Recycled materials like recycled concrete aggregates can perform similarly to natural aggregates in pavement layers, though they may have slightly lower strength and density. With proper processing, they offer an environmentally friendly and cost-effective alternative while maintaining adequate pavement performance.

Ali. Jaafar Dakhil

Recycled materials, when properly processed and quality-controlled, can achieve comparable or even superior performance to natural aggregates when used as a full replacement in pavement layers, particularly in lower (non-structural) layers. Their use supports sustainable development by conserving natural resources and reducing construction and demolition waste. However, the performance of recycled materials largely depends on their type, origin, processing, and physical-mechanical properties. Materials such as recycled concrete or asphalt can exhibit adequate load-bearing capacity and stability but may present increased porosity and variability, which can affect long-term pavement performance. For upper, load-bearing, and surface layers, where requirements for durability, freeze-thaw resistance, wear, and moisture sensitivity are more stringent, comprehensive laboratory and field testing is essential. Additionally, the application of recycled materials must comply with relevant technical regulations and standards. Considering all of the above, recycled materials can represent a valid alternative to natural aggregates, but their use requires careful planning, validation through testing, and expert monitoring of in-service performance.

Recycled materials, such as recycled concrete aggregate (RCA) or reclaimed asphalt pavement (RAP), can achieve comparable performance to natural aggregates in certain pavement layers, but full replacement depends on the application and quality control. In unbound base or sub-base layers, well-processed recycled aggregates often meet strength, stiffness, and durability requirements, sometimes offering better compaction and drainage due to their angular shape. However, challenges include higher water absorption, potential contamination, and variability in properties, which require strict processing and testing. In bound layers (e.g., asphalt or concrete), performance parity is harder to achieve without mix design adjustments or additives. With proper grading, moisture control, and binder optimization, recycled materials can match or even surpass natural aggregates in sustainability and lifecycle cost, while reducing environmental impact. Nonetheless, their suitability should be validated through performance testing for the specific project conditions and traffic loads.