Implementing Process Control
FHWA Wants Road Construction Industry To Use Process Control
"We want you to build roads that have predictable performance," Ryan Rizzo, pavement and materials engineer for the Federal Highway Administration (FHWA), told contractors attending the recent Michigan Concrete Paving Association (MCPA) 35th Annual Concrete Pavement Workshop in Troy.
"So, when we engineers say that we want a service life of 25 years from concrete pavements on the interstates, we want at least 80 percent of them to last 25 years," Rizzo said.
"At FHWA we are moving to try to get our industry to look into process control more and more, so that we can have a more reliable prediction of pavement life. It makes it easier to maintain the highway system." Rizzo made the distinction between product control and process control.
"We taught you to do product control and we insisted that it be random samples, because that is the way that we as owners are going to accept the product. However, if you're doing process control, you can't wait for random samples. With process control you need to know that the work is humming along like it's supposed to be. You might grab some samples or test readings every morning. That's not random; it's called rational sampling. It's something that tells you something about your process," Rizzo said.
"One thing that I believe in is that product control, such as cylinder breaks, are too late in the game to do anything about process control. You've already made the product and now the owners are deciding how much to pay you for it."
Michigan Department of Transportation (MDOT) Chief Deputy Director Kirk Steudle reported that approximately 89 percent of the freeways in Michigan are in good condition and the department projects it will get to approximately 91 percent by 2007, somewhat short of its 95-percent goal. Approximately 84 percent of bridges on the freeway system are in good condition and the department predicts it will reach 86 percent by 2007.
"That's a little short of our goal, but it's going up. When we started this in the mid-1990s, approximately 69 percent of our freeway system was in good condition. There has been huge improvements in the overall network," Steudle said.
On the non-freeway side, approximately 83 percent of MDOT's roads are in good condition and the department predicts they will get to 84 percent by 2007. Approximately 86 percent of MDOT's non-freeway bridges are in good condition. MDOT has met its goal for non-freeway bridges.
22-Jan-2006