To build an unpaved road that performs well and is cost effective, there are important steps that need to be followed.
When some people think of a dirt road, they might think of the good old days or tiny tracks in the middle of nowhere, but that’s not the case: as of 2013, 35% of all America’s roadways were unpaved, according to the United States Department of Transportation’s (DOT) Bureau of Statistics. That’s over 1.4 million miles of dirt roads.
Unfortunately, not all are created equal. Some roads are hastily built and others are poorly maintained. But with some careful consideration, gravel roads can serve a community effectively and affordably for years. Here are 7 key points to keep in mind to make the best gravel road.
1. Understand Your Needs
Before construction begins, it is necessary to understand the needs and uses of the area where the road is going. Heavy industrial vehicles used for farming, for example, can wreak havoc on a gravel roadway if it is not strong enough, as the DOT exmplains. Commercial trucks and agricultural equipment have steadily been increasing in both size and horsepower, resulting in increased tire pressures and greater damage. Gathering information on both the type and frequency of traffic will help you plan accordingly.
2. Build on a Strong Foundation
A strong foundation is essential in any construction project, from homebuilding to gravel roads. Ideally, you will be building your road on strong, deep subgrade. There are times, however, when it is impossible to avoid weak and wet soils (like a section of a road passing through swamp or wetlands). This may require a process called undercutting, where the weak soil is excavated and replaced, according to the state of Indiana. If the roadway is wide enough, it may be raised with new materials. The other involves using a woven or non-woven fabric to cover the inadequate soil before being covered by the new material.
3. Choose the Right Materials
The best materials for a project are typically determined by the location of the future road. Depending on a region’s climate and available resources, among other factors, the ideal aggregate will vary, but all should drain well. It is important to select the proper gravel for its respective use as either surface and base material.
Gravel produced as fill material for building is made up of sand-sized particles that lack binding particles. When used on a road, this type of gravel remains too loose and unstable. Testing and purchasing the best gravel in the prospective environment is well worth the investment, as it will pay off in lower maintenance costs in the long run.
4. Build From the Bottom Up
This may seem like a straightforward concept, but it’s worth the extra attention. In the same way choosing the right materials is crucial, the order in which they are applied, and how, can be the difference between a great, cost effective gravel road and a weak one that needs constant expensive repairs. For example, base gravel should not contain much clay or other fines and should have larger “top-sized” stone for strength and good drainage. If used as surface gravel, the materials will fail to form a binding crust and make maintenance much more difficult.
5. Drainage, Drainage, Drainage
In many ways, all the most important steps of gravel road construction are related to drainage. Roads that allow water to properly drain off the surface and out of roadbed soils are much easier to maintain and therefore less costly. Conversely, gravel roadways with poor drainage can never fully be maintained. Any standing water on or adjacent to the road will compromise its integrity, as the state of Alaska explains. Beyond selecting a good profile of gravel, basic techniques such as keeping the correct shape of the road, in addition to culverts, drains and bridges, and under drains, will all prevent water from pooling.
6. Apply Proper Palliatives
Once the road is near completion, applying palliative solutions will further bind the gravel, serving as both a strengthening and protecting agent. EK35®, offered by Midwest Industrial Supply, Inc, uses nontoxic fluid and resin binder to capture and stabilize surface aggregate. This not only immediately boosts the strength of the road in the first 48 hours after construction, it actually becomes more stable as roads see more traffic. Such palliatives require fewer applications, saving valuable maintenance time and money.
Whether accomplished through simple grading or soil stabilization, keeping a regular and thorough maintenance schedule will ensure the road performs well. Improper grader use can actually damage the road, so correct technique is essential and often best left to professionals. Materials will periodically need to be recovered and/or replaced in thin and worn out places, but investing in Midwest’s solutions can reduce lifecycle costs by 50%.
(Main image credit: Sharon Mollerus/flickr; Vilseskogen/flickr)