What is the difference between asphalt and concrete?
Asphalt is a pavement structure consisting of aggregates, fines and a binder of liquid asphalt. The material is applied hot and is cured once it cools. Concrete is a pavement structure consisting of cement, aggregates, water and chemical admixtures. The material is applied cold and is cured once the water evaporates out. Generally, concrete is more expensive to install, but it also will have a longer lifespan.
How thick should asphalt be?
Asphalt should be poured at a minimum thickness of 2″. This is an appropriate depth for most commercial applications. The greater the weight-load capacity required, the thicker the asphalt should be. Areas with a high volume of traffic or heavy trucks (garbage trucks, semis, etc.) should have thicker depths.
What makes for an appropriate sub-base?
An appropriate sub-base layer will be designed and engineered for the appropriate weight load-bearing capacity needed. The more weight that the surface asphalt layer will be bearing, the more sophisticated the sub-base should be. The sub-base consists of aggregates (or crushed rock) and fines. A mixture of 5/8 minus crushed rock is appropriate for most of our applications.
What temperature is asphalt when it’s laid?
Asphalt is approximately 300 degrees when it is picked up from the asphalt plant. It should be spread and appropriately compacted before it cools to less than approximately 200 degrees.
What time of year can asphalt patching be performed in Puget Sound?
We operate patching crews 12 months of the year and have equipment where we can keep our mix warm at the job site. Mixture should be laid and compacted before it cools to less than 200 degrees.
How much does it cost?
The factors that affect the cost of an asphalt patching job are (1) total square footage of the job (2) size of the individual patches (3) access to work site (4) amount of sawcutting, excavation and preparation necessary (5) thickness of the asphalt/materials necessary.
How is patching different than paving or an “overlay?”
Asphalt “patching” involves removing the old, damaged layer of asphalt and installing new asphalt onto the existing sub-base or sub-grade. An “overlay” involves placement of new asphalt on top of the old, damaged asphalt.
What happens if I don’t patch?
Most asphalt decay starts as a single crack and will ultimately develop into more widespread cracking. Any exposed cracking or decay at the surface allows moisture to penetrate underneath and impact the integrity of the sub-base. The more moisture that reaches the sub-base, the more likely there is to be widespread damage at the surface.
What factors contribute to asphalt decay?
Asphalt will decay because of factors above the surface and factors below the surface. A well-designed and well-constructed asphalt pavement structure will be better able to resist above-surface decay contributors. During construction, the asphalt should have an appropriate type of sub-base rock, which should be compacted properly. During installation of the asphalt surface, the mix should retain an appropriate amount of heat (above 200 degrees) before it is compacted, and the material should be compacted with proper equipment. Above-surface factors that contribute to asphalt decay are: rainfall, freeze-thaw cycles, snow and ice, foreign substances such as sand, salt and oil or gas leaks, sun oxidation, heavy equipment or vehicles.
How long before I can drive on it?
Typically, newly laid asphalt can be driven on within several hours. The colder the weather, the sooner it is traffic ready. We usually employ a “touch test.” If the surface is cool to the touch, it is ready to be driven on. However, asphalt will take several weeks to cure to its ultimate hardness and exposure to heavy trucks or equipment should be avoided if possible shortly after completion.
What are the different types of asphalt (grades)?
The most common types of asphalt mixture are Class A, Class B, Class B Modified and Class G. Class A has the largest aggregate and the least amount of fines. It is intended for heavy road construction and is more porous after completion. Class G (or playground mix) is a mix that uses all fines. It has a very smooth finish, but lacks structural integrity for much weight-bearing capacity. It is appropriate for asphalt walkways or paths. Class B modified is the most common mix and is appropriate for most light-use and commercial applications. It has a medium-sized aggregate and an abundance of fines which provides both structural integrity and a smooth finished product.
Who makes your asphalt?
We purchase asphalt from various asphalt manufacturing plants around Puget Sound including Cemex (formerly Rinker), Lakeside Industries, Tucci and Sons, Woodworth and Western Asphalt.