Monday | October 23, 2017

Paving Basics Make a Better Job

To watch how the mix behaves in front of the screed, you can paint it with an orange or white spray paint. You’re watching to be sure it tumbles in an end-over-end motion, churning as the augers chu... [Full View]

Balance the screed and the tractor; drive the paver so that the chain goes smoothly down the chalk line you’ve painted for the lane. Wherever that chain falls, the endgate follows.

Paving basics start before you call for a haul truck. To keep segregation—both material and temperature segregation—out of your project, clean up the paver.   The push roller bar on the front of the paver can get gummed up with asphalt mix during the paving shift. The best thing to do is clean that up at the end of the day so it’s not a problem the next morning.

You know that spot you’ve set aside where haul truck drivers can clean out their beds without spilling cooled, clumped mix into the paving lane? Take the paver there and clean it off. Clean the nooks and crannies that might otherwise hide clumps that would fall off and cause a cold spot in the mat tomorrow.

Guide Bar Endgate

Balance the screed and the tractor; drive the paver so that the chain goes smoothly down the chalk line you’ve painted for the lane. Wherever that chain falls, the endgate follows.

It’s important to clean the endgates as well. If you have a clean endgate, it will be less likely to tear the mat or joint. It’s the gummed up asphalt stuck to its edges or under its ski that will grab the mat and make a problem for you when paving. Clean that off and find a way to get heat all the way out to the ends for the smoothest strikeoff.

Other basic tips include heating up the whole tractor and screed before you begin paving. Then don’t forget your best practices for smooth paving, such as running evenly between loads. Have the haul truck back almost to the tractor and then stop. The paver operator will nudge the paver forward and push the truck with the tractor.

If the paver’s hopper starts to run low on mix, it’s time to slow down. If the hopper gets so low that you have a gaping hole leading back to the head of material, you’re starving the augers, which means you’re not paving a good mat.

When you’re feeding material to the augers properly, they will turn at a consistent rate and churn the material in an end-over-end motion. You can watch the material being laid next to the endgate. If it’s being pushed forward like snow in front of a snow plough, you need to adjust the paving speed and auger rotation. If the material is falling end-over-end, you’re doing it right. Sometimes that’s difficult to see in the shadows. I recommend taking the paint wand and spraying a bit of the mix there in front of the end gate. You can watch the painted material more easily as it moves and assess its motion.

Paint the Mix

To watch how the mix behaves in front of the screed, you can paint it with an orange or white spray paint. You’re watching to be sure it tumbles in an end-over-end motion, churning as the augers churn it. You don’t want the augers or endgate to merely push it forward like a snow plough. The paint makes the motion easier to see. You know if the head of material is alive.

Also take the time to watch what’s happening behind the screed. Get the straightedge out and lay it across the width of the lane. Do you see light underneath there? Is it the amount you built in for the crown of the road or do you have a slope miscalculation? Make sure you have your tape measure close at hand to double-check everything from the base course up.

Notice that one particular crew had trouble on a base layer with the automation. On the right side of the mat, there’s a line in the mat from the weight of the screed plate. When it was noticed, the screed operator adjusted numbers in the system and the line quickly disappeared as the automation corrected the tow point and leveled out the screed plate. Check out the before and after pictures to see balanced compaction across the screed plates.

Above all, keep well-trained veteran workers in positions where they can assist younger or newer workers. As a consultant, I see workers helping one another on the job to make projects go more smoothly, more quickly and more safely. That’s great to see. Keep that spirit of camaraderie alive in your crews and reward those employees who pay attention to the back-to-basics details like those we list here.


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