Pavement Recycling Technology

Cold-in-place recycling (CIPR) restores damaged road pavements by reusing existing layers, mixing them with cement and additives, and relaying in one efficient process.

Sustainable Road Solutions

Our Pavement Recycling Technology, known as Cold-in-Place Recycling (CIPR), restores distressed road pavements efficiently. The process reuses existing pavement layers, mixes them with cement and stabilizing additives, and relays them on the same area in one seamless operation. This approach reduces material waste, lowers costs, and ensures durable, long-lasting road performance while supporting environmental sustainability.

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.

circumstances to consider cold-in-place recycling treatment

Cold-in-place recycling (CIPR) is best applied when pavements show moderate distress, such as surface cracking, rutting, or oxidation, but the underlying base remains structurally sound. This method is ideal for extending pavement life, reducing costs, and promoting sustainability without requiring full reconstruction.

advantages of CIRR treatment

Although beneficial, CIPR isn’t always the best option. It demands meticulous planning and a solid road base to work effectively. Before choosing CIPR, it’s crucial to assess the current pavement thoroughly and select appropriate materials and methods for the project’s requirements.

Environmentally Friendly

On-site pavement recycling greatly cuts carbon emissions by eliminating the need to transport new materials and dispose of old ones.

Cost-Effective

It reduces the need for new materials, lowering the cost of pavement rehabilitation.

Time-Efficient

The process can be faster than traditional pavement replacement methods, minimizing disruption to traffic.

Versatile

CIPR can be used on a variety of road types and conditions, making it a flexible solution for many projects.

Curing

The recycled layer must cure before opening to traffic or adding a new surface layer, with duration depending on the recycling agent and weather conditions.

Improved Pavement Performance

When properly executed, CIPR can enhance the structural capacity and longevity of the pavement.