At what temperature can you lay asphalt? When scheduling asphalt installation or repairs, it’s vital that homeowners consider outside temperatures, ground temperatures, and even humidity, rainfall, and other weather conditions! Weather extremes interfere with asphalt’s curing process, and you don’t want to trap rainwater underneath new asphalt or install asphalt on overly moist soil.
While you don’t need to wait for perfect weather to fill potholes or schedule asphalt installation, you might consider at what temperature you can lay asphalt and what extremes to avoid. Check out these 7 pro tips on temperature and other weather requirements when laying asphalt, and don’t hesitate to discuss your options with an asphalt contractor near you as needed.
To know at what temperature you can lay asphalt, first note that asphalt is mixed in a drum, typically at 280 degrees Fahrenheit on average, and then installed while still warm. This is done because asphalt is a mixture of aggregates or crushed stone, a petroleum-based bitumen or binders, and sand.
Heat keeps that bitumen pliable so that asphalt can be spread over a surface and then pressed or compacted into place; as it dries, that mixture hardens and becomes the dense pavement you drive over! Overly cold outside temperatures allow asphalt to harden too quickly, while cold or frozen soil doesn’t allow asphalt to be pressed or rolled into place as needed.
To keep asphalt soft and allow for proper rolling and compacting, outside and ground temperatures should be at least 50 degrees Fahrenheit. During colder months, most asphalt installation contractors will use infrared thermometers to read temperatures properly, as an everyday exterior thermometer doesn’t typically provide the accurate reading needed for proper asphalt installation.
While asphalt must stay warm and pliable during installation, outside temperatures can get too hot so that asphalt doesn’t start to set and cure as it should once installed. To keep asphalt in good condition and allow it to start curing once poured, ambient temperatures should be below 90 degrees Fahrenheit.
Asphalt can also melt once outdoor temperatures reach 120 degrees Fahrenheit; while this extreme heat is rare, keep in mind that asphalt itself holds heat! For proper viscosity, the asphalt itself should remain at 250-325 degrees Fahrenheit. If your material gets too warm and doesn’t hold its binding, it’s best to put off your installation or repairs until the material can cool as needed.
Asphalt starts to cure once it cools, typically at about 220 degrees Fahrenheit; once it reaches 185 degrees, asphalt becomes too stiff and dense for proper compaction. Ambient and ground temperatures are important to remember when laying asphalt or making pothole repairs, but high winds and an overly dry atmosphere can also cool asphalt prematurely so that it becomes too cold to pour and compact.
Asphalt also begins to cool once applied, which is why skilled asphalt installers begin compacting or rolling asphalt quickly after it’s poured! If you’re a homeowner considering DIY asphalt installation, ensure you work in small sections so you can pour and then compact asphalt quickly, before it cools and begins to set or harden.
The short answer is no, you should not lay asphalt when it rains. Asphalt’s bitumen or binders are petroleum or oil based, and of course oil and water don’t mix! Rain, falling snow, and even excess humidity can allow those binders to break away from asphalt’s aggregate base so that the material begins to crumble or fall apart.
Even if you do manage to lay and compact asphalt in rainy weather, that material might then crack or split, and potholes will form sooner rather than later. Oil in that bitumen might also rise to the surface so that your new asphalt starts to show stains and discoloration. That oily surface also increases the risk of spalling, or surface damage.
Asphalt also needs a solid, firm foundation under it so that it stays compacted and avoids splits, cracks, spalling, and potholes. Damp soil allows asphalt’s aggregate base to sink and the soil itself also begins to soften when it’s raining.
To keep that foundation or base in good condition, wait until the rain stops and the ground dries before new asphalt installation or repairs. If you notice potholes filling with water or overly damp aggregate or soil, dry out those areas before patching and filling.
Spring is the best time to lay asphalt! Seventy degrees Fahrenheit is typically the optimal temperature for installing asphalt, as this ensures ambient and ground temperatures are warm enough to keep asphalt soft and pliable for pouring and compacting.
This doesn’t mean that the first 70-degree day is right for installing asphalt, however, as springtime can mean fluctuating temperatures throughout much of the country! Wait until ground temperatures catch up to surrounding temperatures before scheduling your asphalt installation, which usually occurs in late spring.
High humidity can also mean too much moisture in asphalt, allowing it to break down. While warm summertime weather can keep asphalt soft and pliable, it can also mean too much humidity in the air!
For optimal ambient and ground temperatures, and proper humidity levels, avoid hot summer days for scheduling asphalt installation and especially if you live in humid climates. Instead, opt for late spring or early summer, or sometime in autumn, once outside temps and humidity levels begin to dip.
New asphalt takes a full 6 to 12 months to cure or set completely. This doesn’t mean you need to avoid your parking lot or driveway during this time, however! Avoid driving on new asphalt for a full three days and up to a week in hotter temperatures; after that, you can use your new pavement for standard vehicle traffic even as the material continues to cure.
During the first year after new asphalt installation, avoid parking in the same spot repeatedly. A vehicle’s tires put concentrated weight on the pavement; parking in the same spot repeatedly risks soft spots and damage to fresh asphalt not yet cured completely.
It’s also vital to avoid parking on the edges of asphalt during the curing process, as edges are often especially weak while asphalt sets. Moving tires sideways while a vehicle is not in motion also puts pressure on fresh asphalt and can cause potholes and spalling.
If you must park a heavy vehicle on your new asphalt, including a commercial truck, motor home, or trailer, set down some plywood! Plywood helps disperse the weight of vehicle tires, avoiding indentations and resultant damage to the pavement.
One way to speed up your property’s asphalt cure is to keep it cool, as colder temperatures help asphalt harden and set, as said. While you don’t want to dump ice or use a freezing chemical on asphalt and risk it cracking and breaking, hosing your new pavement is an excellent way for the blacktop to cool and cure faster than average.
For small patches, you can also use a hairdryer on the cool setting! Use it for several minutes and ensure you concentrate the air on the middle of the patch, where it’s often the warmest and takes the longest to set and cure.
Commercial grade paint dryers can also help dry the bitumen or binders in asphalt, speeding up the curing process. Ensure you follow instructions for this equipment so you don’t damage your new asphalt, and remember that you still want to use caution when it comes to driving over freshly installed blacktop.
Asphalt is heated during its composition to keep it pliable and easy to spread, as said. However, the dark color of asphalt and its dense nature allows it to hold heat so that it’s dangerously warm during the installation process. As asphalt is spread, it releases some of that heat, which is why it’s often best to leave this work to the pros; even getting too close to asphalt can mean burns, sinus irritations, and other hazards.
The terms “blacktop” and “asphalt” are often used interchangeably; however, blacktop technically refers to an asphalt mixture with a higher concentration of crushed stone. That stone gives pavement a shinier appearance as well as added traction.
Playgrounds, sidewalks, basketball and tennis courts, and other such areas are often paved with blacktop rather than asphalt, to reduce skidding and sliding during play and to provide a safer surface for pedestrian traffic. Heavy vehicle traffic might dislodge those added stones, so blacktop is typically only used for roadways with light traffic versus standard city roads and highways.
If you’re considering a blacktop installation rather than asphalt, note that the two both need the right ambient and ground temperatures to lay and then set properly. You might ask your paving contractor at what temperature you can lay asphalt as well as blacktop, and he or she can advise on the best choice for your property and outside weather conditions.
This information was proudly presented by the pros here at Dallas Asphalt Paving. If you have more questions about the right temperature to lay asphalt or are in the market for high-quality asphalt installation and asphalt paving in the Dallas area, call us today! We offer FREE quotes and no-hassle, no-obligation appointments, and stand behind all our work with a full guarantee you can trust!