and wait on material. This is a notable example of teamwork.

BUILT TO CONNECT

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Designed with safety and operator comfort in mind, the Shuttle Buggy® SB-3000 material transfer vehicle features adaptive cruise control, bright LED lighting, four-wheel steering for easy transport and ground-level maintenance access for added convenience. Operators can rely on clear sightlines and the ground operator is safely protected inside the structure of the machine. The Roadtec SB3000 is the perfect blend of traditional craftsmanship and modern technology.