gravel road

Gravel roads are particularly susceptible to damage and deterioration. Keeping gravel roads in optimal condition requires regular grading.

There are no hard-and-fast rules for how often a gravel road should be graded. It depends on a variety of factors. However, as a rough guide, it's typically optimal to:

  • grade gravel roads with high traffic volumes as often as every 10 or so days
  • grade roads with medium to low traffic every three weeks to a month
  • grade low usage roads at least once a season (and after periods of heavy rain).

Factors that determine frequency of road grading

Road grading maintains a road’s surface and restores its geometry. This refers to the crowned cross-section that’s essential for an unpaved road to function optimally.

Many factors affect this ideal shape and they influence how often a gravel road should be graded.

Original road design

The original design of a gravel road impacts how regularly it will need grading. If the original road is not designed optimally and is poorly constructed, more frequent grading and reshaping will be necessary.

A gravel road must have a crowned surface and shoulder areas that slope away from the centre of the road. There should be ditches on either side. This crowned shape is critical for proper drainage and moisture control.

Without regular grading to reinstate and maintain this essential shape, even seldom-used gravel roads will suffer from blocked drainage and accelerated deterioration.

Climate

A region’s climate can decimate a gravel road. Extreme weather conditions usually mean a gravel road will require more regular grading.

Variable temperatures (freezing and thawing) and precipitation (rain, snow and hail) cause potholes and washboarding. Prolonged rain can cause significant rutting, loss of crown and deep ditches.

Standing water at any place within the cross section (including the ditch) is one of the major reasons for distress and failure of a gravel road. Substantial grading will be needed to reshape the road.

Rain and wind move material – gravel, soil and sand – into ditches. Light wind can destabilise a gravel road’s surface. Heavy winds can destroy it.

Traffic volume

Cars and trucks cause ruts, potholes and displacement of soil and gravel to the shoulder and adjoining ditches. Usually, a gravel road that’s seldom used will need less frequent grading than a gravel road that experiences high traffic volume. That said, frequency of grading will depend on other factors.

Traffic type

Volume is important, but the type of traffic also impacts the frequency of grading. Trucks and other heavy vehicles cause more damage to a gravel road’s surface than lighter vehicles.

Driving habits also impact gravel roads. Vehicles driving down the centre of a gravel road quickly flatten the crown.

Why it’s vital to grade gravel roads

Grading a gravel road is critical for the health of the road. It’s the best way to maintain its optimal shape and to rejuvenate a surface that’s suffering from the impact of the factors mentioned above.

Gravel roads are usually maintained by routine blading and adding gravel where necessary. Sometimes major grading and reshaping is necessary.

How to spot signs of wear and tear

It’s essential that managers and equipment operators inspect roads regularly. It’s their responsibility to keep a roadway properly shaped. Improper maintenance can lead to very quick deterioration of a gravel road.

Obvious signs of wear and tear in a gravel road include:

  • potholes and rutting
  • surface rills and gullies
  • material/gravel loss
  • flattened crown
  • loss of shoulders
  • filled-in ditches
  • pooled water.

Tips for grading gravel roads

Every road grading job is different. A unique set of variables must be taken into account, but these general tips can help achieve the best job:

How to Grade a Gravel Road: General Principles

Grading Gravel Roads: Motor Grader Adaptations

A gravel road that's well-constructed and properly graded at the outset will require much less on-going maintenance than a road that's not ideally constructed.

KH Plant

Now you know the factors that influence how often a gravel road should be graded, you need a grader.

At KH Plant, we specialise in restoring Caterpillar 140G, 140H and 140K motor graders and components to as-new condition – so you can get the benefits of a new motor grader at a fraction of the cost of a new machine. Contact us for more information or to discuss your needs.

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