How to Choose Materials for New Road Construction

Though many people tend to take roads for granted, well-constructed and maintained streets and highways help connect people, enabling stronger economies and better access to goods and services.

When choosing materials for road construction, contractors must consider the type and number of vehicles that will travel on it, what kind of weather conditions it will face and how long it will take to complete road surfacing.

This article will cover some of the key types of road construction materials and discuss how to choose the best materials for an upcoming project.

Why Roads Need Different Types of Materials

Roadways are unique in a lot of different ways — they face different traffic loads, different types of vehicles and all kinds of environmental conditions. They also connect different communities with unique needs and goals.

The materials used to build the roads are likewise all very different. Some materials offer more strength and load-bearing capacity so they can withstand more wear before becoming damaged or deformed, and others might offer more resistance to heat, heavy rainfall or large ups and downs in ambient temperature.

For each new project, engineers and contractors must choose the material that best suits the conditions that will impact the road.

3 Key Types of Road Construction Materials

When choosing which material to use for a road, contractors need to consider the traffic volume and load, local environmental strains and the budget available for the project, as each material comes with different constraints on these factors.

1. Asphalt

Asphalt is a road material composed of aggregates bound with bitumen, popular partly because of its flexibility to be used in different conditions and its ease of installation — asphalt is well-suited when roads need to be constructed quickly and with minimal disruption. 

Asphalt is one material best-suited for suburban roads, because it can be used to build roads quickly and doesn’t see heavy or high volumes of traffic. Asphalt tends to handle cold weather well without cracking, and its dark color may even help to melt ice faster than other lighter-colored road materials. However, some formulations of asphalt can become soft and deform under high temperatures, so either a heat-resistant asphalt or concrete may be preferred in areas with extreme heat.

Characteristics:

Concrete

Because concrete roads are strong and durable, they’re often installed on roadways with expected heavy traffic. Concrete roads are generally expected to last well, though upfront building costs might be higher than other materials. Concrete is made from cement, water and aggregate material.

Concrete is best suited to urban areas with high-traffic volumes, since it tends to last longer and require less disruptive maintenance throughout its lifespan.

Characteristics:

Gravel

Gravel roads are cost-effective and quick to install, but may need quite a lot of maintenance to fix potholes and to keep them from eroding. Gravel roads are made from a mixture of loose aggregates, which is spread over the road periodically.

Gravel is cost-effective and easy to install for rural or low-traffic roads, paths and driveways.

Characteristics:

Factors Affecting Road Longevity & Maintenance

The longevity of a road depends on climate conditions, traffic loads, construction quality and regular maintenance practices. Prioritizing these factors during planning can help significantly extend road life.

Climate Considerations

The location of the roadway is a significant factor in what materials it should be made of. For instance, both extreme cold and extreme heat can impact roadways. Areas that see both heat and cold need materials that can resist cracks in cold weather and the heat and humidity of summertime. For example, asphalt may withstand cold temperatures without cracking better than concrete, but can prove to be more susceptible to damage from de-icing chemicals.

Traffic Loads

Traffic volume is one of the key factors in deciding which road material to use. Traffic studies and data analyses can predict the amount and type of traffic that will use a roadway. In many cases, asphalt is used for moderate traffic areas like parking lots and side streets, while concrete is used for high-load areas like highways and expressways or on industrial roads where heavy vehicle traffic is common.

Maintenance Practices

How long any given roadway will last may depend in part on the level of maintenance that is planned or needed to keep it up. For instance, keeping a gravel road in good working order requires regular grading, while patching, striping and resurfacing are all regular needs for paved surfaces.

Additionally, some municipalities may have specific rules that dictate the types of material that can be used on infrastructure. Environmental, safety, and zoning regulations may all come into play. For instance, some regions may have strict emissions rules that require contractors to use recycled asphalt or low-emission concrete, or safety rules that ask for roadways with adequate road traction during bad weather.

Tools to Help Choose Road Materials

There are many factors at play in selecting the type of materials to use in road construction, but there are some tools to help decide which material might be optimal in a given situation. For example, the Kentucky Transportation Center released a document demonstrating a comparison of expected output and maintenance costs to help municipalities choose when to pave a gravel road. The Upper Great Plains Transportation Institute provides a calculator to help select between road construction materials.

Data analysis from road usage and maintenance, coupled with a team effort between construction stakeholders, can help make the best possible decision for the next steps for road construction.

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Road Construction Materials: Consider All the Factors

Information will be key in selecting road materials. Designers and contractors can use statistics about past use, future goals and maintenance constraints to help decide what might work best in a given situation. Open communication between the project owner, designer and contractor can lead to greater collaboration and the best possible outcomes for the roadways that impact users every day. By keeping the lines of communication open and considering factors like traffic, climate and budget, general contractors can choose the most appropriate road material for successful and sustainable road projects.

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