Roads last anywhere from 18 to 25 years, depending on the material. But preventative maintenance is essential to get them to survive for a quarter of a century.
In this post, we explore how builders construct roads. We then look at some preventive maintenance techniques they can use to keep paved surfaces in good condition, even if they endure heavy use.
Road Construction: The Basics
Planning is the first step in building any road. Engineers and construction experts discuss what type of road they will build, what it should be made of, and where it will go. This part of the process can take several years for large projects, particularly if the proposed route runs through private property. Delays may also occur if modeling traffic volumes or environmental impact is challenging.
After planning comes to the bidding process. Here, regional authorities or city governments get contractors to bid on the project. Usually, the contract goes to the firm that bids the lowest, though they may need to meet additional conditions to qualify.
Once parties sign the relevant contracts, construction begins. The first step is to do all the earthwork. Moving machines shift the landscape around to ensure the road is flat and level. If it is uneven, surfaces placed on top will warp and crack easily.
Dump trucks, bulldozers, and graders continue moving the earth around until they construct a supporting shelf, usually raised a little off the surrounding landscape. They then add gravel to this structure and use heavy machines to flatten and compact it further.
After creating a level surface, they install storm drains as a priority. Drains prevent flooding if there are rain storms during work.
Next, it's time to add the paving. Construction firms use either concrete or asphalt. Traffic volume, location, cost, and the intended longevity of the road determine which material they use.
Asphalt roads are generally quieter and more beautiful. Factories heat the material to a high-temperature off-site (about 300°F) and then deliver it to the required location. Road builders then use special machines to spread it over the earth. Once it hardens, the main construction phase is complete.
Preventative Maintenance For Roads, And Why It Matters
There are many types of preventive maintenance designed to help roads last longer.
The first is patching. Here, workers fill excavated areas and potholes as soon as they appear, usually with gravel and asphalt. (Leaving them open allows water to infiltrate, worsening the damage. They can grow much larger quickly, so builders need to fill them in as fast as possible).
Another technique is called reshaping. Here, builders use a grading blade to scarify the road's damaged surface and rework the gravel subbase.
In some cases, roads require new asphalt overlays. These restore the road and make it smooth again. Builders use any existing asphalt as a base and add more on top. The bitumen in the asphalt helps it settle into all the little grooves underneath. Once it sets, the surface feels like a new road. In most cases, removing any existing surface material or performing additional hardscaping on the dirt and gravel shelf underneath is not needed.
Ditch cleaning is another valuable preventative maintenance technique. Ditches, besides roads, are important for removing surface water during rain storms. If they can't do their job, water starts pouring into the road, which damages the surface and puts drivers at risk. Ditch cleaning involves removing any debris that could prevent water flow.
Crack sealing also extends the life of roads. Asphalt emulsions and fiberized asphalt are the most common materials used for this purpose. Builders place these in cracks, preventing rain or ice from getting in.
Road preventive maintenance aims to keep roads as close to their original condition as possible. While they will eventually deteriorate, preventative maintenance can slow this process down considerably.
According to the World Bank, roads are one of the most important assets that a country can have. They are critical infrastructure without which society would grind to a halt.
The cost of failing to maintain roads is high. While it avoids expenses in the short term, it contributes to the degradation of society over the long haul. If local authorities fail to address issues while they are small, they can grow much more extensive, impacting everything from agricultural output to school attendance.