Uneven drying, shrinkage and temperature changes can all cause fractures in your slab. To avoid water seepage and further damage, it's critical to seal any cracks that develop.
Moist curing is a common method of concrete curing. It involves wetting the concrete slab often with water (5-7 times per day) for the first 7 days. This method ensures your concrete slab will be extremely strong and durable, because it allows the moisture to evaporate slowly, preventing cracks and shrinks.
As the slab loses moisture while curing it gets a bit smaller. As the concrete shrinks, the slab could crack in order to relieve tension. Shrinkage cracks are common and can occur as early as a few hours after the slab has been poured and finished. Usually they are not a threat to the structure.
Concrete driveways are a common part of the exterior of a home. They provide an even surface for vehicles and can be an integral part of providing access to a home. However, concrete will almost always crack and this is often times just part of the curing process.
Poured correctly and well-maintained, asphalt pavement can last for nearly 20 years. However, it still requires steady maintenance over time. A driveway should be resealed about every 3 years and often, asphalt driveway cracks develop and need to be repaired more frequently than that.
While you may see small driveway cracks as nothing important, they can be the first sign that you may have foundation issues.
The hardening, or curing, continues as long as moisture remains in the concrete. If too much water is lost from the concrete through evaporation, the hardening process slows down or ceases.
As the shrinkage begins, the concrete will crack where it is the weakest. Cracking typically starts within 12 hours of the finishing process. Weather conditions will slow or accelerate it. Shrinkage cracking is typically planned for and handled with control joints.
In residential concrete, 4 inches is the minimum thickness for walkways and patios. Garage slabs and driveways should be 5 to 6 inches thick if any heavy truck traffic is anticipated, otherwise 4 inches is adequate.
How long does four to six inches of concrete take to cure? As stated previously, concrete takes approximately 26-30 days to reach its full strength. If the concrete is professionally poured and floated, the curing process should be sound and ensure proper hardening of the concrete base.
Epoxy sealers like Rust-Oleum Concrete Patch & Repair are waterproof products that are extremely strong and durable. These are good for cracks in foundation or basement walls, as well as horizontal cracks on concrete pavement or driveways.
For use on Driveways, Parking Lots, Streets, Highways, and Airport Runways. Flex-A-Fill® is a hot-applied polymer modified asphalt sealant used to seal cracks in asphalt concrete or Portland cement concrete pavements.
Hot weather is defined as ambient temperatures above 90 °F, including low humidity and high wind speeds. In conditions hotter than 77 °F, the water used to hydrate and cure the cement can evaporate, increasing the concrete's temperature and presenting problems such as weakness, shrinkage, and cracking.
Properly curing your concrete improves strength, durability, water tightness, and resistance for many years. The first 7 days after installation you should spray the slab with water 5-10 times per day, or as often as possible. Once the concrete is poured the curing process begins immediately.
The best way to cure is with continual and consistent watering of the concrete. The concrete must be saturated 5-10 times per day for at least the first 7 days, but ideally 28 days to reach its full effective strength.
It is generally recommended that you wait at least a week before driving on the surface with a passenger vehicle. Even then, the slower curing areas, such as the edges, will not be as hard as they need to be. For this reason, you'll want to be careful until the concrete is fully cured.
Concrete driveways can crack for many reasons. Repeated freezing and thawing, heavy loads, tree roots and even shifts in the ground can cause damage. When you learn how to repair cracks in a concrete driveway, you may be able to stop them before they lead to bigger problems.
Too much water can wash away the soil supporting your concrete. Too little and it can cause the soil to shrink. And when water freezes and thaws over and over and over and over again, it can cause the surface of your concrete driveway to crack, pit, and crumble. Think of your driveway as a giant sponge.
The older your asphalt is, the more likely it is to develop cracks. As it gets further along, the material begins to degrade and loses its natural ability to withstand your surface's daily pressures. So when that significant rainfall or that freeze and thaw cycle comes, older driveways are more likely to suffer damage.
According to HomeAdvisor, a driveway repair professional will charge as little as $300 to fix minor concrete driveway cracks, but most homeowners can do the job on their own with a rubber or synthetic crack filler. This costs about $0.10 to $0.15 per linear foot—but watch out if cracks are larger than 1/8 of an inch.
Cracks up to ¼ inch in width can be filled with sealant.
Cracks of this nature may never get any larger, but water can seep into them, freeze, and expand, causing the cracks to widen, so it's a good idea to seal them with the flexible Advanced Polymer Concrete Crack Sealant from Quikrete.
Concrete Repair Options for a Cracked Driveway
Slabjacking, or mudjacking, involves drilling small holes in the concrete and injecting a cement slurry mixture. This works to fill the soil voids underneath – the reason for the cracks – and lift the slab back up into proper position.
Although the terms cement and concrete often are used interchangeably, cement is actually an ingredient of concrete. Concrete is a mixture of aggregates and paste. The aggregates are sand and gravel or crushed stone; the paste is water and portland cement.