What Is Cold In-Place Recycling?
What Is Cold In-Place Recycling?
Cold In-place Recycling (CIR) is a process that rehabilitates a road using existing pavement materials on-site.
These materials are mixed together without heat using milling, crushing, or planing techniques.
Virgin aggregate or recycling agents may be added to the reclaimed asphalt pavement (RAP) material before it is compacted into place.
This method can repair a road by addressing issues such as potholes, roughness, and cracks, and can also restore the road’s original profile and slope.
CIR is becoming more popular due to its potential for cost savings, high production rate, minimal disruption to traffic, and environmental benefits.
It is particularly useful for secondary roads that are located far from a central plant, as it does not require the RAP to be transported to and from a central location.
What Is Added As A Recycling Agent In Cold In Place Recycling Method?
A binding agent, such as emulsified asphalt, lime, portland cement, or fly ash, is added to the ground up material.
Sometimes this is done by the milling machine, while on other occasions a trailer-mounted pugmill mixer is used.
What Are Two 2 Distinct Types Of Cold In Place Mix Recycling (CIPR)?
There are two different types of cold in-place recycling: foamed asphalt stabilized and asphalt emulsion stabilized.
Foamed asphalt stabilized base (FASB) is made by combining reclaimed asphalt pavement (RAP) and/or recycled concrete (RC) with a foamed asphalt binder.
It has structural properties that are intermediate between those of conventional graded aggregate base (GAB) and hot mix asphalt (HMA).
This means that the thickness of the pavement layer can be reduced, leading to cost savings as well as environmental benefits through the recycling of materials.
Asphalt emulsion, which is often used to stabilize pavement base courses, can be enhanced in terms of stability by adding cement as a filler.
However, this comes at the cost of higher material expenses and potential environmental concerns.
What Materials Can Be Used For Stabilizer For Cold In Place And Full Depth Reclamation FDR Recycling?
Materials commonly used for stabilizers during cold in place and full depth reclamation (FDR) recycling include cement, lime, fly ash, and bituminous agents.
Cement is a pozzolanic material that increases stiffness when mixed with the recycled pavement material, thus producing a stronger stabilized base. Lime adds a subtle acidity to the soil, helping to reduce its plasticity.
Fly ash is an additional pozzolanic material that helps improve strength as well as reducing shrink-swell properties of the recycled pavement material.
Finally, bituminous agents serve to coat recycled aggregates which helps protect them against weathering while adding flexibility and workability.
All of these materials are essential to creating quality stabilization layers while preventing future cracking or rutting of distressed pavements.
How Is Cold In-Place Most Effective?
Cold In-Place Recycling (CIR) has numerous benefits and is most effective for low- to moderate-volume roads without structural issues.
CIR can fix deep asphalt defects such as rutting and alligator cracking, as well as utility cuts that cannot be fixed with a surface treatment or overlay. It can also slightly adjust the road profile if material is added or removed by pre-milling.
Additionally, CIR can reduce reflective cracking, which is caused by concentrated stress and can lead to water infiltration and faster pavement deterioration. However, it may not be suitable for all roadway paving projects.
