Where is asphalt produced

Since asphalt cement is a major constituent used in road paving, the following is a brief There are two types of asphalt mixes: hot-mix and cold-mix. Hot-mix asphalt HMA is commonly used for heavier traffic areas while cold-mix asphalt is used for secondary roads.

Asphalt paving mixes made with asphalt cement are usually prepared at an asphalt mixing facility. There are two types of asphalt mixes: hot-mix and cold-mix.

Hot-mix asphalt HMA is more commonly used while cold-mix asphalt generally mixes made with emulsified or cut-back asphalts is usually used for light to medium traffic secondary roads, or for remote locations or maintenance use.

Hot-mix asphalts are a mixture of suitable aggregate coated with asphalt cement. The term "hot-mix" comes from the process of heating the aggregate and asphalt before mixing to remove moisture from the aggregate and to obtain sufficient fluidity of the asphalt cement for proper mixing and work-ability.

The quality of asphalt cement is affected by the inherent properties of the petroleum crude oil from which it was produced. Different oil fields and areas produce crude oils with very different characteristics. The refining method also affects the quality of the asphalt cement.

For engineering and construction purposes, there are three important factors to consider: consistency, also called the viscosity or the degree of fluidity of asphalt at a particular temperature, purity, and safety. The consistency or viscosity of asphalt cement varies with temperature, and asphalt is graded based on ranges of consistency at a standard temperature.

Careless temperature and mixing control can cause more hardening damage to asphalt cement than many years of service on a roadway. A standardized viscosity or penetration test is commonly specified to measure paving asphalt consistency. Air-blown asphalts typically use a softening point test. Purity of asphalt cement can be easily tested since it is composed almost entirely of bitumen, which is soluble in carbon disulfide.

Refined asphalts are usually more than Because of the hazardous flammable nature of carbon disulfide, trichloroethylene TCE , which is also an excellent solvent for asphalt cement, is used in the solubility purity tests. Asphalt cement must be free of water or moisture as it leaves the refinery. However, transports loading the asphalt may have moisture present in their tanks. Asphalt cement, if heated to a high enough temperature, will release fumes which will flash in the presence of a spark or open flame.

The temperature at which this occurs is called the flashpoint, and is well above temperatures normally used in paving operations. Because of the possibility of asphalt foaming and to ensure an adequate margin of safety, the flashpoint of the asphalt is measured and controlled. Another important engineering property of asphalt cement is its ductility, which is a measure of a material's ability to be pulled, drawn, or deformed.

In asphalt cements, the presence or absence of ductility is usually more important than the actual degree of ductility because some asphalt cements with a high degree of ductility are also more temperature sensitive. Asphalt can also reduce splashing and spraying from tires during precipitation, reducing collisions on the highway. When compared to other types of hard surfaces, asphalt is far more cost effective. It lasts longer and requires less maintenance.

Smoother roads also reduce the wear and tear on vehicles. Therefore, they save vehicle owners money on maintenance. Asphalt is a recyclable product. In the United States, the asphalt industry recycles almost million tons of asphalt pavement annually for reuse in other areas. Asphalt pavements can be designed for low, medium or high-volume traffic. With routine maintenance, asphalt can last years. Oil wells supply petroleum to oil refineries, where it is separated into various factions, one of which — from the heaviest part of petroleum— is asphalt.

Asphalt for paving goes through a mixing process in either a drum mix plant, which is a large-output and continuously operating facility, or a batch plant, which is a smaller-output plant that mixes in batches.

There are a few different ways to mix asphalt, the most popular of which are hot and cold. Hot-mix asphalt is made by heating aggregates to decrease the viscosity of the binding agents and make the whole more fluid, then drying it to remove any remaining moisture. It is mixed hot at degrees Fahrenheit. It is called hot-mix because not only because it is mixed hot, it must also remain hot for the paving and compaction for repair or installation.

This need for the asphalt to remain warm while paving and compaction is performed is one of the reasons so much paving is done in the summer. Completed asphalt is evaluated for its quality in terms of consistency or viscosity, and purity.

These are important for the asphalt to be properly controlled, transported and used in paving projects. Hot-mix asphalt, abbreviated HMA, is normally used for high-traffic areas, such as main roads and highways, whereas cold-mix asphalt, or CMA, is typically used for paving secondary roads.

For HMA, asphalt and aggregate are mixed at a facility where it is first heated and then mixed to the desired consistency. Hot-mix plants may be set up at a permanent location or may be mobile, moving from job site to job site.

Another process called drum mixing heats and blends the asphalt and aggregate at the same time. The properly measured amounts of aggregate and asphalt are put into a chamber called a pugmill, mixed and then placed into trucks, or storage containers.

The hot-mix asphalt is then trucked to the jobsite and poured out and spread to a uniform thickness by a paving machine. The mixture is then compacted by heavy rolling machine while still hot to produce a even surface. The properties of asphalt are affected by the innate properties of the petroleum that it is made from. This is due to the fact that different oil fields and refining methods can result in crude oils with very diverse characteristics.

There are three essential factors that must be considered when asphalt is being used for construction purposes. Asphalt is graded based on the ranges of viscosity, or consistency, at a given temperature. Careless mixing- and temperature-control procedures can cause more damage to paving asphalt during the hardening phase than many years of vehicle traffic. A standardized penetration test is generally specified when determining paving asphalt consistency.

The purity of asphalt is easily tested, as it is made up almost completely of carbon-disulfide soluble bitumen. Refined asphalts are typically more than