Cold in Place Recycling
The asphalt pavement and a minimal amount of the underlying base are pulverized and blended.
What It Is
Cold in Place Recycling (CIR) is a process in which existing asphalt pavement is rejuvenated into a new pavement structure in–situ without the use of heat. During the process, the pavement is first cold milled to a depth sufficient to ensure the inclusion of the entire thickness of asphalt concrete pavement into the new blend. The material is then sized to a predetermined gradation and blended with an asphalt emulsion that acts as the binder for the new material. Preliminary testing determines the application rate of the emulsion utilized. The blended material is then replaced and compacted on the roadway to act as base asphalt for a final finished surface.
Cold in Place Recycling (CIR) is a process in which existing asphalt pavement is rejuvenated into a new pavement structure in–situ without the use of heat. During the process, the pavement is first cold milled to a depth sufficient to ensure the inclusion of the entire thickness of asphalt concrete pavement into the new blend. The material is then sized to a predetermined gradation and blended with an asphalt emulsion that acts as the binder for the new material. Preliminary testing determines the application rate of the emulsion utilized. The blended material is then replaced and compacted on the roadway to act as base asphalt for a final finished surface.
Reasons For Use
Cold in Place is recommended for use when the existing asphalt surface has deteriorated to the point where it is not practical or economical to rehabilitate the road using more commonly utilized methods. Some alternative methods do not repair the entire thickness of the pavement layer while others rely on the removal and replacement methodology. CIR increases the strength and endurance of the road by providing an increase in the granular thickness of the existing structure. With the combination of the final wearing course a thicker course of flexible pavement is achieved.
Cold in Place is recommended for use when the existing asphalt surface has deteriorated to the point where it is not practical or economical to rehabilitate the road using more commonly utilized methods. Some alternative methods do not repair the entire thickness of the pavement layer while others rely on the removal and replacement methodology. CIR increases the strength and endurance of the road by providing an increase in the granular thickness of the existing structure. With the combination of the final wearing course a thicker course of flexible pavement is achieved.
Emulsified asphalt is then added to the pulverized material using computer–integrated controls at rates determined through preliminary testing.
The compacted emulsified base is then left to cure for a predetermined duration prior to placement of a final wearing surface.
The emulsified material is then graded and compacted to specified densitites and desired crossfalls.
Due to the increase in strength from the CIR method of rehabilitation, a modification from the type or thickness of finished wearing surface is normally realized.
Other benefits of cold in place recycling include the reduction in demand for our natural resources, reduced haul costs and traffic, and the elimination of the re–occurance of reflective cracking.