Sealcoating keeps damaging water from penetrating paved surfaces, prolonging their lifespan at a fraction of the cost of a new asphalt overlay. But it’s important to know what kind of sealcoat you need, and how to apply it. Contact Rochester NY Sealcoating for professional help.
Before workers can begin, they must clear the area of any visible debris or potholes. They also need to flash heat oil and gas stains to prevent them from bonding to the new surface.
Coal tar is the most common and oldest sealcoating material. It is the oily byproduct of distilling coal, and it is used as a base for most asphalt paving products. It is mixed with water and emulsifying agents to produce a tar emulsion. Coal tar is not as flexible as other sealcoat materials, but it is durable and provides excellent skid resistance. It is also easy to clean up, and it resists corrosion from salt and petroleum-based chemicals.
Asphalt emulsion is a relatively new product in the sealcoating industry, but it is growing rapidly as supplies of coal tar shrink. This type of sealcoat contains a blend of water and asphalt, with small amounts of coal tar added to improve its viscosity. The result is a smooth, black sealant that lasts for five to seven years, depending on weather conditions and maintenance. It is best suited for asphalt surfaces, but it can also be used on concrete and other surfaces.
Other tars are produced by heating wood at lower temperatures, usually in a tar kiln. This process is similar to the production of petroleum fuels, but it uses different chemical reactions. The resulting tar is usually a bituminous compound with the consistency of heavy oil. It is usually a bituminous black liquid, but it can also be a dark brown or greenish substance. It is a useful building material that is often combined with linseed oil to produce a paint called tar paint, which can be applied to wood surfaces and help them last longer.
Many homeowners buy tar from big-box stores and use it to do their own sealcoating. However, hiring a professional with the right equipment can save time and money in the long run. A local sealcoating company will know how to mix the right mixture of products for your driveway or parking lot, and they will have experience with repairing problems that are not visible to the untrained eye. They can also identify and prevent future issues, saving you money on costly repairs. In addition, they will provide you with the proper personal protective equipment (PPE) for your workers to protect them from harmful fumes and particles during application.
Asphalt emulsion
Asphalt emulsion is used for sealcoating asphalt surfaces, especially those that are not exposed to traffic and weather. It is typically applied using a mechanical asphalt sprayer. It is much thinner than coal tar and provides better slip resistance. It is not harmed by salts, oil, gasoline, or other petroleum-based products that would otherwise degrade Coal Tar. However, it does not provide the same level of resistance to the destructive effects of UV rays or extreme temperatures.
Asphalt Emulsion is produced by dispersing hot asphalt cement through water in a specialized emulsifier. The emulsifier acts as a medium between the immiscible oils and waters in the mixture, allowing them to coexist in a stable state. It is important to choose the right type of emulsifier for your asphalt emulsion because it will determine how quickly and thoroughly the emulsion breaks, how well it holds up during application and storage, and how effective it will be in the field.
There are several types of asphalt emulsions. Each has its own unique properties that make it suitable for a particular application. The most common are anionic, cationic, and nonionic. Each type has a different electrical charge around its aggregate particles and is designed to interact with specific types of aggregates. They also break at different rates and are further classified by their viscosity and whether they use a hard or soft base asphalt. Trailing numbers and letters denote the chemistry of the emulsion; for example, RS means rapid set, MS is middle of the road, and SS is slow to set.
The emulsion can be improved with a variety of additives. These can be added to improve the elasticity, adhesion, and other performance characteristics of the emulsion. These additives can also help reduce the amount of energy required to produce the emulsion, decrease the need for high-energy heating processes, and lower greenhouse gas emissions. It is important to select the right additives for your emulsion because mixing the wrong chemicals will destabilize the emulsion and cause it to break down. In addition, the type of water used can influence the stability of the emulsion. For this reason, distilled or deionized water is often preferred.
Coal tar
Many parking lots and driveways across North America are coated with a dark, viscous liquid called sealcoat to maintain and improve the appearance of asphalt pavement. However, this coating contains coal tar, which is highly toxic to both humans and aquatic life. Coal tar is a residue byproduct of the coking, liquefaction or gasification of coal, and it is composed of various polycyclic aromatic hydrocarbon compounds (PAHs) and their methyl and polymethyl derivatives. PAHs are known and probable carcinogens that may also cause other diseases in both humans and aquatic life.
Runoff from pavement treated with coal tar sealant is a significant source of PAH contamination in urban and suburban waterways, posing a threat to human and animal health. Coal tar sealant releases a high percentage of its PAHs to the atmosphere upon application and continues to release them at much higher levels long after it has been applied.
These volatile chemicals can be carried in the air and released into aquifers where they can contaminate groundwater. Runoff from sealed pavement can contain PAHs in concentrations ten to one hundred times greater than concentrations in adjacent untreated asphalt. In a study by the City of Austin Texas and U.S. Geological Survey, PAHs from the runoff of coal tar-sealed pavement killed minnows and water fleas within 42 days.
PAHs are also released to the atmosphere from coal tar sealcoat during the curing process. The release is triggered by a chemical reaction in the presence of ultraviolet light, with a wavelength of activation between 340 and 430 nanometers. When exposed to UV, coal tar pitch, creosote and similar products cause a painful burning stinging sensation in the skin that is often referred to as “tar smarts”.
Coal tar is listed on the EPA’s Hazardous Substance Data Base (HSDB) under Category VI (reactions that have been determined to be irreversibly hazardous) and is subject to DOT’s regulations for transporting hazardous materials. Those regulations include the preparation of a Material Safety Data Sheet (MSDS) and a Transport Accident Report Form. It is also subject to the requirements of hazard communication and a public education program.
Other materials
Choosing the right sealcoat material is important. It determines the longevity of your driveway, traction in rain and snow, resistance to chemicals and other destructive elements. It also determines the appearance of your asphalt pavement. However, not all sealcoat materials are created equal. Some companies use low quality sealers to cut costs, while others adhere to rigorous standards and offer only the best products. If you want to find a reputable sealcoating contractor, it is essential to understand the different ingredients and what to look for in a quality product.
A good sealcoating contains four major ingredients that work together to create a long lasting, smooth surface. A sand aggregate mix provides skid resistance, while the asphalt binder serves as the glue that holds everything together. Polymer additives provide toughness, tensile strength and color stability. Finally, the admixture provides a waterproof seal to keep water out of your driveway and limit damage from traffic and UV rays.
The most common sand/asphalt emulsion sealcoats have an ingredient called a polyvinyl acetate or acrylic copolymer which is used to thicken the mixture, produce uniform texture and fill minor surface defects. This type of polymer has excellent resistance to oils, mild acids, kerosene and other petroleum products, but it has poor resistance to ozone, esters and ketones.
Chloroprene rubber (Neoprene) polymers are commonly used in industrial compositions to make gaskets and adhesives, but they also contribute significantly to the performance of commercial sealcoatings. They have excellent resistance to chemicals, oils, lubricants and solvents, but they have poor resistance to ozone, ketones and chlorinated compounds.
Other additives are also used in sealcoatings to improve specific properties such as resistance to salt, deicing chemicals and jet fuel. These polymers are often referred to as “rubberizing” additives.
Adding these additives does not overcome or compensate for the deficiencies introduced through improper mix design, such as excessive amounts of water and sand/aggregates. Excessive amounts of water lower the total solids in a sealcoat and reduce the film’s flexibility, adhesion, chemical and fuel resistance. Excessive sand/aggregate additions reduce the ability of the sealcoat to fill cracks and crevices and cause premature failure.