Cold In Place Recycling Methods

As a general rule, to achieve the same structure, a hot mix lift can be replaced by a CIR layer that is 15% to 25% thicker (eg. 1” hot mix ~1.25” CIR).

A pavement design with appropriate traffic levels will tell you how thick the CIR layer needs to be.

To get the best bond, let the CIR cure for 3-10 days after construction (and 24 hours after any rainstorm) before applying the tack coat and final pavement surface.

Note: CIR works best when there is 1” - 2” of existing asphalt pavement below the CIR layer. With thicker underlying asphalt , reflective cracks may come thru sooner. So check your boreholes to see if CIR+CCPR is right for you.

Here is an example of the limits of crossfall correction: 

• Existing road at 0%, recycle 75mm deep, place at 0%, CIR layer will be 89 mm deep
• Existing road at 0%, recycle 75mm deep, place at 1%, CIR layer will be 70 mm deep
• Existing road at 0%, recycle 75mm deep, place at 2%, CIR layer will be 51 mm deep

If a CIR mix ravels excessively due to rain, the mat can be re-processed with or without adding cement to facilitate drying.

In urban areas, notify the public about upcoming work. Inform residents that the project allows quick return to traffic, with minimal impact to businesses.