How Long Does Asphalt Take to Dry

An important consideration when paving is how long it takes for the asphalt to dry. This affects the quality of the pavement, the cost of the project, and the time of completion. To help you learn more about this process, our team at U.S. Pave has put together a short but informative guide.

Importance of Asphalt Drying

Asphalt drying involves the evaporation of moisture from the asphalt mixture to form a solid and compact surface. This can take two to three days on average, but the timeframe may change depending on several factors. Drying is different from curing, which is when the mixture’s molecules form stronger bonds that result in a fully hardened material. This usually has a timeframe of six to 12 months.

The proper drying of asphalt ensures the longevity and durability of the pavement. It forms a smooth and safe driving surface that can withstand heavy traffic and harsh weather conditions. Additionally, a properly dried surface reduces the risk of cracking and other types of damage that may occur over time.

Factors Affecting Asphalt Drying Time

These are some of the factors that can influence the time it takes for asphalt mixture to dry enough for use:

Weather Conditions

The best time for laying asphalt is usually in spring and the beginning of summer, when the air is dry and warm. If the weather is too cold, the mixture may harden too quickly, making it difficult to work with and causing irregularities in the pavement. If the temperature is too hot, the asphalt may dry too quickly, leading to cracking, or it may soften, which can delay both the drying and curing processes.

Temperature

In general, higher temperatures cause the mixture to dry faster. This is because warm temperatures make it easier for moisture to evaporate. However, it’s important to note that extremely hot temperatures can also have an adverse effect on the asphalt and drying process.

Humidity

When it comes to humidity, higher levels can slow down the process because there’s more moisture in the air, which inhibits evaporation. Conversely, low humidity allows for better absorption of moisture from the asphalt, resulting in a faster drying time. This is one of the reasons why asphalt tends to dry more quickly when rain is scarce and sunlight is abundant.

Thickness of Asphalt Layer

A thicker layer of asphalt requires more time to dry. There’s more moisture within that needs to evaporate, and more heat is also necessary to reach the desired temperature for drying. That’s why residential driveways that are usually paved with 2 to 3 inches of asphalt typically dry faster than heavy-duty roads with 4- to 7-inch asphalt layers.

Type of Asphalt Mix

Hot mix asphalt (HMA) is the most common type of asphalt used in paving projects, while cold mix asphalt (CMA) is typically utilized for repair jobs. Warm mix asphalt (WMA) is relatively new, but it’s gaining popularity because of its durability and versatility. Due to the temperature difference during application, HMA tends to dry more quickly than other types. CMA has a longer curing time than HMA and WMA, which may suggest a slower drying process than the two types.

Typical Drying Times for Asphalt Paving

Here’s a quick look at the typical drying times for various climates and the ensuing challenges contractors may face:

• Hot and dry: Asphalt can dry in two to four days in this weather. However, challenges can arise if the temperature becomes too high, such as the mixture softening or drying too fast, even before it’s laid.
• Cold and wet: It may take up to five days for asphalt to dry in this condition, or even a week or more if humidity is high. Moisture damage and a prolonged drying and curing process are the challenges contractors face when working with asphalt in this climate.
• Temperate: The drying time for asphalt in this climate falls within 24 to 48 hours on average because of its favorable conditions. Weather monitoring and temperature control are the challenges contractors face during the asphalt drying process in this instance.

Tips for Managing and Accelerating Asphalt Drying

Here are several tips you can follow to ensure that asphalt dries quickly and properly:

• Optimize environmental conditions: Low humidity, minimal precipitation, and moderate temperatures within the range of 50 to 85 degrees Fahrenheit are ideal for drying asphalt. It’s crucial that you consider the weather forecast and monitor the local conditions to ensure the drying process goes smoothly.
• Use additives or accelerators: Hydrated lime and liquid anti-strip agents are examples of additives that can be mixed into the asphalt to enhance its drying properties. Accelerators are chemicals that you can spray onto the surface of the pavement to expedite drying.
• Employ proper maintenance practices: Regular cleaning of the pavement can help remove standing water or debris that may hinder the drying time. Additionally, applying a sealcoat can protect the asphalt from moisture and accelerate drying.

Safety Precautions During Asphalt Drying

It’s essential that you follow these precautions during asphalt drying to ensure safety and prevent potential accidents:

• Traffic management: Temporary traffic control is necessary to minimize vehicle congestion, prevent accidents, and allow the pavement to dry and cure undisturbed. This may include implementing detours, installing barricades, and using signs to direct traffic.
• Proper signage: You should place clear and visible signs and markings around the area to alert drivers and pedestrians to the project. These also serve to notify them of potential hazards and changes in traffic patterns in the area.
• Protective measures for concerned parties: These include equipping workers with appropriate safety gear, ensuring adequate lighting in the area, and erecting safety barriers.  It also entails conducting safety inspections regularly to identify and address potential hazards.

Contact Us for Your Asphalt Paving Needs

Asphalt drying is a critical component of the paving process that numerous factors influence. It’s important that you consider these to determine not only the drying time but also when to begin a paving project. To ensure success, it’s a good idea to work with experienced and knowledgeable professionals. If you’re in Fort Lauderdale, Tampa, West Palm Beach, or other nearby areas, get in touch with us at U.S. Pave to learn more about how we can help you with your asphalt paving needs.

Asphalt Paving by Pam Broviak is licensed with CC BY-SA 2.0