The components of hot mix asphalt can be simplified into two major components; liquid asphalt cement and aggregates. The liquid asphalt cement (often called asphalt "binder") is material that coats the aggregate particles and acts as the glue that holds the mix together. The aggregates may consists of natural aggregates (river gravel and sands) or processed aggregates (from quarry and blasting operations). The aggregates provide the structure and framework that gives an asphalt mixture its stability and strength. Another vital component to a well-constructed asphalt pavement is the presence of air voids in the mixture. The amount of air voids in the asphalt is controlled through the aggregate gradation and the quantity of liquid asphalt. The proper blend of asphalt and aggregates is determined prior to construction (during the mix design phase) in order for the mixture to have the desired properties.

No, it is a common misconception that asphalt is asphalt and that the asphalt used on the interstate roadways is the same asphalt used in residential driveways. An asphalt mixture that is designed for use on a heavily traveled highway has very different characteristics than those used in low volume residential applications. Those differences may include different aggregate types, sizes and proportions as well as different grades of liquid asphalt. Feel free to contact the PAIKY office or your local PAIKY producer member to assist you in determining which mix is appropriate for your application.

Superpave is a system of material specifications and laboratory mix design methods based on performance criteria developed under the Strategic Highway Research Program (SHRP). Using the Superpave system, materials and mixes can be designed to reliably perform under any loading or environmental conditions. The Superpave system is undergoing continuing development nationally. The Kentucky Transportation Cabinet has to fully implemented Superpave on January 1, 2000 for all state projects. In general, Superpave designed asphalt mixtures rely more on stone-to-stone contact , they are generally more durable and last longer.

Hot mix asphalt is the most economical paving material in the world. Pavements can be evaluated on both “initial cost” and “life cycle cost.” In the vast majority of circumstances, hot mix asphalt will provide the most economical solution in terms of initial cost and also when evaluated over a 30 to 40 year period. This is one of the reasons 94% of all paved roads in the U.S. are paved with asphalt

There really are many reasons to prefer an HMA pavement including: smoothness, quiet, stage construction, ease of maintenance, speed of construction, least user delay cost, ease of repair of utility cuts, no cure time, recyclability and now, that technology exists to design HMA mixtures to reliably perform under any conditions of load and environment, there is no reason to consider anything else.

In many respects Hot Mix Asphalt (HMA) is the environmentally friendly paving material. First, HMA materials are 100% recyclable. Virtually all of the reclaimed Asphalt Pavement (RAP) that is removed from existing streets and highways is recycled into new HMA. Because this recycling of HMA is economical, it occurs without the need for government mandates or subsidies.

Improvements in technology have been steadily reducing the airborne emissions from the production and placement of HMA. Dust from the drying of aggregates is the major emission and is now almost totally captured and recycled. Other emissions are primarily combustion products from the burning of fuel to heat the aggregates and fumes from hot asphalt itself. Fuel burners are now much more efficient, resulting in very complete combustion. Studies to date by the government and industry have shown emissions levels to be very low and have not identified any health hazard associated with exposure to asphalt fumes. The Environmental Protection Cabinet (EPA) has recently “delisted” asphalt plants because they pose no know risk to the public. Nevertheless, the industry continues to develop improved technology for reducing emissions and minimizing exposure.

Studies have shown that a smooth ride is the number one concern of road users. Furthermore, another study has shown that initial smoothness improves the performance and lowers the maintenance cost of a pavement over its life cycle. HMA pavements start out smoother and stay smoother throughout their lives, making them the best choice for new construction.

Gasoline taxes and other highway user fees are used to pay for road construction and maintenance in Kentucky. The people that use the roads, including the general public, businesses (trucks) and visitors to the state pay these taxes and fees. Currently, Kentucky has one of the lowest gasoline taxes in the United States but additional funds are needed to maintain our existing roadway system and to create new roadways throughout the Commonwealth. Additional funding would allow for structural and safety improvements to roadways throughout the state. Since Kentucky has a disproportionate number of deaths occurring from crashes on narrow, two-lane roadways, the welfare and safety of our citizens is at stake. Kentucky has a billion dollar investment in roads and bridges. This huge investment must be protected and properly maintained.