As the snow melts each spring, the challenge of maintaining gravel roads presents itself again. In the last few years many Maine towns have met this challenge by mounting a low cost grading attachment in place of the snowplow on their light to medium duty plowtrucks, taking advantage of the vehicles they are already using for winter road maintenance.
In the past, similar tine rake devices, often called “rock rakes” were towed behind trucks or mounted behind tractors, primarily to clear rocks and debris. By redesigning and strengthening this “rock rake,” moving it to the front of the truck and providing a hoist adapter that permits depth control from the operator’s seat, the unit has evolved into a more of a grader-rake. It can still perform the functions of a rake with the advantage of clearing debris ahead so that the vehicle does not have to drive over it first. However, it can also smooth and reshape gravel surfaces as a sort of quick and efficient mini-motor grader.
Although the grader-rake is not intended to take the place of a town’s motor grader, some towns, especially those with narrow roads, little surfacing material and tight budgets have found this truck mounted attachment to be more serviceable than a grader for some situations. The selectmen’s secretary in the little town of Acton, Maine comments that “The boys prefer it (the grader-rake) to the grader. It’s faster, cheaper, and does a better job on many of our roads because there is so little material to work with.” Continue reading “Using a Plowtruck for Gravel Road Maintenance” →

Water sitting on a gravel surface causes many problems when it is worked on by passing vehicles. Even a small amount of water sitting in a depression on a traveled way can cause a pothole to develop or can become mixed up with the road surface to create another hazard to travel — mud. Therefore, the primary maintenance concern for most gravel roads and driveways is shaping the surface to get water to run off and away as quickly and effectively as possible.

The more a road surface is sloped, the quicker it will shed water and less likely it will become potholed or muddy, within reason. Maintenance and safety considerations limit the recommended pitch for the surface of unpaved roads to a range of 3/8 to 3/4 inch per foot of lane width. Rounding off to 1/2 inch per foot for practical reasons, this means that a 20 foot wide roadbed (two 10 foot lanes) should have a centerline that is five inches higher than the edge of the road. That is 1/2 inch of rise for each foot of width from the center to the edge. If properly maintained, this “crown” is adequate to inhibit the formation of potholes and other surface breakdown. By contrast, paved roads generally require only half this pitch, or ¼” per foot or 2 ½” for a 10′ lane. Other paved surfaces like driveways and parking lots require even less pitch to shed water, about one inch per ten feet. The integrity of the paving material is generally adequate to keep potholes from forming, even if there is an occasional “birdbath”. Continue reading “Getting your Crown in Shape” →

“Cut out the potholes, don’t just fill ’em or they’ll come right back.”
Good advice that we all try to follow. But what do you do when there are 6″ deep potholes in a road with a processed gravel surface that’s only 3″ thick. If you cut all the way to the bottom of the potholes you’re digging up coarse base material, forcing you not only to have to remove stones from the finished surface but also to have to lose material that should have remained in the road bed. Continue reading “Getting to the Bottom of POTHOLES!” →

Why does the road crew for the Town of Foster, RI have a rig that looks like it should be stuck on the back of a tractor hanging from the front of its snowplow trucks?

Several years ago, Foster had a problem keeping its dirt roads in decent shape during the summer until they tried maintaining them with something called a Front Runner. This device is actually an attachment that fits onto the front of the towns trucks in place of the snowplow. It is pushed ahead of the truck and provides a very effective means of grading the roads while getting rid of ruts and potholes.

When Foster found itself hit with early and late winter snowstorms, the kind that come either before the ground has frozen, or even worse, after it has turned to springtime mud, highway foreman Walter May decided to try the Front Runner as an alternate to conventional plows (which dig up the soft roads). The results were so favorable that Walter now has a second Front Runner primarily for snow removal. Continue reading “Foster, Rhode Island” →

Anyone who’s tried to plow a gravel road before it has frozen knows the problem. Snowplows are designed with an aggressive angle of attack to peel packed snow from a road and roll it up and out of the way. If a road surface is soft, the plow doesn’t know where the snow stops and the gravel begins. Consequently, gravel often ends up in the side ditch or on lawns along with the snow. Not only does this mean damage to the road and a cleanup job for the spring, but it can also mean damage to the plowtruck, plow and even the operator.

Although plow shoes are designed to hold a cutting edge off the surface, they often prove inadequate when roads are soft.To provide extra support, some operators weld a cutting edge flat across the bottom of the plow (parallel to the road) to increase its surface area. Other operators simply lift the plow just enough to keep it off the road which works fine until the truck encounters uneven ground or a wheel falls into a pothole. In either case, the prudent operator goes slower than normal to reduce damage if the plow should happen to dig in. Continue reading “Those Early Winter Snowstorms…” →

What do you get when you add a bucket of stone to a bucket of mud? According to one explanation I’ve heard, you just get a bigger bucket of mud. Of course this point of view might be a bit suspect because it came from a geotextile salesman. The point is well taken, however, that adding something to a muddy road often has little effect, and can, in fact, sometimes make matters worse because of increased agitation of an already sticky situation.

I have found, however, that there are times when little else can be done except to add aggregate to a section of road that appears bottomless for a while in the Springtime. WHAT you add and HOW MUCH OF IT is what makes the difference between success and gooey failure.

From years of road maintenance and site development, I’ve found that the only practical way to treat a mudhole is to add enough coarse aggregate to fill the entire hole, essentially bridging the weak spot with strong supporting material. This material needs to be extremely porous and can consist of rocks or large crushed stone (not peastone), and should contain virtually no sand or fines. The goal is to provide enough of this coarse material so that, once it’s in place, each rock or stone touches another, and the mud that was there now just fills the gap between stones. The emergency repair takes on the characteristics of the fill material rather than the mud it has replaced. Continue reading “A Bucket of Stone plus a Bucket of Mud = ?” →