How Long Does Asphalt Need to Dry Before Rain?

Asphalt is a popular material used for paving roads, driveways, and parking lots. It is a durable and long-lasting material that can withstand heavy traffic and harsh weather conditions. However, one of the most important factors to consider when laying asphalt is the weather. Rain can significantly affect the quality and durability of the asphalt, especially if it is not given enough time to dry.

solid surface

Table of Contents

How Long Does Asphalt Need to Dry Before Rain?

Freshly laid asphalt usually requires 48-96 hours to dry completely before it can be used safely by people and vehicles. Nonetheless, the drying time can differ based on factors such as temperature, humidity, and asphalt thickness. It is essential to keep in mind that even though the asphalt may seem dry enough to use, it may not be fully cured, hence it may still get damaged by severe weather conditions or heavy rainfall.

new asphalt driveway

Asphalt drying time before rain

It’s important to understand the drying time of asphalt before you pave your driveway. Simply, because rain can cause damage to it, resulting in cracks and other issues. In the following section, we’ll cover the different factors that influence the drying time of asphalt, the appropriate amount of time it should dry, and the potential consequences of getting it wet too soon.

Factors Affecting Asphalt Drying Time

Several factors can affect how long it takes for asphalt to dry. Temperature and humidity are two significant factors that impact the drying time. In general, asphalt dries faster in warm, dry weather conditions than in cool, humid conditions. Wind can also play a role in helping asphalt dry faster by removing moisture from the surface.

The thickness of the asphalt layer and the weight of traffic on the surface can also affect drying time. Thicker layers of asphalt take longer to dry, while heavy traffic can slow down the drying process.

Ideal Drying Time for Asphalt

Typically, it takes 24 hours for fresh asphalt to dry enough for you to walk or drive on it and only 2-3 hours for resurfaced asphalt to dry. However, the exact time may vary depending on the reasons covered above.

It’s important to note that drying time is not the same as curing time. Asphalt curing is the process of the asphalt hardening and reaching its maximum strength. It can take several months for asphalt to cure fully, depending on the weather conditions.

What Happens If Asphalt Gets Wet Too Soon?

Premature exposure to water can result in significant damage to asphalt surfaces. When rainwater infiltrates the asphalt, the oils, and binders may be washed away, causing it to weaken, crack, and develop an alligator-skin-like appearance known as alligatoring.

To protect the asphalt surface from rain, it’s usually a good idea to cover it with plastic or tarps. This covering can help prevent dirt, dust, and debris from getting onto the surface and help keep the surface dry. If the asphalt does get wet, it’s important to allow it to dry completely before using it.

curing process

Factors Affecting Asphalt Drying Time Sumarised

When it comes to drying time, there are several factors that can affect how long it takes to dry. These factors include temperature, humidity, sunlight, and wind.

Temperature

Temperature is one of the most significant factors affecting the drying time of asphalt. The hotter the temperature, the faster the asphalt will dry. On the other hand, if the temperature is too low, the asphalt may not dry at all. After reading an article from Limitless Golden Construction, the ideal temperature range for asphalt to dry is between 70°F to 90°F.

Humidity

Humidity is another factor. If the air is too humid, the moisture in the air can slow down the drying process. In general, asphalt dries best when the humidity is low. According to HowMonk, you should avoid laying asphalt on days when the humidity is above 90%.

Sunlight

Sunlight also plays a vital role. If the asphalt is exposed to direct sunlight, it will dry faster. However, if the asphalt is in the shade, it may take longer to dry. Nathan Paving covered this well where they explained that asphalt should be covered with a tarp or other material if it is exposed to rain or if it will be in the shade for an extended period of time.

Wind

Wind can also have an impact on the drying time of asphalt. If the wind is too strong, it can blow dust and debris onto the asphalt, which can slow down the drying process. On the other hand, if the wind is too light, it may not be able to help dry the asphalt.

humid temperature

Ideal Drying Time for Asphalt

When it comes to drying time for asphalt, the ideal period before rain depends on whether the asphalt is new or resurfaced. In general, it is best to avoid rain for at least 24 hours after the asphalt has been laid. However, the exact drying time may vary depending on weather conditions.

New Asphalt

New asphalt takes longer to dry than resurfaced asphalt. It typically takes anywhere from 48 to 96 hours for new asphalt to dry completely. However, if the weather is particularly humid or cold, it may take up to a week for the asphalt to cure. During this time, it is important to keep heavy vehicles and foot traffic off the surface.

Resurfaced Asphalt

Resurfaced asphalt, on the other hand, dries much faster than new asphalt. It typically takes only 2 to 3 hours for resurfaced asphalt to dry. After that, it is safe to walk and drive on the surface. However, it is still important to avoid heavy vehicles and foot traffic for at least 24 hours after the asphalt has been laid.

Here are some factors that can affect the drying time of resurfaced asphalt:

  • Thickness: The thicker the layer of asphalt, the longer it will take to dry.
  • Temperature: Higher temperatures can speed up the drying process, while lower temperatures can slow it down.
  • Humidity: High humidity can slow down the drying process, while low humidity can speed it up.
new pavement asphalt

What Happens If Asphalt Gets Wet Too Soon?

If asphalt gets wet too soon, it can lead to a number of problems that can affect its lifespan and stability.

One of the main problems that can occur when asphalt gets wet too soon is the formation of cracks. Water can seep into the asphalt and cause it to expand and contract, which can lead to cracks and the “alligatoring” effect. This can also happen if the asphalt is exposed to extreme heat or cold, which can cause it to contract and expand.

In addition to cracks, water can also damage the subsoil underneath the asphalt. This can lead to instability and a shorter lifespan for the pavement. Water can also wash away dirt, dust, debris, and solvents that are used in the asphalt paving process. This can weaken the asphalt and make it more susceptible to damage from traffic and parking.

To protect the asphalt from water damage, it is important to seal it properly. A protective coating can help to prevent water from seeping into the asphalt and causing damage. The sealer should be applied after the asphalt has hardened and cured properly. This can take anywhere from 48 to 72 hours, depending on the temperature and humidity.

UV damage and oxidation can also affect the lifespan of asphalt pavements. A protective coating can help to protect the asphalt from these factors as well. It is important to choose a reputable paving company that uses high-quality materials and provides proper maintenance and sealing services.

wet asphalt

Conclusion

Comprising of bitumen, aggregate, and sand, asphalt is a popular type of paving material. After being freshly laid, it usually takes anywhere from 48-96 hours to dry completely and become safe for people and vehicles to use. The actual drying time is subject to various factors, including temperature, humidity, and the thickness of the asphalt layer. It’s worth noting that although the asphalt may appear dry enough for use, it may not have fully cured yet, which could make it vulnerable to damage from heavy rainfall or heavy traffic. 

People also ask

Is it okay if it rains on fresh asphalt?

Rainfall on fresh asphalt is not ideal, particularly during the first 24 hours after it has been laid. The water from the rain can penetrate the surface of the asphalt, which may cause damage to the material and weaken its overall structure.

How long does it take asphalt to harden?

Asphalt hardening, or curing, is a gradual process that can take up to a year or more to complete. However, the majority of the curing typically occurs within the first few months after the asphalt has been laid. After the initial 1-3 day drying period, the asphalt will continue to cure and harden over time as it interacts with the air and sunlight.

Does asphalt dry faster than concrete?

Asphalt and concrete differ in how they dry and cure. Asphalt dries by evaporation of the liquid asphalt binder, while concrete cures through a chemical reaction called hydration. In general, asphalt dries much faster than concrete, usually taking only one to three days to dry enough for people and vehicles to use it safely. On the other hand, concrete takes several days to a week or more to cure fully.

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Oliver Wright
Oliver Wright

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