ASPHALT ANSWERS
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 .
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
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January 2021