Hairline Cracks in Concrete Driveway: A Quick Guide
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What are Hairline Cracks in Concrete Driveway?
Hairline cracks in a concrete driveway are very small, about 0.003 inches in width and can be very shallow. In comparison, human hair is one-thousandth of an inch, or 0.001 inch wide.
In other words, hairline cracks in an exposed concrete surface have widths that are barely perceptible.
Hairline cracks in concrete are typically observed in freshly placed concrete and are caused by plastic shrinkage, which is the rapid depletion of moisture from the fresh concrete within its plastic state.
Causes of Hairline Cracks in Concrete Driveway
Hairline cracks in concrete driveway are typically caused either by shrinkage during curing, settling of the ground or minor structural movements.
1. Shrinkage during Curing:
Hairline cracks in concrete primarily stem from shrinkage during the curing process. Swift moisture loss can lead to tiny fissures. This is one of the reasons control of the concrete curing process is so important.
Certain environmental factors can exacerbate hairline crack formation as they directly impact the curing process. These include temperature fluctuations, humidity levels, and wind speed.
Extreme environmental conditions can accelerate evaporation and result in hairline cracks in concrete.
Unusual water absorption by the sub-grade, bleeding, sedimentation, and alkali-aggregate reactions are some other reasons for high levels of hairline cracks in concrete driveway.
2. Settling of the Ground:
Over time, the ground beneath the driveway may settle unevenly, causing the concrete to shift and crack.
Usually ground movements are large enough to cause concrete cracks that are far wider than what would be termed as hairline cracks.
However, very minor ground movements, caused by imperceptible tremors, can result in hairline cracks in concrete driveway.
3. Minor Structural Movements:
Even small movements in the surrounding environment can contribute to hairline cracks. This includes factors like nearby tree roots exerting pressure on the concrete from below, changes in temperature or freeze-thaw cycles, causing stress.
Repairing Hairline Cracks in Concrete Driveway
Hairline cracks in concrete driveways do not pose any structural concern. These cracks are superficial and do not compromise the integrity or load-bearing capacity of the driveway.
Therefore, repairing hairline cracks for structural reasons is unnecessary. It does not provide any tangible benefits in terms of driveway stability or durability.
Concrete is inherently prone to cracking due to factors like shrinkage during curing, settling of the ground, and minor structural movements. Hairline cracks are purely cosmetic in nature and barely visible in a driveway.
You may still choose to cover up hairline cracks in your concrete driveway, purely for aesthetic reasons.
Concrete crack sealants do not work on hairline cracks as they usually can not penetrate into the extremely tiny cracks due to surface tension. Moreover, they will follow the crack lines and actually highlight the hairline cracks rather than hide them.
As hairline cracks on concrete driveway are likely to be widespread, it is better to use a product that covers the entire driveway, thereby camouflaging the hairline cracks. In my opinion you have three options that will work.
1. Micro Topping
Micro topping is a thin overlay system applied to existing concrete surfaces. It consists of a special blend of cement, polymers, and other additives that create a smooth and durable surface.
Unlike traditional concrete mixes, micro topping is significantly thinner, ranging from 1/16th to 1/8th inch in thickness. This unique composition allows it to bond securely with the existing concrete, effectively covering up imperfections and providing a fresh, modern look.
I recommend using Surecrete Microtek One Coat Microcement Overlay for Concrete. SureCrete’s Microtek is a single component, self-bonding, cement-based, extremely thin overlay for indoor and outdoor concrete surfaces.
Microtek is designed to yield an exceptionally smooth tight-troweled finish that can really enhance the looks of your concrete driveway. The product comes in white but feel free to give it any color you like by adding Surecrete SC Color.
This micro topping is ready to use, just add water, Surecrete SC Color, mix and apply with a trowel or sprayer.
2. Skim Coat
A skim coat concrete driveway overlay is a thin layer of specially formulated concrete or cementitious material that can be applied on top of an existing concrete surface. A skim coat concrete driveway overlay will result in a significant improvement in the appearance of your driveway.
This thin layer serves multiple purposes:
- Smooths out minor imperfections
- Renews the overall driveway appearance
- Extends the concrete driveway lifespan.
RECOMMENDED PRODUCT
The Best Concrete Resurfacer for Your Driveway, Patio, Walkway, etc.
The best DIY Concrete Resurfacer for small or even slightly larger exterior concrete surfaces such as driveways, concrete walks, patios, etc. is Sakrete Flo-Coat Concrete Resurfacer. The product is a polymer-modified, sand and cement resurfacing material requiring only the addition of clean water.
Sakrete Flo-Coat Concrete Resurfacer
Can be applied in a flowable consistency using a squeegee or in a stiffer consistency using a trowel. Designed for applications from ¼ in. (6 mm) down to ⅛ in. (3 mm).
With proper surface preparation, the overlay can be applied efficiently, minimizing disruption to your daily routine. For a standard residential driveway, you will be able to use your newly transformed driveway in a matter of days.
3. Rubber Coating
Rubber coating for concrete driveways is the application of a coat or two of a rubber-based material onto the existing old concrete surface to rejuvenate its looks, functionality and durability.
The rubber coating is composed of a blend of rubber (often synthetic & recycled) particles, pigments, binding agents and additives.
RECOMMENDED PRODUCT
The Best Liquid Rubber Coating & Sealant for Your Driveway, Patio, Walkway, etc.
The best DIY Liquid Rubber Coating & Sealant for small or even slightly larger exterior concrete surfaces such as driveways, concrete walks, patios, etc. is Liquid Rubber Color Sealant. The product is a polymer-modified, sand and cement resurfacing material requiring only the addition of clean water.
- UV stable, water-based flexible coating.
- Application is similar to painting, but requires heavy coats to build the waterproof membrane.
- For use on various materials and types of projects, with eight color options.
With a rubber-coated driveway, you can have peace of mind knowing that accidents or injuries due to slippery surfaces are significantly reduced.
Thank you very much for reading this post. I do hope you found it informative and helpful.