IRC 120:2015 outlines detailed guidelines for recycling bituminous pavements, addressing both cold and hot recycling techniques such as cold in-place, cold in-plant, hot in-place, and hot in-plant methods. This standard assists engineers and pavement specialists in evaluation, material preparation, processing, mix design, and quality control to maximize the sustainable reuse of reclaimed bituminous materials for effective pavement rehabilitation and rebuilding.
Overview
IRC 120:2015 outlines detailed guidelines for recycling bituminous pavements, addressing both cold and hot recycling techniques such as cold in-place, cold in-plant, hot in-place, and hot in-plant methods. This standard assists engineers and pavement specialists in evaluation, material preparation, processing, mix design, and quality control to maximize the sustainable reuse of reclaimed bituminous materials for effective pavement rehabilitation and rebuilding.
Audience
Contents
Structure
Frequently Asked
As per IRC 120, sampling reclaimed bituminous materials (RBM) involves collecting bulk samples of approximately 150 kg during field investigations or excavation of test pits. Upper pavement layers around 300 mm thickness should be sampled separately using milling machines or recyclers. For mix design purposes, key tests include determining bituminous binder content, aggregate gradation, bulk specific gravity, and properties of recovered aggregates. When reclaimed bituminous content exceeds 35%, binder properties of RBM must also be evaluated. Testing methods for bitumen content and aggregate recovery include ignition, centrifuge extraction, and reflux extraction techniques, each with their own benefits and limitations. This approach ensures accurate and reliable data to guide mix design and recycling processes.
To maintain the quality of reclaimed bituminous material (RBM) stockpiles and avoid contamination, IRC 120 recommends strict control measures such as ensuring stockpiles remain free from dirt, debris, vegetation, or foreign materials from the outset. Dumping must be confined to designated zones, with truck beds cleaned before loading RBM. Continuous monitoring by quality control staff and loader operators is essential to detect any contaminants early, which should be removed immediately to prevent mixing. To minimize segregation of materials, indexing conveyors that move as the pile grows are advisable, alongside remixing with loaders if segregation occurs. Treating RBM stockpiles as valuable assets helps preserve material quality and ensures efficient recycling.
The equipment required for cold in-place recycling (CIR) includes cold milling machinery to remove existing pavement layers, conveying systems to transport milled materials to vibrating screens, and separate lines for fresh aggregate input. A proportioning and weigh batching system is used for accurate blending of different size fractions. The pug mill mixes milled materials with binders, aggregates, and rejuvenators, with separate feed lines for each component. Vibrating screeds are employed to tamp and profile the mixed materials, followed by compaction equipment to consolidate the recycled layer. Additional equipment includes dust and noise control systems and electronic control units for automated process management. This setup supports efficient simultaneous milling, mixing, paving, and compaction of recycled pavement layers.
IRC 120 outlines several RBM processing options, each with distinct benefits and drawbacks. Using millings without further processing avoids additional crushing, allowing higher reclaimed asphalt pavement (RAP) content and lowering costs; however, it requires multiple stockpiles and may introduce variability that necessitates new mix designs. Screening RAP before crushing reduces dust generation and preserves aggregate quality but is limited by the availability of screening facilities. Crushing all RAP to a uniform size offers versatility for multiple mix types and uniformity but increases dust, limiting RAP usage. Fractionating RAP provides greater mix design flexibility by separating sizes but requires extensive stockpile space, is costlier, and risks producing excess oversized RAP. Balancing these factors is crucial for optimizing RAP processing.
Determining recycling depth according to IRC 120 involves assessing the pavement's residual structural life and extent of distress. If the residual life exceeds five years, only surface layer recycling is recommended when distress is confined to the surface. If residual life is below five years and distress extends into the bituminous base, recycling combined with overlay is advised. For distress that reaches the granular or bound base layers, full depth reclamation involving pulverization of the base and recycling of bituminous layers is necessary. Serviceability indicators such as high severity distress, roughness exceeding 3000 mm/km, and rut depths over 20 mm guide these decisions. This ensures recycling depth aligns with the actual structural condition and distress severity.
Ask AI about any clause, requirement, or provision in IRC 120. Get instant, clause-cited responses powered by our indexed library.
Free tier includes 150 queries (50 AI + 100 Reference) · No credit card required