Sealcoating is a cost-effective way to extend the life of your asphalt driveway or parking lot. It restores faded asphalt to its jet black appearance and prevents weather damage and oxidation.
First, your pavement needs to be cleaned and repaired prior to the sealing process. It should be free of dirt, weeds, fine cracks and oil spots. For more information, click the link https://www.rochesternysealcoating.com/ provided to proceed.
Coal Tar
Coal tar is a thick black protective substance used on many asphalt parking lots, driveways, and playgrounds. While it helps seal and preserve these surfaces, coal tar also releases chemicals into the environment that can be harmful to human health and wildlife. These chemicals are called polycyclic aromatic hydrocarbons (PAHs).
PAHs are a group of chemical compounds that contain carbon and form when materials such as coal, gasoline, diesel fuel, or tar are burned. Coal tar can release up to 202,000 times more PAHs than uncoated asphalt. These chemicals have been known to cause cancer, mutations, birth defects, or death in humans and other animals. The chemicals can also be photoactivated, meaning that their toxicity is increased by exposure to sunlight.
The chemicals in coal tar can be inhaled, swallowed, or absorbed through the skin. Children who live next to parking lots coated with tar-based sealants ingest 14 times more PAHs than those who live near uncoated pavement, according to one study. As the dust from coal tar spreads, it can also contaminate soil and water. PAHs can persist in the environment for months, years, or even longer.
Some communities have banned the use of coal tar sealcoat, and others are considering doing so. A ban in Austin, Texas, was prompted by the discovery that coal tar-sealer is the leading contributor to the upward trend of PAH levels in the city’s lakes. Sediment cores taken from Lady Bird Lake, the city’s primary receiving water body, before and after the coal tar sealcoat ban showed a 58 percent decrease in PAH levels.
Although a number of coal-tar-based products are still on the market, many professional sealcoating contractors have moved away from these substances and offer petroleum asphalt-based options instead. These alternatives are much safer and do not have the same environmental impact as coal tar-based products.
Asphalt sealants require proper mix design and application techniques in order to perform properly. This involves strict adherence to the manufacturer’s guidelines regarding dilution and weather conditions. Excessive dilution or excessive amounts of sand in the mix design will greatly reduce the performance of these products.
Tar-Based
A coal tar-based sealcoat is the black, viscous liquid that’s sprayed or painted on many asphalt parking lots, driveways and playgrounds to protect and beautify the underlying asphalt. These sealcoats contain as much as 30 percent coal tar by weight. Unfortunately, they’re also not safe to use for a number of reasons.
When coal-tar-based sealcoat dries, it flakes into small particles that can easily wash into stormwater or be blown around by the wind and stick to tires, which then transport them into the air where they can be breathed in. These small particles can also vaporize and contaminate the surrounding environment. When this happens, it can increase the levels of polycyclic aromatic hydrocarbons (PAHs) found in water. PAHs are a major environmental concern because they can cause cancer, mutations or birth defects in fish, plants and animals.
Because of their toxicity and environmental impact, many municipal and state governments have banned the use of coal-tar-based sealcoats. However, for property managers who need to perform a high-quality and cost-effective pavement sealcoating project, there are still options that are safer for the environment and for people.
Refined tar-based sealers (RTS) are safer for people, pets and the environment. RTS is made from a selectively refined fraction of crude coke oven tar, a byproduct of steel making. The tar is processed into base materials, which are then blended with rubbers and polymers to make the RTS. All of this is done in a controlled factory setting, so no on-site blending is required.
In addition to the health and safety benefits of RTS, it’s also the best choice for environmentally responsible sealcoating projects. It can be applied in wet weather and is less expensive than asphalt emulsions. It can also be mixed with up to 50 percent by volume of recycled rubber/polymer content for additional sustainability and performance.
Using recycled rubber/polymer material in the sealcoat increases its life and improves its durability. It also reduces the amount of petroleum-based products that are used in the coating. Additionally, RTS is formulated to meet specific project requirements with respect to the specified coverage rates (squares feet per gallon) and other specifications arrived at by the ordering agency.
Latex
The sealcoat material used in the protection and preservation of off-street asphalt surfaces; home driveways, airport runways, parking lots etc. is usually a refined coal tar or asphalt emulsion base coated with sand and other aggregates. Many sealcoatings contain special additives to improve the performance of the product in regards to durability, flexibility, fuel resistance etc. Many of these additives are based on latex polymers.
These types of additives serve a multitude of purposes; from thickening (to re-constitute the viscosity of mixes thinned by excessive amounts of water) to altering the sand suspension or increasing the fluidity of the mix to make it easier to apply, storage and handling. They also serve to enhance the properties like cold temperature flexibility, toughness and tack reduction at higher temperatures, increase the fuel resistance and the chemical resistance of the sealcoating.
While there is a plethora of different additives and the various chemistries that they have to offer, the selection must be made with proper understanding of their basic properties and overall contribution to the overall sealcoating longevity. Adding additives that do not fully compliment and boost the properties of the sealcoat will actually detract from its overall longevity.
A Typical RTS Sealcoat Mix design contains the main liquid binder (RTS), which is the thick black liquid byproduct of the distillation of bituminous coal. This is blended with an aggregate such as sand or black beauty and a special additive to produce a high-performance coating that resists damage caused by weathering, oils, chemicals and jet fuels.
Depending on the mix design, the addition of sand/aggregates will improve the skid resistance, produce uniform texture and fill minor surface defects. It will also allow for the use of a lower concentration of sealer thereby improving the fuel resistance of the finished coat.
Some of the more popular additives are acrylates, urethanes and polyvinyl acetates. These additives have been found to provide a good balance between sand/aggregate suspension, quick drying and thicknessing. However, they do not have the improved resistant qualities to fuels (petroleum and diesel), de-icing salts, chemicals and UV radiation that tar based additives have.
Acrylic
Acrylic sealers are a great option for concrete, masonry, and brick surfaces that require a durable coating. They form a substantive film that protects the surface from acids, oils, salts, food stains, and UV rays. They beautify decorative concrete, enhancing the colors while curing and sealing the material for years with a breathable film.
Water-based acrylic sealers are safer and less toxic than solvent-based alternatives, which release harmful fumes. They are ideal for applications where the use of a caulk gun is preferred, as the application method allows you to control the amount of sealer being applied and create uniform lines. For best results, the surface should be clean and free of dirt or debris before applying the sealer. Masking tape along the edges of the area will help you maintain a straight line when applying the sealer.
When used as directed, acrylic sealers can last up to three times longer than other asphalt seal coat options. They resist oil stains and debris like gasoline spills and antifreeze, helping to keep your parking lot looking clean and well-maintained. They also provide a barrier against moisture that can lead to the deterioration of the surface, causing cracking and peeling.
The longevity of a sealant depends on proper maintenance and routine care as well as the quality of the product. The most common causes of sealer degradation are exposure to sunlight, oxygen, and moisture. Higher-quality products feature UV-stable resins that prevent the yellowing of the membrane.
In addition to ensuring that your sealant is of a good quality, it’s important to follow the manufacturer’s recommendations for preparation and application. It’s important to clean and prep the surface before applying the sealant, using a broom or stiff brush to remove any loose debris or dirt. Afterward, it’s a good idea to use a high-quality pressure washer to ensure the surface is completely clean and free of any residual chemicals or dirt.
If you have a sealed surface that is showing signs of wear and tear, it’s a good idea to contact a professional asphalt and concrete sealcoating contractor for advice and a recommendation. An experienced team can diagnose your gravel or asphalt surface and recommend the correct sealcoating materials for maximum performance.
