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Subcontractor
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  • 03 9285 2257
  • info@roadcare.com.my

Cold in Place Recycling (CIPR)

Cold-in-place recycling (CIPR) is a technique for treating distressed road pavements. The recycling machines scarifies the existing pavement layers then add cement as stabilizing additives before laying it on the same pavement area in a single process.

Methodology and process involved in cold-in-place recycling procedure

Assess the existing pavement structures, noting the types, conditions, thickness, material types, and any visible distress or degradation of each layer.
  • Perform a plasticity index test on soil or aggregate samples to evaluate their plasticity characteristics, which influence workability and stability.
  • Test the aggregate crushing value (ACV) to assess the strength and durability of the aggregates used in the pavement mix.
  • Measure the flakiness index to determine the shape and texture of the aggregates, which affect the performance of the pavement.
  • Conduct the California Bearing Ratio (CBR) test to evaluate the load-bearing capacity of the subgrade or sub-base materials, informing the design of the new pavement structure.
  • Analyse the gradation of aggregates to ensure that their particle size distribution complies with the specifications required for the pavement mix.
Develop a mix design for the asphalt or concrete to be used in the reconstruction, ensuring that the proportions of materials achieve the required performance standards for durability and load-bearing capacity.
Complete a structural design of the pavement to determine the necessary layer thicknesses and material specifications, ensuring the pavement will support the anticipated traffic loads and environmental conditions.
  1. Clearly mark and delineate the construction area to define work boundaries and ensure safety and efficiency throughout the process. Reshaping existing pavement if only it is required (example: Topping up crusher run).
  2. Setting up the recycle train.
  3. The determined recycle stabilization areas shall be marked and the required quantity of cement shall be spread over the areas.
  4. The cement used in the cold in-place recycling process shall be ordinary Portland cement complying with MS 522.
  5. Recycling Work: The mixed material or known as reclaimed asphalt pavement (RAP) shall be continuously placed back in the excavation created by milling as the recycler advances.
  1. After at about 3m of CIPR operation, moisture content should be obtained to determine application rate of water can achieve optimum moisture content (OMC). OMC ± 20%.
  2. Loose CIPR samples behind the recycler shall be tested for grading, proctor, UCS, ITS.
Initial compaction shall be undertaken by a smooth-drum or pad foot vibrating roller, operating on high-amplitude vibration. The operating speed of the primary roller shall never exceed 3km/hr and rolling shall be applied over the full width of each cut.
  1. After primary rolling has been completed a grader shall be used if required to cut the final surface levels.
  2. Grader works shall be limited to the minimum necessary to achieve the required final surface shape, evenness and texture.
  3. Skimmed material shall be removed and under no account compacted into the trimmed layer.
  1. Final compaction comprises secondary rolling, to achieve the specified density, and finishing. Secondary rolling shall be undertaken using a smooth-drum vibrating roller (nominal 12 tonne static mass) operating on low-amplitude vibration.
  2. Finishing shall be undertaken with a pneumatic-tyred roller to achieve a close-knit surface appearance.

Field Density Test (FDT): Upon completion of rolling, FDT is carried out at 250m or 500m². FDT requirements:  >95% (crusher run)  ;  >97% (RAP + crusher run) ;   >98% (RAP)

UCS, ITS, Grading and FDT tests to be carried out ≤ 72 hours CIPR samples shall be tested to achieve; UCS > 2.0 MPa; ITS > 0.2 MPa, grading with sieve envelope; FDT: >95% (crusher run)  ;  >97% (RAP + crusher run)  ;  >98% (RAP)

  • The Asphaltic Concrete Binder Course (ACBC) 28 must comply with the standard specifications established through plant trial.
  • This compliance includes successful completion of testing for sieve analysis, bitumen content, and Marshall properties.
  • The rolling compaction pattern must be established and applied effectively thus, achieve a Marshall density of 95%.
  • The average thickness over any 100-meter length ≥ the required thickness. The minimum thickness at any point should be at least the required thickness ± 5 mm, as verified by coring.
  • The Asphaltic Concrete Wearing Course (ACWC) 14 must comply with the standard specifications established through plant trial.
  • This compliance includes successful completion of testing for sieve analysis, bitumen content, and Marshall properties.
  • The rolling compaction pattern must be established and applied effectively thus, achieve a Marshall density of 98%.
  • The average thickness over any 100-meter length ≥ the required thickness. The minimum thickness at any point should be at least the required thickness ± 5 mm, as verified by coring.
Apply temporary road marking for safety of road users. Then, apply Permanent road marking work shall be carried out after 72 hours.
The defect liability period for the project is either 6 or 12 months, depending on the project cost.