|The ConAsphalt™ Plant|
The ConAsphalt™ Plant
Introducing the Multi-Mix Production Facility
Astec, Inc. is focused on helping the contractor produce appropriate materials, concrete or asphalt, which fit the scope of the project application.
hether the project involves work on an airport where the base for the runway is asphalt and the top paving surface is concrete, or working on a project where the base is roller-compacted concrete and the driving surface is asphalt, these projects call for the ability of the contractor to produce more than one material in order to meet the project specifications.
Under conventional means, a contractor would need two different kinds of production plants to produce the two different needed materials on a project. And in cases where the jobsite is not in a delivery range of a stationary facility such as an asphalt or concrete plant, being able to produce all the materials for a project would be advantageous for the contractor. The contractor would then be able to bid both parts of the contract and self-perform, realizing a stronger financial outcome of the job. The contractor would also be able to directly control the specifications of the mixed materials with his own company versus using a subcontractor.
In order to provide production of mixed materials, Astec, Inc. took a closer look at the structural components of aggregate with a binder, such as asphalt cement for making hot-mix asphalt or Portland cement for making concrete, and found that both materials have a similar constituent makeup and the variable is the addition of either asphalt cement or Portland cement (with water or other additives) to create the desired mix.
Most concrete for road building is produced in a plant with a mixer, either a tilt-drum mixer or a twin-shaft mixer. Every asphalt and concrete plant has components that help proportion the materials, including the sand. The bin system in the ConAsphalt™ plant concept would be referred to as the Aggregate Management System, whereas on the asphalt plant, the units are called the cold feed bins, or referred to as aggregate bins on the concrete plant. The ConAsphalt™ plant would manage the production of both asphalt and concrete with the same group of aggregate bins. The contractor would then improve the profitability and consistency of the materials by using Fractioned Aggregates for either material, concrete or asphalt, in the multi-bin Aggregate Management System.
How This Would Work
When the aggregates are moving up the incline conveyor to go into the Double Barrel® dryer/drum, there would be a calibration chute that would be modified to be a diverter chute. That chute would take the aggregates over to the twin-shaft mixer to make concrete or on to the dryer/drum for hot-mix asphalt. In other words, the ConAsphalt™ single plant footprint would have the mechanical devices to make either product simply by engaging the right controls to move the aggregates to the appropriate mixer. The concept, ConAsphalt™, becomes a multi-mix production facility.
The desirability of the multi-mix production facility centers on the fact that there is an entire range of products within the asphalt and concrete world that are different from one another, such as SMA and warm mix asphalt, and cold mix used for patching. On the concrete side, there is a cement-treated base which provides the material between the grade and the pavement—an important element of good road or runway construction. Another process is soil amendment for large structures requiring a strong foundation. Cement-stabilized soil ensures flat, level floors for warehouses or other industrial facilities. Any of these products, including conventional concrete and roller-compacted concrete, could be produced in the ConAsphalt™ plant.
This concept can also be a retrofit with installation taking a few days or no more time than the typical plant install. Astec can convert the asphalt plant into a ConAsphalt™ operation and truly be the solution to the contractor needing to expand into other revenue streams. With Astec technology and the ConAsphalt™ plant concept, asphalt or concrete producers could become multi-material providers, increasing the financial strength of their companies.
This article originally appeared in Hot-Mix Magazine Vol. 16 num. 1