Cold In Place Recycling Quality Assurance

Inspection Guidelines

With CIR, like most paving projects, the primary goal is to produce a strong, durable base course from existing pavement materials that is ready to receive a wearing surface. Inspectors can help achieve this goal by ensuring that the process is in accordance with the contract documents as follows:

Mix Design: Verify representative samples were obtained throughout the project and that a mix design(s) was performed by a qualified lab resulting in a mixture that meets or exceeds the contact documents.

 Surface Preparation: Walk or drive the entire pavement to be paved for the day to ensure the surface has been properly prepared and that all pre-construction repairs have been performed. 

Acceptable Weather: Measure the air and pavement temperature and check conditions for anticipated heavy rainfall to determine if construction can start/continue.

Traffic Control: Verify that the proper traffic control is in place to keep the traveling public safe and out of freshly placed CIR.

 Quality Equipment:

• Verify that the on-board recycling agent/additive system of the recycling train is equipped with a meter capable of recording the rate of flow and total amount of each liquid being added to the recycled material.
• Verify that nozzles and spray bars are working properly and are not plugged.
• Verify that the recycling train is removing the material to the required width and depth.
• For multi-unit trains, verify that the crushing and screening unit is functioning properly by checking the maximum size of RAP.
• For foamed asphalt, verify that the proper half-life and expansion ratio is being maintained.
• Check the recycled mixture for uniformity and homogeneity as it is discharged onto the pavement and windrowed or deposited directly into the paver hopper or screed.
• Verify that the compaction equipment is of the required type, number and size and that scrapers and spray bars are properly working.

 Quality Workmanship:

• Verify that the recycled mixture is being placed to the proper depth, grade and cross-slope.
• Verify that the width of milling overlaps the previous pass by the required minimum amount.
• Ensure that the transverse and longitudinal joints are properly constructed.
• Verify that paving fabric or crack sealer that exceeds the maximum size is removed from the recycled mixture.
• Verify that a control strip was established to determine proper compaction procedures.
• Verify that the rolling procedure established in the control strip is followed and that the compacted density is within the specified range. Reestablish the rolling pattern if the density of the recycled mixture is not in compliance.

Application Rates: Periodic checks should be made to verify that the amount of material being added to the recycled mixture is within the allowable tolerances.