By Tony Wight
As we at LeeBoy like to say, “Paving is still the same as it was from day 1, but the specs and tolerances have changed.” We are all called to give a better product and we are all subject to testing for density and thickness. Being off just a little can keep you from being paid or fully paid.
More and more people are turning to technology to meet needs. For the paving industry, that ends up being grade control. Whether you are using TopCon, MOBA or some other brand you want to be as exact as possible in water flow and asphalt yield. Both can save a contractor money and heartache.
Grade control has been the most popular for the highway contractor, being that they have to meet ride specification and want to control thickness. We all know that a contractor needs to maintain a minimum thickness to meet specifications. If you think about the math, just a ¼ of an inch over a 5 mile job at 20 feet wide adds up to thousands of dollars in lost profit.
Let’s talk about how grade control works. In one brochure the controller is explained as a “stop watch” and that is exactly how it works. The head sends out close to 100 sonic beams per second, timing how long it takes for that beam to hit the controlled base and return to the head. If the time is shortened this means the distance the beam travels is shorter. Meaning the screed is lower. The controller then sends a signal to raise the tow point to bring the screed up. The sonic signal taking longer means the screed is too high and the controller lowers the tow point to bring the screed down. I have run a controller over a credit card and watched the tow point move. This is how close the grade control can keep your tolerances.
Grade control has been used on highway jobs for years and the question is, will it help on commercial jobs? The short answer is yes. Think about just ¼ inch extra over a large parking lot. That is a lot of wasted dollars. It is better to use grade control to hold a tighter yield. Also think about the running track and controlling smoothness and slope for water runoff. Many contracts call for a minimum slope with penalties if they are not met.
The point at which a contractor should invest in grade control is based on the majority of their work. Someone doing driveways and small parking lots may not see enough return on savings to justify the expense. A contractor that does large parking lots, streets and even walking trails can see enough savings on the first couple jobs to pay for the investment. Remember, grade control works on averages, so the longer the pull, the better the average.
Some things to remember when considering grade control are not only the return on investment, but crew training. If your team does not understand how to use grade control, they will not want to use it. So whatever you decide to buy, make sure it comes with a good training program. Another would be sub base. Do you control the sub base or is it handed to you by the GC? If there are high spots in the base then you will have thin asphalt in those places. It is best to have the base put in with grade control if you are going to use it for the asphalt.
There are also several choices of grade control; single grade or joint matcher, dual grade and dual grade and slope. Each have their own benefits. Single grade or joint matcher is just that it controls one side of the screed, matching a joint or curb reveal. This leaves the opposite side to be controlled manually. This is easier to use and works well on smaller jobs as well as some bigger jobs. The dual grade is just what it says, it matches both sides to a controlled reference point be it a curb, string line or the last pass. This is more money and takes a little more set up and training. The last is dual grade and slope. It is the most expensive and takes the most training and setup.
So, if grade control is something you have considered, first look at what work you do. Get buy in from your crew. Also, talk to the dealer that sells pavers; they most likely have a relationship with a local grade control supplier and can tell you who has the best product and service in your area.
Tony Wight is a LeeBoy Territory Manager. He can be reached via email at firstname.lastname@example.org.