A well-constructed asphalt driveway is extremely tough and can last for decades, but any asphalt structure becomes more vulnerable to damage as it ages. If your asphalt driveway is getting on in years, it may start to show a specific type of age-related damage known as block cracking.
Block cracking is particularly common during hot weather. With the current summer heatwave showing no signs of letting up, your cracked driveway may be in dire need of professional repairs.
What Is Block Cracking?
Block cracking is a specific type of surface cracking that can affect any form of asphalt paving, including residential driveways. It consists of an interconnected series of cracks that run both along and across your driveway, forming roughly rectangular 'blocks' of undamaged asphalt between the cracks.
In rare cases, block cracking can appear shortly after an asphalt driveway is laid because of installation errors. However, in most cases, block cracking strikes after many years of use.
Over time, the sticky, viscous binders that hold your asphalt driveway together become hard, brittle, and inflexible. Hardened binders can no longer hold the asphalt together.
Block cracking certainly looks bad, but aesthetics are the least of your worries. The cracks created by block cracking allow moisture and rainwater to seep deep into the interior of your asphalt. Moisture infiltration can cause even more damage to the asphalt binders, and may also erode the soil and aggregates beneath the driveway, causing potholes to form.
Without professional repairs, block cracking will become steadily worse over time, and some cracks may grow several inches wide. At this point, the asphalt driveway is practically unusable, and may have to be completely replaced.
How Does Summer Heat Cause Block Cracking?
Asphalt driveways and paving expand as they absorb heat during the day, and contract again at night when cooler temperatures return. The higher the temperature, the more the asphalt expands, so extreme heatwaves can cause considerable expansion.
The binders in relatively fresh asphalt are flexible enough to withstand this expansion and contraction cycle, but old, brittle binders cannot. During heatwaves like the one many Americans are currently experiencing, significant asphalt expansion can quite literally pull an older driveway apart, causing extensive block cracking with wide, deep cracks.
What Should You Do If Your Asphalt Driveway Is Block Cracking?
If you notice the distinctive signs of block cracking on the surface of your asphalt driveway, you should call in a professional residential paving repair service as soon as possible. Waiting will only allow the cracks to become wider, deeper, and more difficult to repair. Your paving repair service will inspect the parts of your driveway that are block cracking, and check the asphalt inside the cracks for signs of moisture damage.
If the block cracking is relatively minor, it can usually be repaired using crack sealants. These sealants are made from a specialized type of rubberized asphalt that is more flexible than regular asphalt. High quality crack seals can last for many years.
If the block cracking is more severe, your driveway may need to be overlaid with a layer of fresh asphalt. This is more expensive than crack sealing, but much cheaper than digging up and replacing the whole driveway, and the overlay is very long-lasting.