Asphalt is often the default material used when it comes to laying roads. It has remained in use for centuries and will likely remain relevant for the foreseeable future. How long does it take to complete asphalt roads?
It can take anywhere between two weeks and a year or more to lay asphalt roads depending on the scope and the length of the road. The laying process is also only a part of the wider road construction project. Therefore, the exact length of time is influenced by the duration of each stage. However, once laid, asphalt can set within 72 hours and fully cure in 6-12 months.
The rest of the article will cover factors that determine the length of time spent laying asphalt roads. You’ll also see factors that influence asphalt cure time and why the material is very popular in road construction.
Factors That Affect the Duration of Asphalt Road Construction
There are different stages to road construction. Each of them contributes to the overall length of time it would take to complete an asphalt road construction project. The stages include the following:
The first step in laying any road (including asphalt) is planning.
Depending on the project’s scope, dozens of industry experts and stakeholders will come together at this stage. During the meetings, they’ll decide the design and type of road to be constructed. To settle on a design, they pay attention to the user base and the traffic expected on the road.
The planning stage for straightforward roads will take less time than one that’ll incorporate complex structures such as overpasses, bridges, and tunnels. While planning on the former can be completed in a few months, planning on the latter can take years.
Stakeholders in the project also have to look at how the road will affect the environment, construction safety, and nearness to raw materials and manpower for the project. At the end of the deliberations, they’ll arrive at a budget. The entities laying the road will also need to seek public opinion on the construction.
When all bases have been covered, contractors can submit bids for the project. As soon as a contractor is selected, the construction will start with equipment moving to the site.
Site Excavation and Clearing
The stretch where the road has to be laid needs to be cleared of all vegetation first. So, trees and shrubs have to be cleared away. Excavation vehicles will dig up and remove the rocks and stones as well at this stage. Basins, fences, and ditches will be installed along the road to keep the cleared area from eroding.
The road starts to come together at this point. Bulldozers and excavation machinery will mount dirt and soil along the road. Once that’s done, the surface can be leveled and smoothed out by graders. Ditches and drains containing large concrete pipes are installed at this stage to ensure the road won’t get flooded by rainwater, sewage, etc.
Leveling and Grading
The construction workers have to prepare the surface by leveling it to meet the plans agreed on during the planning stage. This stage involves manual labor and the use of graders and other grading plant machinery. You should stabilize the grading with limestone or concrete to make it durable.
Laying of Aggregate
The aggregate base features crushed gravel and stone. It’s spread out evenly across a road’s surface. In cities, a pavement curb and the gutter gets constructed after the gravel is placed on the surface. Once the aggregate is laid, the road is fine graded a second time. The second grading is important to give the road a durable foundation.
Laying of Asphalt
Pouring asphalt is the last stage of the major road construction work. The material is a mix of aggregates and bitumen. The construction engineer(s) determines the mix ratio before the asphalt is produced. For heavy traffic roads, four layers of asphalt may be laid on one road.
Once the mix is ready, trucks transport the hot material to the construction site where it’s poured. The last asphalt layer is poured after the sidewalks and gutters have been completed.
The length of time spent on each of the stages before laying asphalt will vary from one project to another and across different jurisdictions. However, the asphalt laying stage is the least time-consuming part of the process.
How Long Does It Take for Asphalt To Set and Cure?
There’s no fixed timeline for asphalt to set and cure. However, most asphalt construction will set within 72 hours and then cure fully before 12 months.
Two main factors determine the length of time it’ll take asphalt to set and cure. They include the following:
- Environmental conditions. Environmental conditions play an important part in how long it would take asphalt to set and cure. Factors such as heat, sunlight, wind, and outside humidity all influence the setting and curing process. Asphalt roads laid in hot climates will require a longer time than one laid in cooler climes.
- Material thickness. The thickness of the asphalt laid down can also affect the length of the setting and curing time. As stated above, some construction features four layers of asphalt. Such projects will take longer to set and cure than those featuring two layers.
Once the asphalt has set, it can take vehicular movement without damage. However, it’ll remain pliable for another 6-12 months—which is the length of time it’ll take to cure.
Why Is Asphalt a Popular Choice in Road Construction?
Asphalt has become the popular and leading choice of road pavement construction material for a range of reasons, including longevity, cost-effectiveness, and eco-friendliness.
- Longevity. Asphalt roads can last decades if properly designed and constructed. In that time, it’ll require regular maintenance, but the core structure can last a long time. The advantage of such longevity is that projects won’t need to be redone in the short term, and there will be minimal disruption of vehicular traffic on the road.
- Smoothness. Asphalt surfaces are smooth, reducing wear and, by extension, the need for repairs. Smooth roads are also good for the vehicles plying the route. Drivers will experience reduced drag on vehicles and fuel consumption.
- Faster project timeline. Using asphalt in construction significantly reduces the overall construction time. Once the grading is completed, the asphalt laying part of the project takes the least amount of time. Once it’s cooled and set, contractors can open the road to motorists.
- Cost-effectiveness. Asphalt is a cost-efficient material for road construction. It’s one of the cheapest materials in terms of raw costs and construction labor demands.
- Durability. Asphalt can hold up in a wide range of environmental conditions. That’s why it’s the road construction product of choice in both the temperate and tropical regions of the world.
- User safety. The smooth finish of asphalt keeps road users safe because it provides skid resistance and makes the formation of ice and snow on a road surface more difficult.
- Eco-friendliness. Asphalt is good for the environment because it’s made of recycled materials. Completed roads can also be dug up and reused when necessary.
Asphalt is an excellent material for road construction. However, it’s impossible to construct a road with asphalt alone. With other stages necessary to ensure a durable road, it’s hard to put a timeline to the construction duration. While it’s possible to complete quick projects in two weeks, more demanding and elaborate construction can take years.
The construction engineer responsible for the project is in the best position to give a definitive timeline.